structs.go

package structs

import (
	"bytes"
	"container/heap"
	"crypto/md5"
	"crypto/sha1"
	"crypto/sha256"
	"crypto/sha512"
	"encoding/base32"
	"encoding/base64"
	"encoding/hex"
	"errors"
	"fmt"
	"io"
	"math"
	"net"
	"net/url"
	"os"
	"path/filepath"
	"reflect"
	"regexp"
	"sort"
	"strconv"
	"strings"
	"time"

	"github.com/gorhill/cronexpr"
	"github.com/hashicorp/consul/api"
	hcodec "github.com/hashicorp/go-msgpack/codec"
	multierror "github.com/hashicorp/go-multierror"
	version "github.com/hashicorp/go-version"
	"github.com/hashicorp/nomad/acl"
	"github.com/hashicorp/nomad/helper"
	"github.com/hashicorp/nomad/helper/args"
	"github.com/hashicorp/nomad/helper/uuid"
	"github.com/hashicorp/nomad/lib/kheap"
	psstructs "github.com/hashicorp/nomad/plugins/shared/structs"
	"github.com/mitchellh/copystructure"
	"github.com/ugorji/go/codec"
	"golang.org/x/crypto/blake2b"
)

var (
	// validPolicyName is used to validate a policy name
	validPolicyName = regexp.MustCompile("^[a-zA-Z0-9-]{1,128}$")

	// b32 is a lowercase base32 encoding for use in URL friendly service hashes
	b32 = base32.NewEncoding(strings.ToLower("abcdefghijklmnopqrstuvwxyz234567"))
)

type MessageType uint8

const (
	NodeRegisterRequestType MessageType = iota
	NodeDeregisterRequestType
	NodeUpdateStatusRequestType
	NodeUpdateDrainRequestType
	JobRegisterRequestType
	JobDeregisterRequestType
	EvalUpdateRequestType
	EvalDeleteRequestType
	AllocUpdateRequestType
	AllocClientUpdateRequestType
	ReconcileJobSummariesRequestType
	VaultAccessorRegisterRequestType
	VaultAccessorDeregisterRequestType
	ApplyPlanResultsRequestType
	DeploymentStatusUpdateRequestType
	DeploymentPromoteRequestType
	DeploymentAllocHealthRequestType
	DeploymentDeleteRequestType
	JobStabilityRequestType
	ACLPolicyUpsertRequestType
	ACLPolicyDeleteRequestType
	ACLTokenUpsertRequestType
	ACLTokenDeleteRequestType
	ACLTokenBootstrapRequestType
	AutopilotRequestType
	UpsertNodeEventsType
	JobBatchDeregisterRequestType
	AllocUpdateDesiredTransitionRequestType
	NodeUpdateEligibilityRequestType
	BatchNodeUpdateDrainRequestType
	SchedulerConfigRequestType
)

const (
	// IgnoreUnknownTypeFlag is set along with a MessageType
	// to indicate that the message type can be safely ignored
	// if it is not recognized. This is for future proofing, so
	// that new commands can be added in a way that won't cause
	// old servers to crash when the FSM attempts to process them.
	IgnoreUnknownTypeFlag MessageType = 128

	// ApiMajorVersion is returned as part of the Status.Version request.
	// It should be incremented anytime the APIs are changed in a way
	// that would break clients for sane client versioning.
	ApiMajorVersion = 1

	// ApiMinorVersion is returned as part of the Status.Version request.
	// It should be incremented anytime the APIs are changed to allow
	// for sane client versioning. Minor changes should be compatible
	// within the major version.
	ApiMinorVersion = 1

	ProtocolVersion = "protocol"
	APIMajorVersion = "api.major"
	APIMinorVersion = "api.minor"

	GetterModeAny  = "any"
	GetterModeFile = "file"
	GetterModeDir  = "dir"

	// maxPolicyDescriptionLength limits a policy description length
	maxPolicyDescriptionLength = 256

	// maxTokenNameLength limits a ACL token name length
	maxTokenNameLength = 256

	// ACLClientToken and ACLManagementToken are the only types of tokens
	ACLClientToken     = "client"
	ACLManagementToken = "management"

	// DefaultNamespace is the default namespace.
	DefaultNamespace            = "default"
	DefaultNamespaceDescription = "Default shared namespace"

	// JitterFraction is a the limit to the amount of jitter we apply
	// to a user specified MaxQueryTime. We divide the specified time by
	// the fraction. So 16 == 6.25% limit of jitter. This jitter is also
	// applied to RPCHoldTimeout.
	JitterFraction = 16

	// MaxRetainedNodeEvents is the maximum number of node events that will be
	// retained for a single node
	MaxRetainedNodeEvents = 10

	// MaxRetainedNodeScores is the number of top scoring nodes for which we
	// retain scoring metadata
	MaxRetainedNodeScores = 5

	// Normalized scorer name
	NormScorerName = "normalized-score"
)

// Context defines the scope in which a search for Nomad object operates, and
// is also used to query the matching index value for this context
type Context string

const (
	Allocs      Context = "allocs"
	Deployments Context = "deployment"
	Evals       Context = "evals"
	Jobs        Context = "jobs"
	Nodes       Context = "nodes"
	Namespaces  Context = "namespaces"
	Quotas      Context = "quotas"
	All         Context = "all"
)

// NamespacedID is a tuple of an ID and a namespace
type NamespacedID struct {
	ID        string
	Namespace string
}

// NewNamespacedID returns a new namespaced ID given the ID and namespace
func NewNamespacedID(id, ns string) NamespacedID {
	return NamespacedID{
		ID:        id,
		Namespace: ns,
	}
}

func (n NamespacedID) String() string {
	return fmt.Sprintf("<ns: %q, id: %q>", n.Namespace, n.ID)
}

// RPCInfo is used to describe common information about query
type RPCInfo interface {
	RequestRegion() string
	IsRead() bool
	AllowStaleRead() bool
	IsForwarded() bool
	SetForwarded()
}

// InternalRpcInfo allows adding internal RPC metadata to an RPC. This struct
// should NOT be replicated in the API package as it is internal only.
type InternalRpcInfo struct {
	// Forwarded marks whether the RPC has been forwarded.
	Forwarded bool
}

// IsForwarded returns whether the RPC is forwarded from another server.
func (i *InternalRpcInfo) IsForwarded() bool {
	return i.Forwarded
}

// SetForwarded marks that the RPC is being forwarded from another server.
func (i *InternalRpcInfo) SetForwarded() {
	i.Forwarded = true
}

// QueryOptions is used to specify various flags for read queries
type QueryOptions struct {
	// The target region for this query
	Region string

	// Namespace is the target namespace for the query.
	Namespace string

	// If set, wait until query exceeds given index. Must be provided
	// with MaxQueryTime.
	MinQueryIndex uint64

	// Provided with MinQueryIndex to wait for change.
	MaxQueryTime time.Duration

	// If set, any follower can service the request. Results
	// may be arbitrarily stale.
	AllowStale bool

	// If set, used as prefix for resource list searches
	Prefix string

	// AuthToken is secret portion of the ACL token used for the request
	AuthToken string

	InternalRpcInfo
}

func (q QueryOptions) RequestRegion() string {
	return q.Region
}

func (q QueryOptions) RequestNamespace() string {
	if q.Namespace == "" {
		return DefaultNamespace
	}
	return q.Namespace
}

// QueryOption only applies to reads, so always true
func (q QueryOptions) IsRead() bool {
	return true
}

func (q QueryOptions) AllowStaleRead() bool {
	return q.AllowStale
}

type WriteRequest struct {
	// The target region for this write
	Region string

	// Namespace is the target namespace for the write.
	Namespace string

	// AuthToken is secret portion of the ACL token used for the request
	AuthToken string

	InternalRpcInfo
}

func (w WriteRequest) RequestRegion() string {
	// The target region for this request
	return w.Region
}

func (w WriteRequest) RequestNamespace() string {
	if w.Namespace == "" {
		return DefaultNamespace
	}
	return w.Namespace
}

// WriteRequest only applies to writes, always false
func (w WriteRequest) IsRead() bool {
	return false
}

func (w WriteRequest) AllowStaleRead() bool {
	return false
}

// QueryMeta allows a query response to include potentially
// useful metadata about a query
type QueryMeta struct {
	// This is the index associated with the read
	Index uint64

	// If AllowStale is used, this is time elapsed since
	// last contact between the follower and leader. This
	// can be used to gauge staleness.
	LastContact time.Duration

	// Used to indicate if there is a known leader node
	KnownLeader bool
}

// WriteMeta allows a write response to include potentially
// useful metadata about the write
type WriteMeta struct {
	// This is the index associated with the write
	Index uint64
}

// NodeRegisterRequest is used for Node.Register endpoint
// to register a node as being a schedulable entity.
type NodeRegisterRequest struct {
	Node      *Node
	NodeEvent *NodeEvent
	WriteRequest
}

// NodeDeregisterRequest is used for Node.Deregister endpoint
// to deregister a node as being a schedulable entity.
type NodeDeregisterRequest struct {
	NodeID string
	WriteRequest
}

// NodeServerInfo is used to in NodeUpdateResponse to return Nomad server
// information used in RPC server lists.
type NodeServerInfo struct {
	// RPCAdvertiseAddr is the IP endpoint that a Nomad Server wishes to
	// be contacted at for RPCs.
	RPCAdvertiseAddr string

	// RpcMajorVersion is the major version number the Nomad Server
	// supports
	RPCMajorVersion int32

	// RpcMinorVersion is the minor version number the Nomad Server
	// supports
	RPCMinorVersion int32

	// Datacenter is the datacenter that a Nomad server belongs to
	Datacenter string
}

// NodeUpdateStatusRequest is used for Node.UpdateStatus endpoint
// to update the status of a node.
type NodeUpdateStatusRequest struct {
	NodeID    string
	Status    string
	NodeEvent *NodeEvent
	WriteRequest
}

// NodeUpdateDrainRequest is used for updating the drain strategy
type NodeUpdateDrainRequest struct {
	NodeID        string
	DrainStrategy *DrainStrategy

	// COMPAT Remove in version 0.10
	// As part of Nomad 0.8 we have deprecated the drain boolean in favor of a
	// drain strategy but we need to handle the upgrade path where the Raft log
	// contains drain updates with just the drain boolean being manipulated.
	Drain bool

	// MarkEligible marks the node as eligible if removing the drain strategy.
	MarkEligible bool

	// NodeEvent is the event added to the node
	NodeEvent *NodeEvent

	WriteRequest
}

// BatchNodeUpdateDrainRequest is used for updating the drain strategy for a
// batch of nodes
type BatchNodeUpdateDrainRequest struct {
	// Updates is a mapping of nodes to their updated drain strategy
	Updates map[string]*DrainUpdate

	// NodeEvents is a mapping of the node to the event to add to the node
	NodeEvents map[string]*NodeEvent

	WriteRequest
}

// DrainUpdate is used to update the drain of a node
type DrainUpdate struct {
	// DrainStrategy is the new strategy for the node
	DrainStrategy *DrainStrategy

	// MarkEligible marks the node as eligible if removing the drain strategy.
	MarkEligible bool
}

// NodeUpdateEligibilityRequest is used for updating the scheduling	eligibility
type NodeUpdateEligibilityRequest struct {
	NodeID      string
	Eligibility string

	// NodeEvent is the event added to the node
	NodeEvent *NodeEvent

	WriteRequest
}

// NodeEvaluateRequest is used to re-evaluate the node
type NodeEvaluateRequest struct {
	NodeID string
	WriteRequest
}

// NodeSpecificRequest is used when we just need to specify a target node
type NodeSpecificRequest struct {
	NodeID   string
	SecretID string
	QueryOptions
}

// SearchResponse is used to return matches and information about whether
// the match list is truncated specific to each type of context.
type SearchResponse struct {
	// Map of context types to ids which match a specified prefix
	Matches map[Context][]string

	// Truncations indicates whether the matches for a particular context have
	// been truncated
	Truncations map[Context]bool

	QueryMeta
}

// SearchRequest is used to parameterize a request, and returns a
// list of matches made up of jobs, allocations, evaluations, and/or nodes,
// along with whether or not the information returned is truncated.
type SearchRequest struct {
	// Prefix is what ids are matched to. I.e, if the given prefix were
	// "a", potential matches might be "abcd" or "aabb"
	Prefix string

	// Context is the type that can be matched against. A context can be a job,
	// node, evaluation, allocation, or empty (indicated every context should be
	// matched)
	Context Context

	QueryOptions
}

// JobRegisterRequest is used for Job.Register endpoint
// to register a job as being a schedulable entity.
type JobRegisterRequest struct {
	Job *Job

	// If EnforceIndex is set then the job will only be registered if the passed
	// JobModifyIndex matches the current Jobs index. If the index is zero, the
	// register only occurs if the job is new.
	EnforceIndex   bool
	JobModifyIndex uint64

	// PolicyOverride is set when the user is attempting to override any policies
	PolicyOverride bool

	WriteRequest
}

// JobDeregisterRequest is used for Job.Deregister endpoint
// to deregister a job as being a schedulable entity.
type JobDeregisterRequest struct {
	JobID string

	// Purge controls whether the deregister purges the job from the system or
	// whether the job is just marked as stopped and will be removed by the
	// garbage collector
	Purge bool

	WriteRequest
}

// JobBatchDeregisterRequest is used to batch deregister jobs and upsert
// evaluations.
type JobBatchDeregisterRequest struct {
	// Jobs is the set of jobs to deregister
	Jobs map[NamespacedID]*JobDeregisterOptions

	// Evals is the set of evaluations to create.
	Evals []*Evaluation

	WriteRequest
}

// JobDeregisterOptions configures how a job is deregistered.
type JobDeregisterOptions struct {
	// Purge controls whether the deregister purges the job from the system or
	// whether the job is just marked as stopped and will be removed by the
	// garbage collector
	Purge bool
}

// JobEvaluateRequest is used when we just need to re-evaluate a target job
type JobEvaluateRequest struct {
	JobID       string
	EvalOptions EvalOptions
	WriteRequest
}

// EvalOptions is used to encapsulate options when forcing a job evaluation
type EvalOptions struct {
	ForceReschedule bool
}

// JobSpecificRequest is used when we just need to specify a target job
type JobSpecificRequest struct {
	JobID     string
	AllAllocs bool
	QueryOptions
}

// JobListRequest is used to parameterize a list request
type JobListRequest struct {
	QueryOptions
}

// JobPlanRequest is used for the Job.Plan endpoint to trigger a dry-run
// evaluation of the Job.
type JobPlanRequest struct {
	Job  *Job
	Diff bool // Toggles an annotated diff
	// PolicyOverride is set when the user is attempting to override any policies
	PolicyOverride bool
	WriteRequest
}

// JobSummaryRequest is used when we just need to get a specific job summary
type JobSummaryRequest struct {
	JobID string
	QueryOptions
}

// JobDispatchRequest is used to dispatch a job based on a parameterized job
type JobDispatchRequest struct {
	JobID   string
	Payload []byte
	Meta    map[string]string
	WriteRequest
}

// JobValidateRequest is used to validate a job
type JobValidateRequest struct {
	Job *Job
	WriteRequest
}

// JobRevertRequest is used to revert a job to a prior version.
type JobRevertRequest struct {
	// JobID is the ID of the job  being reverted
	JobID string

	// JobVersion the version to revert to.
	JobVersion uint64

	// EnforcePriorVersion if set will enforce that the job is at the given
	// version before reverting.
	EnforcePriorVersion *uint64

	WriteRequest
}

// JobStabilityRequest is used to marked a job as stable.
type JobStabilityRequest struct {
	// Job to set the stability on
	JobID      string
	JobVersion uint64

	// Set the stability
	Stable bool
	WriteRequest
}

// JobStabilityResponse is the response when marking a job as stable.
type JobStabilityResponse struct {
	WriteMeta
}

// NodeListRequest is used to parameterize a list request
type NodeListRequest struct {
	QueryOptions
}

// EvalUpdateRequest is used for upserting evaluations.
type EvalUpdateRequest struct {
	Evals     []*Evaluation
	EvalToken string
	WriteRequest
}

// EvalDeleteRequest is used for deleting an evaluation.
type EvalDeleteRequest struct {
	Evals  []string
	Allocs []string
	WriteRequest
}

// EvalSpecificRequest is used when we just need to specify a target evaluation
type EvalSpecificRequest struct {
	EvalID string
	QueryOptions
}

// EvalAckRequest is used to Ack/Nack a specific evaluation
type EvalAckRequest struct {
	EvalID string
	Token  string
	WriteRequest
}

// EvalDequeueRequest is used when we want to dequeue an evaluation
type EvalDequeueRequest struct {
	Schedulers       []string
	Timeout          time.Duration
	SchedulerVersion uint16
	WriteRequest
}

// EvalListRequest is used to list the evaluations
type EvalListRequest struct {
	QueryOptions
}

// PlanRequest is used to submit an allocation plan to the leader
type PlanRequest struct {
	Plan *Plan
	WriteRequest
}

// ApplyPlanResultsRequest is used by the planner to apply a Raft transaction
// committing the result of a plan.
type ApplyPlanResultsRequest struct {
	// AllocUpdateRequest holds the allocation updates to be made by the
	// scheduler.
	AllocUpdateRequest

	// Deployment is the deployment created or updated as a result of a
	// scheduling event.
	Deployment *Deployment

	// DeploymentUpdates is a set of status updates to apply to the given
	// deployments. This allows the scheduler to cancel any unneeded deployment
	// because the job is stopped or the update block is removed.
	DeploymentUpdates []*DeploymentStatusUpdate

	// EvalID is the eval ID of the plan being applied. The modify index of the
	// evaluation is updated as part of applying the plan to ensure that subsequent
	// scheduling events for the same job will wait for the index that last produced
	// state changes. This is necessary for blocked evaluations since they can be
	// processed many times, potentially making state updates, without the state of
	// the evaluation itself being updated.
	EvalID string

	// NodePreemptions is a slice of allocations from other lower priority jobs
	// that are preempted. Preempted allocations are marked as evicted.
	NodePreemptions []*Allocation

	// PreemptionEvals is a slice of follow up evals for jobs whose allocations
	// have been preempted to place allocs in this plan
	PreemptionEvals []*Evaluation
}

// AllocUpdateRequest is used to submit changes to allocations, either
// to cause evictions or to assign new allocations. Both can be done
// within a single transaction
type AllocUpdateRequest struct {
	// Alloc is the list of new allocations to assign
	Alloc []*Allocation

	// Evals is the list of new evaluations to create
	// Evals are valid only when used in the Raft RPC
	Evals []*Evaluation

	// Job is the shared parent job of the allocations.
	// It is pulled out since it is common to reduce payload size.
	Job *Job

	WriteRequest
}

// AllocUpdateDesiredTransitionRequest is used to submit changes to allocations
// desired transition state.
type AllocUpdateDesiredTransitionRequest struct {
	// Allocs is the mapping of allocation ids to their desired state
	// transition
	Allocs map[string]*DesiredTransition

	// Evals is the set of evaluations to create
	Evals []*Evaluation

	WriteRequest
}

// AllocListRequest is used to request a list of allocations
type AllocListRequest struct {
	QueryOptions
}

// AllocSpecificRequest is used to query a specific allocation
type AllocSpecificRequest struct {
	AllocID string
	QueryOptions
}

// AllocsGetRequest is used to query a set of allocations
type AllocsGetRequest struct {
	AllocIDs []string
	QueryOptions
}

// PeriodicForceRequest is used to force a specific periodic job.
type PeriodicForceRequest struct {
	JobID string
	WriteRequest
}

// ServerMembersResponse has the list of servers in a cluster
type ServerMembersResponse struct {
	ServerName   string
	ServerRegion string
	ServerDC     string
	Members      []*ServerMember
}

// ServerMember holds information about a Nomad server agent in a cluster
type ServerMember struct {
	Name        string
	Addr        net.IP
	Port        uint16
	Tags        map[string]string
	Status      string
	ProtocolMin uint8
	ProtocolMax uint8
	ProtocolCur uint8
	DelegateMin uint8
	DelegateMax uint8
	DelegateCur uint8
}

// DeriveVaultTokenRequest is used to request wrapped Vault tokens for the
// following tasks in the given allocation
type DeriveVaultTokenRequest struct {
	NodeID   string
	SecretID string
	AllocID  string
	Tasks    []string
	QueryOptions
}

// VaultAccessorsRequest is used to operate on a set of Vault accessors
type VaultAccessorsRequest struct {
	Accessors []*VaultAccessor
}

// VaultAccessor is a reference to a created Vault token on behalf of
// an allocation's task.
type VaultAccessor struct {
	AllocID     string
	Task        string
	NodeID      string
	Accessor    string
	CreationTTL int

	// Raft Indexes
	CreateIndex uint64
}

// DeriveVaultTokenResponse returns the wrapped tokens for each requested task
type DeriveVaultTokenResponse struct {
	// Tasks is a mapping between the task name and the wrapped token
	Tasks map[string]string

	// Error stores any error that occurred. Errors are stored here so we can
	// communicate whether it is retriable
	Error *RecoverableError

	QueryMeta
}

// GenericRequest is used to request where no
// specific information is needed.
type GenericRequest struct {
	QueryOptions
}

// DeploymentListRequest is used to list the deployments
type DeploymentListRequest struct {
	QueryOptions
}

// DeploymentDeleteRequest is used for deleting deployments.
type DeploymentDeleteRequest struct {
	Deployments []string
	WriteRequest
}

// DeploymentStatusUpdateRequest is used to update the status of a deployment as
// well as optionally creating an evaluation atomically.
type DeploymentStatusUpdateRequest struct {
	// Eval, if set, is used to create an evaluation at the same time as
	// updating the status of a deployment.
	Eval *Evaluation

	// DeploymentUpdate is a status update to apply to the given
	// deployment.
	DeploymentUpdate *DeploymentStatusUpdate

	// Job is used to optionally upsert a job. This is used when setting the
	// allocation health results in a deployment failure and the deployment
	// auto-reverts to the latest stable job.
	Job *Job
}

// DeploymentAllocHealthRequest is used to set the health of a set of
// allocations as part of a deployment.
type DeploymentAllocHealthRequest struct {
	DeploymentID string

	// Marks these allocations as healthy, allow further allocations
	// to be rolled.
	HealthyAllocationIDs []string

	// Any unhealthy allocations fail the deployment
	UnhealthyAllocationIDs []string

	WriteRequest
}

// ApplyDeploymentAllocHealthRequest is used to apply an alloc health request via Raft
type ApplyDeploymentAllocHealthRequest struct {
	DeploymentAllocHealthRequest

	// Timestamp is the timestamp to use when setting the allocations health.
	Timestamp time.Time

	// An optional field to update the status of a deployment
	DeploymentUpdate *DeploymentStatusUpdate

	// Job is used to optionally upsert a job. This is used when setting the
	// allocation health results in a deployment failure and the deployment
	// auto-reverts to the latest stable job.
	Job *Job

	// An optional evaluation to create after promoting the canaries
	Eval *Evaluation
}

// DeploymentPromoteRequest is used to promote task groups in a deployment
type DeploymentPromoteRequest struct {
	DeploymentID string

	// All is to promote all task groups
	All bool

	// Groups is used to set the promotion status per task group
	Groups []string

	WriteRequest
}

// ApplyDeploymentPromoteRequest is used to apply a promotion request via Raft
type ApplyDeploymentPromoteRequest struct {
	DeploymentPromoteRequest

	// An optional evaluation to create after promoting the canaries
	Eval *Evaluation
}

// DeploymentPauseRequest is used to pause a deployment
type DeploymentPauseRequest struct {
	DeploymentID string

	// Pause sets the pause status
	Pause bool

	WriteRequest
}

// DeploymentSpecificRequest is used to make a request specific to a particular
// deployment
type DeploymentSpecificRequest struct {
	DeploymentID string
	QueryOptions
}

// DeploymentFailRequest is used to fail a particular deployment
type DeploymentFailRequest struct {
	DeploymentID string
	WriteRequest
}

// SingleDeploymentResponse is used to respond with a single deployment
type SingleDeploymentResponse struct {
	Deployment *Deployment
	QueryMeta
}

// GenericResponse is used to respond to a request where no
// specific response information is needed.
type GenericResponse struct {
	WriteMeta
}

// VersionResponse is used for the Status.Version response
type VersionResponse struct {
	Build    string
	Versions map[string]int
	QueryMeta
}

// JobRegisterResponse is used to respond to a job registration
type JobRegisterResponse struct {
	EvalID          string
	EvalCreateIndex uint64
	JobModifyIndex  uint64

	// Warnings contains any warnings about the given job. These may include
	// deprecation warnings.
	Warnings string

	QueryMeta
}

// JobDeregisterResponse is used to respond to a job deregistration
type JobDeregisterResponse struct {
	EvalID          string
	EvalCreateIndex uint64
	JobModifyIndex  uint64
	QueryMeta
}

// JobBatchDeregisterResponse is used to respond to a batch job deregistration
type JobBatchDeregisterResponse struct {
	// JobEvals maps the job to its created evaluation
	JobEvals map[NamespacedID]string
	QueryMeta
}

// JobValidateResponse is the response from validate request
type JobValidateResponse struct {
	// DriverConfigValidated indicates whether the agent validated the driver
	// config
	DriverConfigValidated bool

	// ValidationErrors is a list of validation errors
	ValidationErrors []string

	// Error is a string version of any error that may have occurred
	Error string

	// Warnings contains any warnings about the given job. These may include
	// deprecation warnings.
	Warnings string
}

// NodeUpdateResponse is used to respond to a node update
type NodeUpdateResponse struct {
	HeartbeatTTL    time.Duration
	EvalIDs         []string
	EvalCreateIndex uint64
	NodeModifyIndex uint64

	// LeaderRPCAddr is the RPC address of the current Raft Leader.  If
	// empty, the current Nomad Server is in the minority of a partition.
	LeaderRPCAddr string

	// NumNodes is the number of Nomad nodes attached to this quorum of
	// Nomad Servers at the time of the response.  This value can
	// fluctuate based on the health of the cluster between heartbeats.
	NumNodes int32

	// Servers is the full list of known Nomad servers in the local
	// region.
	Servers []*NodeServerInfo

	QueryMeta
}

// NodeDrainUpdateResponse is used to respond to a node drain update
type NodeDrainUpdateResponse struct {
	NodeModifyIndex uint64
	EvalIDs         []string
	EvalCreateIndex uint64
	WriteMeta
}

// NodeEligibilityUpdateResponse is used to respond to a node eligibility update
type NodeEligibilityUpdateResponse struct {
	NodeModifyIndex uint64
	EvalIDs         []string
	EvalCreateIndex uint64
	WriteMeta
}

// NodeAllocsResponse is used to return allocs for a single node
type NodeAllocsResponse struct {
	Allocs []*Allocation
	QueryMeta
}

// NodeClientAllocsResponse is used to return allocs meta data for a single node
type NodeClientAllocsResponse struct {
	Allocs map[string]uint64

	// MigrateTokens are used when ACLs are enabled to allow cross node,
	// authenticated access to sticky volumes
	MigrateTokens map[string]string

	QueryMeta
}

// SingleNodeResponse is used to return a single node
type SingleNodeResponse struct {
	Node *Node
	QueryMeta
}

// NodeListResponse is used for a list request
type NodeListResponse struct {
	Nodes []*NodeListStub
	QueryMeta
}

// SingleJobResponse is used to return a single job
type SingleJobResponse struct {
	Job *Job
	QueryMeta
}

// JobSummaryResponse is used to return a single job summary
type JobSummaryResponse struct {
	JobSummary *JobSummary
	QueryMeta
}

type JobDispatchResponse struct {
	DispatchedJobID string
	EvalID          string
	EvalCreateIndex uint64
	JobCreateIndex  uint64
	WriteMeta
}

// JobListResponse is used for a list request
type JobListResponse struct {
	Jobs []*JobListStub
	QueryMeta
}

// JobVersionsRequest is used to get a jobs versions
type JobVersionsRequest struct {
	JobID string
	Diffs bool
	QueryOptions
}

// JobVersionsResponse is used for a job get versions request
type JobVersionsResponse struct {
	Versions []*Job
	Diffs    []*JobDiff
	QueryMeta
}

// JobPlanResponse is used to respond to a job plan request
type JobPlanResponse struct {
	// Annotations stores annotations explaining decisions the scheduler made.
	Annotations *PlanAnnotations

	// FailedTGAllocs is the placement failures per task group.
	FailedTGAllocs map[string]*AllocMetric

	// JobModifyIndex is the modification index of the job. The value can be
	// used when running `nomad run` to ensure that the Job wasn’t modified
	// since the last plan. If the job is being created, the value is zero.
	JobModifyIndex uint64

	// CreatedEvals is the set of evaluations created by the scheduler. The
	// reasons for this can be rolling-updates or blocked evals.
	CreatedEvals []*Evaluation

	// Diff contains the diff of the job and annotations on whether the change
	// causes an in-place update or create/destroy
	Diff *JobDiff

	// NextPeriodicLaunch is the time duration till the job would be launched if
	// submitted.
	NextPeriodicLaunch time.Time

	// Warnings contains any warnings about the given job. These may include
	// deprecation warnings.
	Warnings string

	WriteMeta
}

// SingleAllocResponse is used to return a single allocation
type SingleAllocResponse struct {
	Alloc *Allocation
	QueryMeta
}

// AllocsGetResponse is used to return a set of allocations
type AllocsGetResponse struct {
	Allocs []*Allocation
	QueryMeta
}

// JobAllocationsResponse is used to return the allocations for a job
type JobAllocationsResponse struct {
	Allocations []*AllocListStub
	QueryMeta
}

// JobEvaluationsResponse is used to return the evaluations for a job
type JobEvaluationsResponse struct {
	Evaluations []*Evaluation
	QueryMeta
}

// SingleEvalResponse is used to return a single evaluation
type SingleEvalResponse struct {
	Eval *Evaluation
	QueryMeta
}

// EvalDequeueResponse is used to return from a dequeue
type EvalDequeueResponse struct {
	Eval  *Evaluation
	Token string

	// WaitIndex is the Raft index the worker should wait until invoking the
	// scheduler.
	WaitIndex uint64

	QueryMeta
}

// GetWaitIndex is used to retrieve the Raft index in which state should be at
// or beyond before invoking the scheduler.
func (e *EvalDequeueResponse) GetWaitIndex() uint64 {
	// Prefer the wait index sent. This will be populated on all responses from
	// 0.7.0 and above
	if e.WaitIndex != 0 {
		return e.WaitIndex
	} else if e.Eval != nil {
		return e.Eval.ModifyIndex
	}

	// This should never happen
	return 1
}

// PlanResponse is used to return from a PlanRequest
type PlanResponse struct {
	Result *PlanResult
	WriteMeta
}

// AllocListResponse is used for a list request
type AllocListResponse struct {
	Allocations []*AllocListStub
	QueryMeta
}

// DeploymentListResponse is used for a list request
type DeploymentListResponse struct {
	Deployments []*Deployment
	QueryMeta
}

// EvalListResponse is used for a list request
type EvalListResponse struct {
	Evaluations []*Evaluation
	QueryMeta
}

// EvalAllocationsResponse is used to return the allocations for an evaluation
type EvalAllocationsResponse struct {
	Allocations []*AllocListStub
	QueryMeta
}

// PeriodicForceResponse is used to respond to a periodic job force launch
type PeriodicForceResponse struct {
	EvalID          string
	EvalCreateIndex uint64
	WriteMeta
}

// DeploymentUpdateResponse is used to respond to a deployment change. The
// response will include the modify index of the deployment as well as details
// of any triggered evaluation.
type DeploymentUpdateResponse struct {
	EvalID                string
	EvalCreateIndex       uint64
	DeploymentModifyIndex uint64

	// RevertedJobVersion is the version the job was reverted to. If unset, the
	// job wasn't reverted
	RevertedJobVersion *uint64

	WriteMeta
}

// NodeConnQueryResponse is used to respond to a query of whether a server has
// a connection to a specific Node
type NodeConnQueryResponse struct {
	// Connected indicates whether a connection to the Client exists
	Connected bool

	// Established marks the time at which the connection was established
	Established time.Time

	QueryMeta
}

// EmitNodeEventsRequest is a request to update the node events source
// with a new client-side event
type EmitNodeEventsRequest struct {
	// NodeEvents are a map where the key is a node id, and value is a list of
	// events for that node
	NodeEvents map[string][]*NodeEvent

	WriteRequest
}

// EmitNodeEventsResponse is a response to the client about the status of
// the node event source update.
type EmitNodeEventsResponse struct {
	Index uint64
	WriteMeta
}

const (
	NodeEventSubsystemDrain     = "Drain"
	NodeEventSubsystemDriver    = "Driver"
	NodeEventSubsystemHeartbeat = "Heartbeat"
	NodeEventSubsystemCluster   = "Cluster"
)

// NodeEvent is a single unit representing a node’s state change
type NodeEvent struct {
	Message     string
	Subsystem   string
	Details     map[string]string
	Timestamp   time.Time
	CreateIndex uint64
}

func (ne *NodeEvent) String() string {
	var details []string
	for k, v := range ne.Details {
		details = append(details, fmt.Sprintf("%s: %s", k, v))
	}

	return fmt.Sprintf("Message: %s, Subsystem: %s, Details: %s, Timestamp: %s", ne.Message, ne.Subsystem, strings.Join(details, ","), ne.Timestamp.String())
}

func (ne *NodeEvent) Copy() *NodeEvent {
	c := new(NodeEvent)
	*c = *ne
	c.Details = helper.CopyMapStringString(ne.Details)
	return c
}

// NewNodeEvent generates a new node event storing the current time as the
// timestamp
func NewNodeEvent() *NodeEvent {
	return &NodeEvent{Timestamp: time.Now()}
}

// SetMessage is used to set the message on the node event
func (ne *NodeEvent) SetMessage(msg string) *NodeEvent {
	ne.Message = msg
	return ne
}

// SetSubsystem is used to set the subsystem on the node event
func (ne *NodeEvent) SetSubsystem(sys string) *NodeEvent {
	ne.Subsystem = sys
	return ne
}

// SetTimestamp is used to set the timestamp on the node event
func (ne *NodeEvent) SetTimestamp(ts time.Time) *NodeEvent {
	ne.Timestamp = ts
	return ne
}

// AddDetail is used to add a detail to the node event
func (ne *NodeEvent) AddDetail(k, v string) *NodeEvent {
	if ne.Details == nil {
		ne.Details = make(map[string]string, 1)
	}
	ne.Details[k] = v
	return ne
}

const (
	NodeStatusInit  = "initializing"
	NodeStatusReady = "ready"
	NodeStatusDown  = "down"
)

// ShouldDrainNode checks if a given node status should trigger an
// evaluation. Some states don't require any further action.
func ShouldDrainNode(status string) bool {
	switch status {
	case NodeStatusInit, NodeStatusReady:
		return false
	case NodeStatusDown:
		return true
	default:
		panic(fmt.Sprintf("unhandled node status %s", status))
	}
}

// ValidNodeStatus is used to check if a node status is valid
func ValidNodeStatus(status string) bool {
	switch status {
	case NodeStatusInit, NodeStatusReady, NodeStatusDown:
		return true
	default:
		return false
	}
}

const (
	// NodeSchedulingEligible and Ineligible marks the node as eligible or not,
	// respectively, for receiving allocations. This is orthoginal to the node
	// status being ready.
	NodeSchedulingEligible   = "eligible"
	NodeSchedulingIneligible = "ineligible"
)

// DrainSpec describes a Node's desired drain behavior.
type DrainSpec struct {
	// Deadline is the duration after StartTime when the remaining
	// allocations on a draining Node should be told to stop.
	Deadline time.Duration

	// IgnoreSystemJobs allows systems jobs to remain on the node even though it
	// has been marked for draining.
	IgnoreSystemJobs bool
}

// DrainStrategy describes a Node's drain behavior.
type DrainStrategy struct {
	// DrainSpec is the user declared drain specification
	DrainSpec

	// ForceDeadline is the deadline time for the drain after which drains will
	// be forced
	ForceDeadline time.Time
}

func (d *DrainStrategy) Copy() *DrainStrategy {
	if d == nil {
		return nil
	}

	nd := new(DrainStrategy)
	*nd = *d
	return nd
}

// DeadlineTime returns a boolean whether the drain strategy allows an infinite
// duration or otherwise the deadline time. The force drain is captured by the
// deadline time being in the past.
func (d *DrainStrategy) DeadlineTime() (infinite bool, deadline time.Time) {
	// Treat the nil case as a force drain so during an upgrade where a node may
	// not have a drain strategy but has Drain set to true, it is treated as a
	// force to mimick old behavior.
	if d == nil {
		return false, time.Time{}
	}

	ns := d.Deadline.Nanoseconds()
	switch {
	case ns < 0: // Force
		return false, time.Time{}
	case ns == 0: // Infinite
		return true, time.Time{}
	default:
		return false, d.ForceDeadline
	}
}

func (d *DrainStrategy) Equal(o *DrainStrategy) bool {
	if d == nil && o == nil {
		return true
	} else if o != nil && d == nil {
		return false
	} else if d != nil && o == nil {
		return false
	}

	// Compare values
	if d.ForceDeadline != o.ForceDeadline {
		return false
	} else if d.Deadline != o.Deadline {
		return false
	} else if d.IgnoreSystemJobs != o.IgnoreSystemJobs {
		return false
	}

	return true
}

// Node is a representation of a schedulable client node
type Node struct {
	// ID is a unique identifier for the node. It can be constructed
	// by doing a concatenation of the Name and Datacenter as a simple
	// approach. Alternatively a UUID may be used.
	ID string

	// SecretID is an ID that is only known by the Node and the set of Servers.
	// It is not accessible via the API and is used to authenticate nodes
	// conducting privileged activities.
	SecretID string

	// Datacenter for this node
	Datacenter string

	// Node name
	Name string

	// HTTPAddr is the address on which the Nomad client is listening for http
	// requests
	HTTPAddr string

	// TLSEnabled indicates if the Agent has TLS enabled for the HTTP API
	TLSEnabled bool

	// Attributes is an arbitrary set of key/value
	// data that can be used for constraints. Examples
	// include "kernel.name=linux", "arch=386", "driver.docker=1",
	// "docker.runtime=1.8.3"
	Attributes map[string]string

	// NodeResources captures the available resources on the client.
	NodeResources *NodeResources

	// ReservedResources captures the set resources on the client that are
	// reserved from scheduling.
	ReservedResources *NodeReservedResources

	// Resources is the available resources on the client.
	// For example 'cpu=2' 'memory=2048'
	// COMPAT(0.10): Remove in 0.10
	Resources *Resources

	// Reserved is the set of resources that are reserved,
	// and should be subtracted from the total resources for
	// the purposes of scheduling. This may be provide certain
	// high-watermark tolerances or because of external schedulers
	// consuming resources.
	Reserved *Resources

	// Links are used to 'link' this client to external
	// systems. For example 'consul=foo.dc1' 'aws=i-83212'
	// 'ami=ami-123'
	Links map[string]string

	// Meta is used to associate arbitrary metadata with this
	// client. This is opaque to Nomad.
	Meta map[string]string

	// NodeClass is an opaque identifier used to group nodes
	// together for the purpose of determining scheduling pressure.
	NodeClass string

	// ComputedClass is a unique id that identifies nodes with a common set of
	// attributes and capabilities.
	ComputedClass string

	// COMPAT: Remove in Nomad 0.9
	// Drain is controlled by the servers, and not the client.
	// If true, no jobs will be scheduled to this node, and existing
	// allocations will be drained. Superceded by DrainStrategy in Nomad
	// 0.8 but kept for backward compat.
	Drain bool

	// DrainStrategy determines the node's draining behavior. Will be nil
	// when Drain=false.
	DrainStrategy *DrainStrategy

	// SchedulingEligibility determines whether this node will receive new
	// placements.
	SchedulingEligibility string

	// Status of this node
	Status string

	// StatusDescription is meant to provide more human useful information
	StatusDescription string

	// StatusUpdatedAt is the time stamp at which the state of the node was
	// updated
	StatusUpdatedAt int64

	// Events is the most recent set of events generated for the node,
	// retaining only MaxRetainedNodeEvents number at a time
	Events []*NodeEvent

	// Drivers is a map of driver names to current driver information
	Drivers map[string]*DriverInfo

	// Raft Indexes
	CreateIndex uint64
	ModifyIndex uint64
}

// Ready returns true if the node is ready for running allocations
func (n *Node) Ready() bool {
	// Drain is checked directly to support pre-0.8 Node data
	return n.Status == NodeStatusReady && !n.Drain && n.SchedulingEligibility == NodeSchedulingEligible
}

func (n *Node) Canonicalize() {
	if n == nil {
		return
	}

	// COMPAT Remove in 0.10
	// In v0.8.0 we introduced scheduling eligibility, so we need to set it for
	// upgrading nodes
	if n.SchedulingEligibility == "" {
		if n.Drain {
			n.SchedulingEligibility = NodeSchedulingIneligible
		} else {
			n.SchedulingEligibility = NodeSchedulingEligible
		}
	}
}

func (n *Node) Copy() *Node {
	if n == nil {
		return nil
	}
	nn := new(Node)
	*nn = *n
	nn.Attributes = helper.CopyMapStringString(nn.Attributes)
	nn.Resources = nn.Resources.Copy()
	nn.Reserved = nn.Reserved.Copy()
	nn.NodeResources = nn.NodeResources.Copy()
	nn.ReservedResources = nn.ReservedResources.Copy()
	nn.Links = helper.CopyMapStringString(nn.Links)
	nn.Meta = helper.CopyMapStringString(nn.Meta)
	nn.Events = copyNodeEvents(n.Events)
	nn.DrainStrategy = nn.DrainStrategy.Copy()
	nn.Drivers = copyNodeDrivers(n.Drivers)
	return nn
}

// copyNodeEvents is a helper to copy a list of NodeEvent's
func copyNodeEvents(events []*NodeEvent) []*NodeEvent {
	l := len(events)
	if l == 0 {
		return nil
	}

	c := make([]*NodeEvent, l)
	for i, event := range events {
		c[i] = event.Copy()
	}
	return c
}

// copyNodeDrivers is a helper to copy a map of DriverInfo
func copyNodeDrivers(drivers map[string]*DriverInfo) map[string]*DriverInfo {
	l := len(drivers)
	if l == 0 {
		return nil
	}

	c := make(map[string]*DriverInfo, l)
	for driver, info := range drivers {
		c[driver] = info.Copy()
	}
	return c
}

// TerminalStatus returns if the current status is terminal and
// will no longer transition.
func (n *Node) TerminalStatus() bool {
	switch n.Status {
	case NodeStatusDown:
		return true
	default:
		return false
	}
}

// COMPAT(0.11): Remove in 0.11
// ComparableReservedResources returns the reserved resouces on the node
// handling upgrade paths. Reserved networks must be handled separately. After
// 0.11 calls to this should be replaced with:
// node.ReservedResources.Comparable()
func (n *Node) ComparableReservedResources() *ComparableResources {
	// See if we can no-op
	if n.Reserved == nil && n.ReservedResources == nil {
		return nil
	}

	// Node already has 0.9+ behavior
	if n.ReservedResources != nil {
		return n.ReservedResources.Comparable()
	}

	// Upgrade path
	return &ComparableResources{
		Flattened: AllocatedTaskResources{
			Cpu: AllocatedCpuResources{
				CpuShares: int64(n.Reserved.CPU),
			},
			Memory: AllocatedMemoryResources{
				MemoryMB: int64(n.Reserved.MemoryMB),
			},
		},
		Shared: AllocatedSharedResources{
			DiskMB: int64(n.Reserved.DiskMB),
		},
	}
}

// COMPAT(0.11): Remove in 0.11
// ComparableResources returns the resouces on the node
// handling upgrade paths. Networking must be handled separately. After 0.11
// calls to this should be replaced with: node.NodeResources.Comparable()
func (n *Node) ComparableResources() *ComparableResources {
	// Node already has 0.9+ behavior
	if n.NodeResources != nil {
		return n.NodeResources.Comparable()
	}

	// Upgrade path
	return &ComparableResources{
		Flattened: AllocatedTaskResources{
			Cpu: AllocatedCpuResources{
				CpuShares: int64(n.Resources.CPU),
			},
			Memory: AllocatedMemoryResources{
				MemoryMB: int64(n.Resources.MemoryMB),
			},
		},
		Shared: AllocatedSharedResources{
			DiskMB: int64(n.Resources.DiskMB),
		},
	}
}

// Stub returns a summarized version of the node
func (n *Node) Stub() *NodeListStub {

	addr, _, _ := net.SplitHostPort(n.HTTPAddr)

	return &NodeListStub{
		Address:               addr,
		ID:                    n.ID,
		Datacenter:            n.Datacenter,
		Name:                  n.Name,
		NodeClass:             n.NodeClass,
		Version:               n.Attributes["nomad.version"],
		Drain:                 n.Drain,
		SchedulingEligibility: n.SchedulingEligibility,
		Status:                n.Status,
		StatusDescription:     n.StatusDescription,
		Drivers:               n.Drivers,
		CreateIndex:           n.CreateIndex,
		ModifyIndex:           n.ModifyIndex,
	}
}

// NodeListStub is used to return a subset of job information
// for the job list
type NodeListStub struct {
	Address               string
	ID                    string
	Datacenter            string
	Name                  string
	NodeClass             string
	Version               string
	Drain                 bool
	SchedulingEligibility string
	Status                string
	StatusDescription     string
	Drivers               map[string]*DriverInfo
	CreateIndex           uint64
	ModifyIndex           uint64
}

// Resources is used to define the resources available
// on a client
type Resources struct {
	CPU      int
	MemoryMB int
	DiskMB   int
	IOPS     int // COMPAT(0.10): Only being used to issue warnings
	Networks Networks
	Devices  []*RequestedDevice
}

const (
	BytesInMegabyte = 1024 * 1024
)

// DefaultResources is a small resources object that contains the
// default resources requests that we will provide to an object.
// ---  THIS FUNCTION IS REPLICATED IN api/resources.go and should
// be kept in sync.
func DefaultResources() *Resources {
	return &Resources{
		CPU:      100,
		MemoryMB: 300,
	}
}

// MinResources is a small resources object that contains the
// absolute minimum resources that we will provide to an object.
// This should not be confused with the defaults which are
// provided in Canonicalize() ---  THIS FUNCTION IS REPLICATED IN
// api/resources.go and should be kept in sync.
func MinResources() *Resources {
	return &Resources{
		CPU:      20,
		MemoryMB: 10,
	}
}

// DiskInBytes returns the amount of disk resources in bytes.
func (r *Resources) DiskInBytes() int64 {
	return int64(r.DiskMB * BytesInMegabyte)
}

func (r *Resources) Validate() error {
	var mErr multierror.Error
	if err := r.MeetsMinResources(); err != nil {
		mErr.Errors = append(mErr.Errors, err)
	}

	// Ensure the task isn't asking for disk resources
	if r.DiskMB > 0 {
		mErr.Errors = append(mErr.Errors, errors.New("Task can't ask for disk resources, they have to be specified at the task group level."))
	}

	for i, d := range r.Devices {
		if err := d.Validate(); err != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("device %d failed validation: %v", i+1, err))
		}
	}

	return mErr.ErrorOrNil()
}

// Merge merges this resource with another resource.
func (r *Resources) Merge(other *Resources) {
	if other.CPU != 0 {
		r.CPU = other.CPU
	}
	if other.MemoryMB != 0 {
		r.MemoryMB = other.MemoryMB
	}
	if other.DiskMB != 0 {
		r.DiskMB = other.DiskMB
	}
	if len(other.Networks) != 0 {
		r.Networks = other.Networks
	}
	if len(other.Devices) != 0 {
		r.Devices = other.Devices
	}
}

func (r *Resources) Canonicalize() {
	// Ensure that an empty and nil slices are treated the same to avoid scheduling
	// problems since we use reflect DeepEquals.
	if len(r.Networks) == 0 {
		r.Networks = nil
	}
	if len(r.Devices) == 0 {
		r.Devices = nil
	}

	for _, n := range r.Networks {
		n.Canonicalize()
	}
}

// MeetsMinResources returns an error if the resources specified are less than
// the minimum allowed.
// This is based on the minimums defined in the Resources type
func (r *Resources) MeetsMinResources() error {
	var mErr multierror.Error
	minResources := MinResources()
	if r.CPU < minResources.CPU {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("minimum CPU value is %d; got %d", minResources.CPU, r.CPU))
	}
	if r.MemoryMB < minResources.MemoryMB {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("minimum MemoryMB value is %d; got %d", minResources.MemoryMB, r.MemoryMB))
	}
	for i, n := range r.Networks {
		if err := n.MeetsMinResources(); err != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("network resource at index %d failed: %v", i, err))
		}
	}

	return mErr.ErrorOrNil()
}

// Copy returns a deep copy of the resources
func (r *Resources) Copy() *Resources {
	if r == nil {
		return nil
	}
	newR := new(Resources)
	*newR = *r

	// Copy the network objects
	if r.Networks != nil {
		n := len(r.Networks)
		newR.Networks = make([]*NetworkResource, n)
		for i := 0; i < n; i++ {
			newR.Networks[i] = r.Networks[i].Copy()
		}
	}

	// Copy the devices
	if r.Devices != nil {
		n := len(r.Devices)
		newR.Devices = make([]*RequestedDevice, n)
		for i := 0; i < n; i++ {
			newR.Devices[i] = r.Devices[i].Copy()
		}
	}

	return newR
}

// NetIndex finds the matching net index using device name
func (r *Resources) NetIndex(n *NetworkResource) int {
	return r.Networks.NetIndex(n)
}

// Superset checks if one set of resources is a superset
// of another. This ignores network resources, and the NetworkIndex
// should be used for that.
func (r *Resources) Superset(other *Resources) (bool, string) {
	if r.CPU < other.CPU {
		return false, "cpu"
	}
	if r.MemoryMB < other.MemoryMB {
		return false, "memory"
	}
	if r.DiskMB < other.DiskMB {
		return false, "disk"
	}
	return true, ""
}

// Add adds the resources of the delta to this, potentially
// returning an error if not possible.
func (r *Resources) Add(delta *Resources) error {
	if delta == nil {
		return nil
	}
	r.CPU += delta.CPU
	r.MemoryMB += delta.MemoryMB
	r.DiskMB += delta.DiskMB

	for _, n := range delta.Networks {
		// Find the matching interface by IP or CIDR
		idx := r.NetIndex(n)
		if idx == -1 {
			r.Networks = append(r.Networks, n.Copy())
		} else {
			r.Networks[idx].Add(n)
		}
	}
	return nil
}

func (r *Resources) GoString() string {
	return fmt.Sprintf("*%#v", *r)
}

type Port struct {
	Label string
	Value int
}

// NetworkResource is used to represent available network
// resources
type NetworkResource struct {
	Device        string // Name of the device
	CIDR          string // CIDR block of addresses
	IP            string // Host IP address
	MBits         int    // Throughput
	ReservedPorts []Port // Host Reserved ports
	DynamicPorts  []Port // Host Dynamically assigned ports
}

func (nr *NetworkResource) Equals(other *NetworkResource) bool {
	if nr.Device != other.Device {
		return false
	}

	if nr.CIDR != other.CIDR {
		return false
	}

	if nr.IP != other.IP {
		return false
	}

	if nr.MBits != other.MBits {
		return false
	}

	if len(nr.ReservedPorts) != len(other.ReservedPorts) {
		return false
	}

	for i, port := range nr.ReservedPorts {
		if len(other.ReservedPorts) <= i {
			return false
		}
		if port != other.ReservedPorts[i] {
			return false
		}
	}

	if len(nr.DynamicPorts) != len(other.DynamicPorts) {
		return false
	}
	for i, port := range nr.DynamicPorts {
		if len(other.DynamicPorts) <= i {
			return false
		}
		if port != other.DynamicPorts[i] {
			return false
		}
	}
	return true
}

func (n *NetworkResource) Canonicalize() {
	// Ensure that an empty and nil slices are treated the same to avoid scheduling
	// problems since we use reflect DeepEquals.
	if len(n.ReservedPorts) == 0 {
		n.ReservedPorts = nil
	}
	if len(n.DynamicPorts) == 0 {
		n.DynamicPorts = nil
	}
}

// MeetsMinResources returns an error if the resources specified are less than
// the minimum allowed.
func (n *NetworkResource) MeetsMinResources() error {
	var mErr multierror.Error
	if n.MBits < 1 {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("minimum MBits value is 1; got %d", n.MBits))
	}
	return mErr.ErrorOrNil()
}

// Copy returns a deep copy of the network resource
func (n *NetworkResource) Copy() *NetworkResource {
	if n == nil {
		return nil
	}
	newR := new(NetworkResource)
	*newR = *n
	if n.ReservedPorts != nil {
		newR.ReservedPorts = make([]Port, len(n.ReservedPorts))
		copy(newR.ReservedPorts, n.ReservedPorts)
	}
	if n.DynamicPorts != nil {
		newR.DynamicPorts = make([]Port, len(n.DynamicPorts))
		copy(newR.DynamicPorts, n.DynamicPorts)
	}
	return newR
}

// Add adds the resources of the delta to this, potentially
// returning an error if not possible.
func (n *NetworkResource) Add(delta *NetworkResource) {
	if len(delta.ReservedPorts) > 0 {
		n.ReservedPorts = append(n.ReservedPorts, delta.ReservedPorts...)
	}
	n.MBits += delta.MBits
	n.DynamicPorts = append(n.DynamicPorts, delta.DynamicPorts...)
}

func (n *NetworkResource) GoString() string {
	return fmt.Sprintf("*%#v", *n)
}

// PortLabels returns a map of port labels to their assigned host ports.
func (n *NetworkResource) PortLabels() map[string]int {
	num := len(n.ReservedPorts) + len(n.DynamicPorts)
	labelValues := make(map[string]int, num)
	for _, port := range n.ReservedPorts {
		labelValues[port.Label] = port.Value
	}
	for _, port := range n.DynamicPorts {
		labelValues[port.Label] = port.Value
	}
	return labelValues
}

// Networks defined for a task on the Resources struct.
type Networks []*NetworkResource

// Port assignment and IP for the given label or empty values.
func (ns Networks) Port(label string) (string, int) {
	for _, n := range ns {
		for _, p := range n.ReservedPorts {
			if p.Label == label {
				return n.IP, p.Value
			}
		}
		for _, p := range n.DynamicPorts {
			if p.Label == label {
				return n.IP, p.Value
			}
		}
	}
	return "", 0
}

func (ns Networks) NetIndex(n *NetworkResource) int {
	for idx, net := range ns {
		if net.Device == n.Device {
			return idx
		}
	}
	return -1
}

// RequestedDevice is used to request a device for a task.
type RequestedDevice struct {
	// Name is the request name. The possible values are as follows:
	// * <type>: A single value only specifies the type of request.
	// * <vendor>/<type>: A single slash delimiter assumes the vendor and type of device is specified.
	// * <vendor>/<type>/<name>: Two slash delimiters assume vendor, type and specific model are specified.
	//
	// Examples are as follows:
	// * "gpu"
	// * "nvidia/gpu"
	// * "nvidia/gpu/GTX2080Ti"
	Name string

	// Count is the number of requested devices
	Count uint64

	// Constraints are a set of constraints to apply when selecting the device
	// to use.
	Constraints []*Constraint

	// Affinities are a set of affinites to apply when selecting the device
	// to use.
	Affinities []*Affinity
}

func (r *RequestedDevice) Copy() *RequestedDevice {
	if r == nil {
		return nil
	}

	nr := *r
	nr.Constraints = CopySliceConstraints(nr.Constraints)
	nr.Affinities = CopySliceAffinities(nr.Affinities)

	return &nr
}

func (r *RequestedDevice) ID() *DeviceIdTuple {
	if r == nil || r.Name == "" {
		return nil
	}

	parts := strings.SplitN(r.Name, "/", 3)
	switch len(parts) {
	case 1:
		return &DeviceIdTuple{
			Type: parts[0],
		}
	case 2:
		return &DeviceIdTuple{
			Vendor: parts[0],
			Type:   parts[1],
		}
	default:
		return &DeviceIdTuple{
			Vendor: parts[0],
			Type:   parts[1],
			Name:   parts[2],
		}
	}
}

func (r *RequestedDevice) Validate() error {
	if r == nil {
		return nil
	}

	var mErr multierror.Error
	if r.Name == "" {
		multierror.Append(&mErr, errors.New("device name must be given as one of the following: type, vendor/type, or vendor/type/name"))
	}

	for idx, constr := range r.Constraints {
		// Ensure that the constraint doesn't use an operand we do not allow
		switch constr.Operand {
		case ConstraintDistinctHosts, ConstraintDistinctProperty:
			outer := fmt.Errorf("Constraint %d validation failed: using unsupported operand %q", idx+1, constr.Operand)
			multierror.Append(&mErr, outer)
		default:
			if err := constr.Validate(); err != nil {
				outer := fmt.Errorf("Constraint %d validation failed: %s", idx+1, err)
				multierror.Append(&mErr, outer)
			}
		}
	}
	for idx, affinity := range r.Affinities {
		if err := affinity.Validate(); err != nil {
			outer := fmt.Errorf("Affinity %d validation failed: %s", idx+1, err)
			multierror.Append(&mErr, outer)
		}
	}

	return mErr.ErrorOrNil()
}

// NodeResources is used to define the resources available on a client node.
type NodeResources struct {
	Cpu      NodeCpuResources
	Memory   NodeMemoryResources
	Disk     NodeDiskResources
	Networks Networks
	Devices  []*NodeDeviceResource
}

func (n *NodeResources) Copy() *NodeResources {
	if n == nil {
		return nil
	}

	newN := new(NodeResources)
	*newN = *n

	// Copy the networks
	if n.Networks != nil {
		networks := len(n.Networks)
		newN.Networks = make([]*NetworkResource, networks)
		for i := 0; i < networks; i++ {
			newN.Networks[i] = n.Networks[i].Copy()
		}
	}

	// Copy the devices
	if n.Devices != nil {
		devices := len(n.Devices)
		newN.Devices = make([]*NodeDeviceResource, devices)
		for i := 0; i < devices; i++ {
			newN.Devices[i] = n.Devices[i].Copy()
		}
	}

	return newN
}

// Comparable returns a comparable version of the nodes resources. This
// conversion can be lossy so care must be taken when using it.
func (n *NodeResources) Comparable() *ComparableResources {
	if n == nil {
		return nil
	}

	c := &ComparableResources{
		Flattened: AllocatedTaskResources{
			Cpu: AllocatedCpuResources{
				CpuShares: n.Cpu.CpuShares,
			},
			Memory: AllocatedMemoryResources{
				MemoryMB: n.Memory.MemoryMB,
			},
			Networks: n.Networks,
		},
		Shared: AllocatedSharedResources{
			DiskMB: n.Disk.DiskMB,
		},
	}
	return c
}

func (n *NodeResources) Merge(o *NodeResources) {
	if o == nil {
		return
	}

	n.Cpu.Merge(&o.Cpu)
	n.Memory.Merge(&o.Memory)
	n.Disk.Merge(&o.Disk)

	if len(o.Networks) != 0 {
		n.Networks = o.Networks
	}

	if len(o.Devices) != 0 {
		n.Devices = o.Devices
	}
}

func (n *NodeResources) Equals(o *NodeResources) bool {
	if o == nil && n == nil {
		return true
	} else if o == nil {
		return false
	} else if n == nil {
		return false
	}

	if !n.Cpu.Equals(&o.Cpu) {
		return false
	}
	if !n.Memory.Equals(&o.Memory) {
		return false
	}
	if !n.Disk.Equals(&o.Disk) {
		return false
	}

	if len(n.Networks) != len(o.Networks) {
		return false
	}
	for i, n := range n.Networks {
		if !n.Equals(o.Networks[i]) {
			return false
		}
	}

	// Check the devices
	if !DevicesEquals(n.Devices, o.Devices) {
		return false
	}

	return true
}

// DevicesEquals returns true if the two device arrays are equal
func DevicesEquals(d1, d2 []*NodeDeviceResource) bool {
	if len(d1) != len(d2) {
		return false
	}
	idMap := make(map[DeviceIdTuple]*NodeDeviceResource, len(d1))
	for _, d := range d1 {
		idMap[*d.ID()] = d
	}
	for _, otherD := range d2 {
		if d, ok := idMap[*otherD.ID()]; !ok || !d.Equals(otherD) {
			return false
		}
	}

	return true
}

// NodeCpuResources captures the CPU resources of the node.
type NodeCpuResources struct {
	// CpuShares is the CPU shares available. This is calculated by number of
	// cores multiplied by the core frequency.
	CpuShares int64
}

func (n *NodeCpuResources) Merge(o *NodeCpuResources) {
	if o == nil {
		return
	}

	if o.CpuShares != 0 {
		n.CpuShares = o.CpuShares
	}
}

func (n *NodeCpuResources) Equals(o *NodeCpuResources) bool {
	if o == nil && n == nil {
		return true
	} else if o == nil {
		return false
	} else if n == nil {
		return false
	}

	if n.CpuShares != o.CpuShares {
		return false
	}

	return true
}

// NodeMemoryResources captures the memory resources of the node
type NodeMemoryResources struct {
	// MemoryMB is the total available memory on the node
	MemoryMB int64
}

func (n *NodeMemoryResources) Merge(o *NodeMemoryResources) {
	if o == nil {
		return
	}

	if o.MemoryMB != 0 {
		n.MemoryMB = o.MemoryMB
	}
}

func (n *NodeMemoryResources) Equals(o *NodeMemoryResources) bool {
	if o == nil && n == nil {
		return true
	} else if o == nil {
		return false
	} else if n == nil {
		return false
	}

	if n.MemoryMB != o.MemoryMB {
		return false
	}

	return true
}

// NodeDiskResources captures the disk resources of the node
type NodeDiskResources struct {
	// DiskMB is the total available disk space on the node
	DiskMB int64
}

func (n *NodeDiskResources) Merge(o *NodeDiskResources) {
	if o == nil {
		return
	}
	if o.DiskMB != 0 {
		n.DiskMB = o.DiskMB
	}
}

func (n *NodeDiskResources) Equals(o *NodeDiskResources) bool {
	if o == nil && n == nil {
		return true
	} else if o == nil {
		return false
	} else if n == nil {
		return false
	}

	if n.DiskMB != o.DiskMB {
		return false
	}

	return true
}

// DeviceIdTuple is the tuple that identifies a device
type DeviceIdTuple struct {
	Vendor string
	Type   string
	Name   string
}

func (d *DeviceIdTuple) String() string {
	if d == nil {
		return ""
	}

	return fmt.Sprintf("%s/%s/%s", d.Vendor, d.Type, d.Name)
}

// Matches returns if this Device ID is a superset of the passed ID.
func (id *DeviceIdTuple) Matches(other *DeviceIdTuple) bool {
	if other == nil {
		return false
	}

	if other.Name != "" && other.Name != id.Name {
		return false
	}

	if other.Vendor != "" && other.Vendor != id.Vendor {
		return false
	}

	if other.Type != "" && other.Type != id.Type {
		return false
	}

	return true
}

// Equals returns if this Device ID is the same as the passed ID.
func (id *DeviceIdTuple) Equals(o *DeviceIdTuple) bool {
	if id == nil && o == nil {
		return true
	} else if id == nil || o == nil {
		return false
	}

	return o.Vendor == id.Vendor && o.Type == id.Type && o.Name == id.Name
}

// NodeDeviceResource captures a set of devices sharing a common
// vendor/type/device_name tuple.
type NodeDeviceResource struct {
	Vendor     string
	Type       string
	Name       string
	Instances  []*NodeDevice
	Attributes map[string]*psstructs.Attribute
}

func (n *NodeDeviceResource) ID() *DeviceIdTuple {
	if n == nil {
		return nil
	}

	return &DeviceIdTuple{
		Vendor: n.Vendor,
		Type:   n.Type,
		Name:   n.Name,
	}
}

func (n *NodeDeviceResource) Copy() *NodeDeviceResource {
	if n == nil {
		return nil
	}

	// Copy the primitives
	nn := *n

	// Copy the device instances
	if l := len(nn.Instances); l != 0 {
		nn.Instances = make([]*NodeDevice, 0, l)
		for _, d := range n.Instances {
			nn.Instances = append(nn.Instances, d.Copy())
		}
	}

	// Copy the Attributes
	nn.Attributes = psstructs.CopyMapStringAttribute(nn.Attributes)

	return &nn
}

func (n *NodeDeviceResource) Equals(o *NodeDeviceResource) bool {
	if o == nil && n == nil {
		return true
	} else if o == nil {
		return false
	} else if n == nil {
		return false
	}

	if n.Vendor != o.Vendor {
		return false
	} else if n.Type != o.Type {
		return false
	} else if n.Name != o.Name {
		return false
	}

	// Check the attributes
	if len(n.Attributes) != len(o.Attributes) {
		return false
	}
	for k, v := range n.Attributes {
		if otherV, ok := o.Attributes[k]; !ok || v != otherV {
			return false
		}
	}

	// Check the instances
	if len(n.Instances) != len(o.Instances) {
		return false
	}
	idMap := make(map[string]*NodeDevice, len(n.Instances))
	for _, d := range n.Instances {
		idMap[d.ID] = d
	}
	for _, otherD := range o.Instances {
		if d, ok := idMap[otherD.ID]; !ok || !d.Equals(otherD) {
			return false
		}
	}

	return true
}

// NodeDevice is an instance of a particular device.
type NodeDevice struct {
	// ID is the ID of the device.
	ID string

	// Healthy captures whether the device is healthy.
	Healthy bool

	// HealthDescription is used to provide a human readable description of why
	// the device may be unhealthy.
	HealthDescription string

	// Locality stores HW locality information for the node to optionally be
	// used when making placement decisions.
	Locality *NodeDeviceLocality
}

func (n *NodeDevice) Equals(o *NodeDevice) bool {
	if o == nil && n == nil {
		return true
	} else if o == nil {
		return false
	} else if n == nil {
		return false
	}

	if n.ID != o.ID {
		return false
	} else if n.Healthy != o.Healthy {
		return false
	} else if n.HealthDescription != o.HealthDescription {
		return false
	} else if !n.Locality.Equals(o.Locality) {
		return false
	}

	return false
}

func (n *NodeDevice) Copy() *NodeDevice {
	if n == nil {
		return nil
	}

	// Copy the primitives
	nn := *n

	// Copy the locality
	nn.Locality = nn.Locality.Copy()

	return &nn
}

// NodeDeviceLocality stores information about the devices hardware locality on
// the node.
type NodeDeviceLocality struct {
	// PciBusID is the PCI Bus ID for the device.
	PciBusID string
}

func (n *NodeDeviceLocality) Equals(o *NodeDeviceLocality) bool {
	if o == nil && n == nil {
		return true
	} else if o == nil {
		return false
	} else if n == nil {
		return false
	}

	if n.PciBusID != o.PciBusID {
		return false
	}

	return true
}

func (n *NodeDeviceLocality) Copy() *NodeDeviceLocality {
	if n == nil {
		return nil
	}

	// Copy the primitives
	nn := *n
	return &nn
}

// NodeReservedResources is used to capture the resources on a client node that
// should be reserved and not made available to jobs.
type NodeReservedResources struct {
	Cpu      NodeReservedCpuResources
	Memory   NodeReservedMemoryResources
	Disk     NodeReservedDiskResources
	Networks NodeReservedNetworkResources
}

func (n *NodeReservedResources) Copy() *NodeReservedResources {
	if n == nil {
		return nil
	}
	newN := new(NodeReservedResources)
	*newN = *n
	return newN
}

// Comparable returns a comparable version of the node's reserved resources. The
// returned resources doesn't contain any network information. This conversion
// can be lossy so care must be taken when using it.
func (n *NodeReservedResources) Comparable() *ComparableResources {
	if n == nil {
		return nil
	}

	c := &ComparableResources{
		Flattened: AllocatedTaskResources{
			Cpu: AllocatedCpuResources{
				CpuShares: n.Cpu.CpuShares,
			},
			Memory: AllocatedMemoryResources{
				MemoryMB: n.Memory.MemoryMB,
			},
		},
		Shared: AllocatedSharedResources{
			DiskMB: n.Disk.DiskMB,
		},
	}
	return c
}

// NodeReservedCpuResources captures the reserved CPU resources of the node.
type NodeReservedCpuResources struct {
	CpuShares int64
}

// NodeReservedMemoryResources captures the reserved memory resources of the node.
type NodeReservedMemoryResources struct {
	MemoryMB int64
}

// NodeReservedDiskResources captures the reserved disk resources of the node.
type NodeReservedDiskResources struct {
	DiskMB int64
}

// NodeReservedNetworkResources captures the reserved network resources of the node.
type NodeReservedNetworkResources struct {
	// ReservedHostPorts is the set of ports reserved on all host network
	// interfaces. Its format is a comma separate list of integers or integer
	// ranges. (80,443,1000-2000,2005)
	ReservedHostPorts string
}

// ParsePortHostPorts returns the reserved host ports.
func (n *NodeReservedNetworkResources) ParseReservedHostPorts() ([]uint64, error) {
	return ParsePortRanges(n.ReservedHostPorts)
}

// AllocatedResources is the set of resources to be used by an allocation.
type AllocatedResources struct {
	// Tasks is a mapping of task name to the resources for the task.
	Tasks map[string]*AllocatedTaskResources

	// Shared is the set of resource that are shared by all tasks in the group.
	Shared AllocatedSharedResources
}

func (a *AllocatedResources) Copy() *AllocatedResources {
	if a == nil {
		return nil
	}
	newA := new(AllocatedResources)
	*newA = *a

	if a.Tasks != nil {
		tr := make(map[string]*AllocatedTaskResources, len(newA.Tasks))
		for task, resource := range newA.Tasks {
			tr[task] = resource.Copy()
		}
		newA.Tasks = tr
	}

	return newA
}

// Comparable returns a comparable version of the allocations allocated
// resources. This conversion can be lossy so care must be taken when using it.
func (a *AllocatedResources) Comparable() *ComparableResources {
	if a == nil {
		return nil
	}

	c := &ComparableResources{
		Shared: a.Shared,
	}
	for _, r := range a.Tasks {
		c.Flattened.Add(r)
	}
	return c
}

// OldTaskResources returns the pre-0.9.0 map of task resources
func (a *AllocatedResources) OldTaskResources() map[string]*Resources {
	m := make(map[string]*Resources, len(a.Tasks))
	for name, res := range a.Tasks {
		m[name] = &Resources{
			CPU:      int(res.Cpu.CpuShares),
			MemoryMB: int(res.Memory.MemoryMB),
			Networks: res.Networks,
		}
	}

	return m
}

// AllocatedTaskResources are the set of resources allocated to a task.
type AllocatedTaskResources struct {
	Cpu      AllocatedCpuResources
	Memory   AllocatedMemoryResources
	Networks Networks
	Devices  []*AllocatedDeviceResource
}

func (a *AllocatedTaskResources) Copy() *AllocatedTaskResources {
	if a == nil {
		return nil
	}
	newA := new(AllocatedTaskResources)
	*newA = *a

	// Copy the networks
	if a.Networks != nil {
		n := len(a.Networks)
		newA.Networks = make([]*NetworkResource, n)
		for i := 0; i < n; i++ {
			newA.Networks[i] = a.Networks[i].Copy()
		}
	}

	// Copy the devices
	if newA.Devices != nil {
		n := len(a.Devices)
		newA.Devices = make([]*AllocatedDeviceResource, n)
		for i := 0; i < n; i++ {
			newA.Devices[i] = a.Devices[i].Copy()
		}
	}

	return newA
}

// NetIndex finds the matching net index using device name
func (a *AllocatedTaskResources) NetIndex(n *NetworkResource) int {
	return a.Networks.NetIndex(n)
}

func (a *AllocatedTaskResources) Add(delta *AllocatedTaskResources) {
	if delta == nil {
		return
	}

	a.Cpu.Add(&delta.Cpu)
	a.Memory.Add(&delta.Memory)

	for _, n := range delta.Networks {
		// Find the matching interface by IP or CIDR
		idx := a.NetIndex(n)
		if idx == -1 {
			a.Networks = append(a.Networks, n.Copy())
		} else {
			a.Networks[idx].Add(n)
		}
	}

	for _, d := range delta.Devices {
		// Find the matching device
		idx := AllocatedDevices(a.Devices).Index(d)
		if idx == -1 {
			a.Devices = append(a.Devices, d.Copy())
		} else {
			a.Devices[idx].Add(d)
		}
	}
}

// Comparable turns AllocatedTaskResources into ComparableResources
// as a helper step in preemption
func (a *AllocatedTaskResources) Comparable() *ComparableResources {
	ret := &ComparableResources{
		Flattened: AllocatedTaskResources{
			Cpu: AllocatedCpuResources{
				CpuShares: a.Cpu.CpuShares,
			},
			Memory: AllocatedMemoryResources{
				MemoryMB: a.Memory.MemoryMB,
			},
		},
	}
	if len(a.Networks) > 0 {
		for _, net := range a.Networks {
			ret.Flattened.Networks = append(ret.Flattened.Networks, net)
		}
	}
	return ret
}

// Subtract only subtracts CPU and Memory resources. Network utilization
// is managed separately in NetworkIndex
func (a *AllocatedTaskResources) Subtract(delta *AllocatedTaskResources) {
	if delta == nil {
		return
	}

	a.Cpu.Subtract(&delta.Cpu)
	a.Memory.Subtract(&delta.Memory)
}

// AllocatedSharedResources are the set of resources allocated to a task group.
type AllocatedSharedResources struct {
	DiskMB int64
}

func (a *AllocatedSharedResources) Add(delta *AllocatedSharedResources) {
	if delta == nil {
		return
	}

	a.DiskMB += delta.DiskMB
}

func (a *AllocatedSharedResources) Subtract(delta *AllocatedSharedResources) {
	if delta == nil {
		return
	}

	a.DiskMB -= delta.DiskMB
}

// AllocatedCpuResources captures the allocated CPU resources.
type AllocatedCpuResources struct {
	CpuShares int64
}

func (a *AllocatedCpuResources) Add(delta *AllocatedCpuResources) {
	if delta == nil {
		return
	}

	a.CpuShares += delta.CpuShares
}

func (a *AllocatedCpuResources) Subtract(delta *AllocatedCpuResources) {
	if delta == nil {
		return
	}

	a.CpuShares -= delta.CpuShares
}

// AllocatedMemoryResources captures the allocated memory resources.
type AllocatedMemoryResources struct {
	MemoryMB int64
}

func (a *AllocatedMemoryResources) Add(delta *AllocatedMemoryResources) {
	if delta == nil {
		return
	}

	a.MemoryMB += delta.MemoryMB
}

func (a *AllocatedMemoryResources) Subtract(delta *AllocatedMemoryResources) {
	if delta == nil {
		return
	}

	a.MemoryMB -= delta.MemoryMB
}

type AllocatedDevices []*AllocatedDeviceResource

// Index finds the matching index using the passed device. If not found, -1 is
// returned.
func (a AllocatedDevices) Index(d *AllocatedDeviceResource) int {
	if d == nil {
		return -1
	}

	for i, o := range a {
		if o.ID().Equals(d.ID()) {
			return i
		}
	}

	return -1
}

// AllocatedDeviceResource captures a set of allocated devices.
type AllocatedDeviceResource struct {
	// Vendor, Type, and Name are used to select the plugin to request the
	// device IDs from.
	Vendor string
	Type   string
	Name   string

	// DeviceIDs is the set of allocated devices
	DeviceIDs []string
}

func (a *AllocatedDeviceResource) ID() *DeviceIdTuple {
	if a == nil {
		return nil
	}

	return &DeviceIdTuple{
		Vendor: a.Vendor,
		Type:   a.Type,
		Name:   a.Name,
	}
}

func (a *AllocatedDeviceResource) Add(delta *AllocatedDeviceResource) {
	if delta == nil {
		return
	}

	a.DeviceIDs = append(a.DeviceIDs, delta.DeviceIDs...)
}

func (a *AllocatedDeviceResource) Copy() *AllocatedDeviceResource {
	if a == nil {
		return a
	}

	na := *a

	// Copy the devices
	na.DeviceIDs = make([]string, len(a.DeviceIDs))
	for i, id := range a.DeviceIDs {
		na.DeviceIDs[i] = id
	}

	return &na
}

// ComparableResources is the set of resources allocated to a task group but
// not keyed by Task, making it easier to compare.
type ComparableResources struct {
	Flattened AllocatedTaskResources
	Shared    AllocatedSharedResources
}

func (c *ComparableResources) Add(delta *ComparableResources) {
	if delta == nil {
		return
	}

	c.Flattened.Add(&delta.Flattened)
	c.Shared.Add(&delta.Shared)
}

func (c *ComparableResources) Subtract(delta *ComparableResources) {
	if delta == nil {
		return
	}

	c.Flattened.Subtract(&delta.Flattened)
	c.Shared.Subtract(&delta.Shared)
}

func (c *ComparableResources) Copy() *ComparableResources {
	if c == nil {
		return nil
	}
	newR := new(ComparableResources)
	*newR = *c
	return newR
}

// Superset checks if one set of resources is a superset of another. This
// ignores network resources, and the NetworkIndex should be used for that.
func (c *ComparableResources) Superset(other *ComparableResources) (bool, string) {
	if c.Flattened.Cpu.CpuShares < other.Flattened.Cpu.CpuShares {
		return false, "cpu"
	}
	if c.Flattened.Memory.MemoryMB < other.Flattened.Memory.MemoryMB {
		return false, "memory"
	}
	if c.Shared.DiskMB < other.Shared.DiskMB {
		return false, "disk"
	}
	return true, ""
}

// allocated finds the matching net index using device name
func (c *ComparableResources) NetIndex(n *NetworkResource) int {
	return c.Flattened.Networks.NetIndex(n)
}

const (
	// JobTypeNomad is reserved for internal system tasks and is
	// always handled by the CoreScheduler.
	JobTypeCore    = "_core"
	JobTypeService = "service"
	JobTypeBatch   = "batch"
	JobTypeSystem  = "system"
)

const (
	JobStatusPending = "pending" // Pending means the job is waiting on scheduling
	JobStatusRunning = "running" // Running means the job has non-terminal allocations
	JobStatusDead    = "dead"    // Dead means all evaluation's and allocations are terminal
)

const (
	// JobMinPriority is the minimum allowed priority
	JobMinPriority = 1

	// JobDefaultPriority is the default priority if not
	// not specified.
	JobDefaultPriority = 50

	// JobMaxPriority is the maximum allowed priority
	JobMaxPriority = 100

	// Ensure CoreJobPriority is higher than any user
	// specified job so that it gets priority. This is important
	// for the system to remain healthy.
	CoreJobPriority = JobMaxPriority * 2

	// JobTrackedVersions is the number of historic job versions that are
	// kept.
	JobTrackedVersions = 6
)

// Job is the scope of a scheduling request to Nomad. It is the largest
// scoped object, and is a named collection of task groups. Each task group
// is further composed of tasks. A task group (TG) is the unit of scheduling
// however.
type Job struct {
	// Stop marks whether the user has stopped the job. A stopped job will
	// have all created allocations stopped and acts as a way to stop a job
	// without purging it from the system. This allows existing allocs to be
	// queried and the job to be inspected as it is being killed.
	Stop bool

	// Region is the Nomad region that handles scheduling this job
	Region string

	// Namespace is the namespace the job is submitted into.
	Namespace string

	// ID is a unique identifier for the job per region. It can be
	// specified hierarchically like LineOfBiz/OrgName/Team/Project
	ID string

	// ParentID is the unique identifier of the job that spawned this job.
	ParentID string

	// Name is the logical name of the job used to refer to it. This is unique
	// per region, but not unique globally.
	Name string

	// Type is used to control various behaviors about the job. Most jobs
	// are service jobs, meaning they are expected to be long lived.
	// Some jobs are batch oriented meaning they run and then terminate.
	// This can be extended in the future to support custom schedulers.
	Type string

	// Priority is used to control scheduling importance and if this job
	// can preempt other jobs.
	Priority int

	// AllAtOnce is used to control if incremental scheduling of task groups
	// is allowed or if we must do a gang scheduling of the entire job. This
	// can slow down larger jobs if resources are not available.
	AllAtOnce bool

	// Datacenters contains all the datacenters this job is allowed to span
	Datacenters []string

	// Constraints can be specified at a job level and apply to
	// all the task groups and tasks.
	Constraints []*Constraint

	// Affinities can be specified at the job level to express
	// scheduling preferences that apply to all groups and tasks
	Affinities []*Affinity

	// Spread can be specified at the job level to express spreading
	// allocations across a desired attribute, such as datacenter
	Spreads []*Spread

	// TaskGroups are the collections of task groups that this job needs
	// to run. Each task group is an atomic unit of scheduling and placement.
	TaskGroups []*TaskGroup

	// COMPAT: Remove in 0.7.0. Stagger is deprecated in 0.6.0.
	Update UpdateStrategy

	// Periodic is used to define the interval the job is run at.
	Periodic *PeriodicConfig

	// ParameterizedJob is used to specify the job as a parameterized job
	// for dispatching.
	ParameterizedJob *ParameterizedJobConfig

	// Dispatched is used to identify if the Job has been dispatched from a
	// parameterized job.
	Dispatched bool

	// Payload is the payload supplied when the job was dispatched.
	Payload []byte

	// Meta is used to associate arbitrary metadata with this
	// job. This is opaque to Nomad.
	Meta map[string]string

	// VaultToken is the Vault token that proves the submitter of the job has
	// access to the specified Vault policies. This field is only used to
	// transfer the token and is not stored after Job submission.
	VaultToken string

	// Job status
	Status string

	// StatusDescription is meant to provide more human useful information
	StatusDescription string

	// Stable marks a job as stable. Stability is only defined on "service" and
	// "system" jobs. The stability of a job will be set automatically as part
	// of a deployment and can be manually set via APIs.
	Stable bool

	// Version is a monotonically increasing version number that is incremented
	// on each job register.
	Version uint64

	// SubmitTime is the time at which the job was submitted as a UnixNano in
	// UTC
	SubmitTime int64

	// Raft Indexes
	CreateIndex    uint64
	ModifyIndex    uint64
	JobModifyIndex uint64
}

// NamespacedID returns the namespaced id useful for logging
func (j *Job) NamespacedID() *NamespacedID {
	return &NamespacedID{
		ID:        j.ID,
		Namespace: j.Namespace,
	}
}

// Canonicalize is used to canonicalize fields in the Job. This should be called
// when registering a Job. A set of warnings are returned if the job was changed
// in anyway that the user should be made aware of.
func (j *Job) Canonicalize() (warnings error) {
	if j == nil {
		return nil
	}

	var mErr multierror.Error
	// Ensure that an empty and nil map are treated the same to avoid scheduling
	// problems since we use reflect DeepEquals.
	if len(j.Meta) == 0 {
		j.Meta = nil
	}

	// Ensure the job is in a namespace.
	if j.Namespace == "" {
		j.Namespace = DefaultNamespace
	}

	for _, tg := range j.TaskGroups {
		tg.Canonicalize(j)
	}

	if j.ParameterizedJob != nil {
		j.ParameterizedJob.Canonicalize()
	}

	if j.Periodic != nil {
		j.Periodic.Canonicalize()
	}

	return mErr.ErrorOrNil()
}

// Copy returns a deep copy of the Job. It is expected that callers use recover.
// This job can panic if the deep copy failed as it uses reflection.
func (j *Job) Copy() *Job {
	if j == nil {
		return nil
	}
	nj := new(Job)
	*nj = *j
	nj.Datacenters = helper.CopySliceString(nj.Datacenters)
	nj.Constraints = CopySliceConstraints(nj.Constraints)
	nj.Affinities = CopySliceAffinities(nj.Affinities)

	if j.TaskGroups != nil {
		tgs := make([]*TaskGroup, len(nj.TaskGroups))
		for i, tg := range nj.TaskGroups {
			tgs[i] = tg.Copy()
		}
		nj.TaskGroups = tgs
	}

	nj.Periodic = nj.Periodic.Copy()
	nj.Meta = helper.CopyMapStringString(nj.Meta)
	nj.ParameterizedJob = nj.ParameterizedJob.Copy()
	return nj
}

// Validate is used to sanity check a job input
func (j *Job) Validate() error {
	var mErr multierror.Error

	if j.Region == "" {
		mErr.Errors = append(mErr.Errors, errors.New("Missing job region"))
	}
	if j.ID == "" {
		mErr.Errors = append(mErr.Errors, errors.New("Missing job ID"))
	} else if strings.Contains(j.ID, " ") {
		mErr.Errors = append(mErr.Errors, errors.New("Job ID contains a space"))
	}
	if j.Name == "" {
		mErr.Errors = append(mErr.Errors, errors.New("Missing job name"))
	}
	if j.Namespace == "" {
		mErr.Errors = append(mErr.Errors, errors.New("Job must be in a namespace"))
	}
	switch j.Type {
	case JobTypeCore, JobTypeService, JobTypeBatch, JobTypeSystem:
	case "":
		mErr.Errors = append(mErr.Errors, errors.New("Missing job type"))
	default:
		mErr.Errors = append(mErr.Errors, fmt.Errorf("Invalid job type: %q", j.Type))
	}
	if j.Priority < JobMinPriority || j.Priority > JobMaxPriority {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("Job priority must be between [%d, %d]", JobMinPriority, JobMaxPriority))
	}
	if len(j.Datacenters) == 0 {
		mErr.Errors = append(mErr.Errors, errors.New("Missing job datacenters"))
	}
	if len(j.TaskGroups) == 0 {
		mErr.Errors = append(mErr.Errors, errors.New("Missing job task groups"))
	}
	for idx, constr := range j.Constraints {
		if err := constr.Validate(); err != nil {
			outer := fmt.Errorf("Constraint %d validation failed: %s", idx+1, err)
			mErr.Errors = append(mErr.Errors, outer)
		}
	}
	if j.Type == JobTypeSystem {
		if j.Affinities != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("System jobs may not have an affinity stanza"))
		}
	} else {
		for idx, affinity := range j.Affinities {
			if err := affinity.Validate(); err != nil {
				outer := fmt.Errorf("Affinity %d validation failed: %s", idx+1, err)
				mErr.Errors = append(mErr.Errors, outer)
			}
		}
	}

	if j.Type == JobTypeSystem {
		if j.Spreads != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("System jobs may not have a spread stanza"))
		}
	} else {
		for idx, spread := range j.Spreads {
			if err := spread.Validate(); err != nil {
				outer := fmt.Errorf("Spread %d validation failed: %s", idx+1, err)
				mErr.Errors = append(mErr.Errors, outer)
			}
		}
	}

	// Check for duplicate task groups
	taskGroups := make(map[string]int)
	for idx, tg := range j.TaskGroups {
		if tg.Name == "" {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Job task group %d missing name", idx+1))
		} else if existing, ok := taskGroups[tg.Name]; ok {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Job task group %d redefines '%s' from group %d", idx+1, tg.Name, existing+1))
		} else {
			taskGroups[tg.Name] = idx
		}

		if j.Type == "system" && tg.Count > 1 {
			mErr.Errors = append(mErr.Errors,
				fmt.Errorf("Job task group %s has count %d. Count cannot exceed 1 with system scheduler",
					tg.Name, tg.Count))
		}
	}

	// Validate the task group
	for _, tg := range j.TaskGroups {
		if err := tg.Validate(j); err != nil {
			outer := fmt.Errorf("Task group %s validation failed: %v", tg.Name, err)
			mErr.Errors = append(mErr.Errors, outer)
		}
	}

	// Validate periodic is only used with batch jobs.
	if j.IsPeriodic() && j.Periodic.Enabled {
		if j.Type != JobTypeBatch {
			mErr.Errors = append(mErr.Errors,
				fmt.Errorf("Periodic can only be used with %q scheduler", JobTypeBatch))
		}

		if err := j.Periodic.Validate(); err != nil {
			mErr.Errors = append(mErr.Errors, err)
		}
	}

	if j.IsParameterized() {
		if j.Type != JobTypeBatch {
			mErr.Errors = append(mErr.Errors,
				fmt.Errorf("Parameterized job can only be used with %q scheduler", JobTypeBatch))
		}

		if err := j.ParameterizedJob.Validate(); err != nil {
			mErr.Errors = append(mErr.Errors, err)
		}
	}

	return mErr.ErrorOrNil()
}

// Warnings returns a list of warnings that may be from dubious settings or
// deprecation warnings.
func (j *Job) Warnings() error {
	var mErr multierror.Error

	// Check the groups
	for _, tg := range j.TaskGroups {
		if err := tg.Warnings(j); err != nil {
			outer := fmt.Errorf("Group %q has warnings: %v", tg.Name, err)
			mErr.Errors = append(mErr.Errors, outer)
		}
	}

	return mErr.ErrorOrNil()
}

// LookupTaskGroup finds a task group by name
func (j *Job) LookupTaskGroup(name string) *TaskGroup {
	for _, tg := range j.TaskGroups {
		if tg.Name == name {
			return tg
		}
	}
	return nil
}

// CombinedTaskMeta takes a TaskGroup and Task name and returns the combined
// meta data for the task. When joining Job, Group and Task Meta, the precedence
// is by deepest scope (Task > Group > Job).
func (j *Job) CombinedTaskMeta(groupName, taskName string) map[string]string {
	group := j.LookupTaskGroup(groupName)
	if group == nil {
		return nil
	}

	task := group.LookupTask(taskName)
	if task == nil {
		return nil
	}

	meta := helper.CopyMapStringString(task.Meta)
	if meta == nil {
		meta = make(map[string]string, len(group.Meta)+len(j.Meta))
	}

	// Add the group specific meta
	for k, v := range group.Meta {
		if _, ok := meta[k]; !ok {
			meta[k] = v
		}
	}

	// Add the job specific meta
	for k, v := range j.Meta {
		if _, ok := meta[k]; !ok {
			meta[k] = v
		}
	}

	return meta
}

// Stopped returns if a job is stopped.
func (j *Job) Stopped() bool {
	return j == nil || j.Stop
}

// HasUpdateStrategy returns if any task group in the job has an update strategy
func (j *Job) HasUpdateStrategy() bool {
	for _, tg := range j.TaskGroups {
		if tg.Update != nil {
			return true
		}
	}

	return false
}

// Stub is used to return a summary of the job
func (j *Job) Stub(summary *JobSummary) *JobListStub {
	return &JobListStub{
		ID:                j.ID,
		ParentID:          j.ParentID,
		Name:              j.Name,
		Datacenters:       j.Datacenters,
		Type:              j.Type,
		Priority:          j.Priority,
		Periodic:          j.IsPeriodic(),
		ParameterizedJob:  j.IsParameterized(),
		Stop:              j.Stop,
		Status:            j.Status,
		StatusDescription: j.StatusDescription,
		CreateIndex:       j.CreateIndex,
		ModifyIndex:       j.ModifyIndex,
		JobModifyIndex:    j.JobModifyIndex,
		SubmitTime:        j.SubmitTime,
		JobSummary:        summary,
	}
}

// IsPeriodic returns whether a job is periodic.
func (j *Job) IsPeriodic() bool {
	return j.Periodic != nil
}

// IsPeriodicActive returns whether the job is an active periodic job that will
// create child jobs
func (j *Job) IsPeriodicActive() bool {
	return j.IsPeriodic() && j.Periodic.Enabled && !j.Stopped() && !j.IsParameterized()
}

// IsParameterized returns whether a job is parameterized job.
func (j *Job) IsParameterized() bool {
	return j.ParameterizedJob != nil && !j.Dispatched
}

// VaultPolicies returns the set of Vault policies per task group, per task
func (j *Job) VaultPolicies() map[string]map[string]*Vault {
	policies := make(map[string]map[string]*Vault, len(j.TaskGroups))

	for _, tg := range j.TaskGroups {
		tgPolicies := make(map[string]*Vault, len(tg.Tasks))

		for _, task := range tg.Tasks {
			if task.Vault == nil {
				continue
			}

			tgPolicies[task.Name] = task.Vault
		}

		if len(tgPolicies) != 0 {
			policies[tg.Name] = tgPolicies
		}
	}

	return policies
}

// RequiredSignals returns a mapping of task groups to tasks to their required
// set of signals
func (j *Job) RequiredSignals() map[string]map[string][]string {
	signals := make(map[string]map[string][]string)

	for _, tg := range j.TaskGroups {
		for _, task := range tg.Tasks {
			// Use this local one as a set
			taskSignals := make(map[string]struct{})

			// Check if the Vault change mode uses signals
			if task.Vault != nil && task.Vault.ChangeMode == VaultChangeModeSignal {
				taskSignals[task.Vault.ChangeSignal] = struct{}{}
			}

			// If a user has specified a KillSignal, add it to required signals
			if task.KillSignal != "" {
				taskSignals[task.KillSignal] = struct{}{}
			}

			// Check if any template change mode uses signals
			for _, t := range task.Templates {
				if t.ChangeMode != TemplateChangeModeSignal {
					continue
				}

				taskSignals[t.ChangeSignal] = struct{}{}
			}

			// Flatten and sort the signals
			l := len(taskSignals)
			if l == 0 {
				continue
			}

			flat := make([]string, 0, l)
			for sig := range taskSignals {
				flat = append(flat, sig)
			}

			sort.Strings(flat)
			tgSignals, ok := signals[tg.Name]
			if !ok {
				tgSignals = make(map[string][]string)
				signals[tg.Name] = tgSignals
			}
			tgSignals[task.Name] = flat
		}

	}

	return signals
}

// SpecChanged determines if the functional specification has changed between
// two job versions.
func (j *Job) SpecChanged(new *Job) bool {
	if j == nil {
		return new != nil
	}

	// Create a copy of the new job
	c := new.Copy()

	// Update the new job so we can do a reflect
	c.Status = j.Status
	c.StatusDescription = j.StatusDescription
	c.Stable = j.Stable
	c.Version = j.Version
	c.CreateIndex = j.CreateIndex
	c.ModifyIndex = j.ModifyIndex
	c.JobModifyIndex = j.JobModifyIndex
	c.SubmitTime = j.SubmitTime

	// Deep equals the jobs
	return !reflect.DeepEqual(j, c)
}

func (j *Job) SetSubmitTime() {
	j.SubmitTime = time.Now().UTC().UnixNano()
}

// JobListStub is used to return a subset of job information
// for the job list
type JobListStub struct {
	ID                string
	ParentID          string
	Name              string
	Datacenters       []string
	Type              string
	Priority          int
	Periodic          bool
	ParameterizedJob  bool
	Stop              bool
	Status            string
	StatusDescription string
	JobSummary        *JobSummary
	CreateIndex       uint64
	ModifyIndex       uint64
	JobModifyIndex    uint64
	SubmitTime        int64
}

// JobSummary summarizes the state of the allocations of a job
type JobSummary struct {
	// JobID is the ID of the job the summary is for
	JobID string

	// Namespace is the namespace of the job and its summary
	Namespace string

	// Summary contains the summary per task group for the Job
	Summary map[string]TaskGroupSummary

	// Children contains a summary for the children of this job.
	Children *JobChildrenSummary

	// Raft Indexes
	CreateIndex uint64
	ModifyIndex uint64
}

// Copy returns a new copy of JobSummary
func (js *JobSummary) Copy() *JobSummary {
	newJobSummary := new(JobSummary)
	*newJobSummary = *js
	newTGSummary := make(map[string]TaskGroupSummary, len(js.Summary))
	for k, v := range js.Summary {
		newTGSummary[k] = v
	}
	newJobSummary.Summary = newTGSummary
	newJobSummary.Children = newJobSummary.Children.Copy()
	return newJobSummary
}

// JobChildrenSummary contains the summary of children job statuses
type JobChildrenSummary struct {
	Pending int64
	Running int64
	Dead    int64
}

// Copy returns a new copy of a JobChildrenSummary
func (jc *JobChildrenSummary) Copy() *JobChildrenSummary {
	if jc == nil {
		return nil
	}

	njc := new(JobChildrenSummary)
	*njc = *jc
	return njc
}

// TaskGroup summarizes the state of all the allocations of a particular
// TaskGroup
type TaskGroupSummary struct {
	Queued   int
	Complete int
	Failed   int
	Running  int
	Starting int
	Lost     int
}

const (
	// Checks uses any registered health check state in combination with task
	// states to determine if a allocation is healthy.
	UpdateStrategyHealthCheck_Checks = "checks"

	// TaskStates uses the task states of an allocation to determine if the
	// allocation is healthy.
	UpdateStrategyHealthCheck_TaskStates = "task_states"

	// Manual allows the operator to manually signal to Nomad when an
	// allocations is healthy. This allows more advanced health checking that is
	// outside of the scope of Nomad.
	UpdateStrategyHealthCheck_Manual = "manual"
)

var (
	// DefaultUpdateStrategy provides a baseline that can be used to upgrade
	// jobs with the old policy or for populating field defaults.
	DefaultUpdateStrategy = &UpdateStrategy{
		Stagger:          30 * time.Second,
		MaxParallel:      1,
		HealthCheck:      UpdateStrategyHealthCheck_Checks,
		MinHealthyTime:   10 * time.Second,
		HealthyDeadline:  5 * time.Minute,
		ProgressDeadline: 10 * time.Minute,
		AutoRevert:       false,
		Canary:           0,
	}
)

// UpdateStrategy is used to modify how updates are done
type UpdateStrategy struct {
	// Stagger is used to determine the rate at which allocations are migrated
	// due to down or draining nodes.
	Stagger time.Duration

	// MaxParallel is how many updates can be done in parallel
	MaxParallel int

	// HealthCheck specifies the mechanism in which allocations are marked
	// healthy or unhealthy as part of a deployment.
	HealthCheck string

	// MinHealthyTime is the minimum time an allocation must be in the healthy
	// state before it is marked as healthy, unblocking more allocations to be
	// rolled.
	MinHealthyTime time.Duration

	// HealthyDeadline is the time in which an allocation must be marked as
	// healthy before it is automatically transitioned to unhealthy. This time
	// period doesn't count against the MinHealthyTime.
	HealthyDeadline time.Duration

	// ProgressDeadline is the time in which an allocation as part of the
	// deployment must transition to healthy. If no allocation becomes healthy
	// after the deadline, the deployment is marked as failed. If the deadline
	// is zero, the first failure causes the deployment to fail.
	ProgressDeadline time.Duration

	// AutoRevert declares that if a deployment fails because of unhealthy
	// allocations, there should be an attempt to auto-revert the job to a
	// stable version.
	AutoRevert bool

	// Canary is the number of canaries to deploy when a change to the task
	// group is detected.
	Canary int
}

func (u *UpdateStrategy) Copy() *UpdateStrategy {
	if u == nil {
		return nil
	}

	copy := new(UpdateStrategy)
	*copy = *u
	return copy
}

func (u *UpdateStrategy) Validate() error {
	if u == nil {
		return nil
	}

	var mErr multierror.Error
	switch u.HealthCheck {
	case UpdateStrategyHealthCheck_Checks, UpdateStrategyHealthCheck_TaskStates, UpdateStrategyHealthCheck_Manual:
	default:
		multierror.Append(&mErr, fmt.Errorf("Invalid health check given: %q", u.HealthCheck))
	}

	if u.MaxParallel < 1 {
		multierror.Append(&mErr, fmt.Errorf("Max parallel can not be less than one: %d < 1", u.MaxParallel))
	}
	if u.Canary < 0 {
		multierror.Append(&mErr, fmt.Errorf("Canary count can not be less than zero: %d < 0", u.Canary))
	}
	if u.MinHealthyTime < 0 {
		multierror.Append(&mErr, fmt.Errorf("Minimum healthy time may not be less than zero: %v", u.MinHealthyTime))
	}
	if u.HealthyDeadline <= 0 {
		multierror.Append(&mErr, fmt.Errorf("Healthy deadline must be greater than zero: %v", u.HealthyDeadline))
	}
	if u.ProgressDeadline < 0 {
		multierror.Append(&mErr, fmt.Errorf("Progress deadline must be zero or greater: %v", u.ProgressDeadline))
	}
	if u.MinHealthyTime >= u.HealthyDeadline {
		multierror.Append(&mErr, fmt.Errorf("Minimum healthy time must be less than healthy deadline: %v > %v", u.MinHealthyTime, u.HealthyDeadline))
	}
	if u.ProgressDeadline != 0 && u.HealthyDeadline >= u.ProgressDeadline {
		multierror.Append(&mErr, fmt.Errorf("Healthy deadline must be less than progress deadline: %v > %v", u.HealthyDeadline, u.ProgressDeadline))
	}
	if u.Stagger <= 0 {
		multierror.Append(&mErr, fmt.Errorf("Stagger must be greater than zero: %v", u.Stagger))
	}

	return mErr.ErrorOrNil()
}

// TODO(alexdadgar): Remove once no longer used by the scheduler.
// Rolling returns if a rolling strategy should be used
func (u *UpdateStrategy) Rolling() bool {
	return u.Stagger > 0 && u.MaxParallel > 0
}

const (
	// PeriodicSpecCron is used for a cron spec.
	PeriodicSpecCron = "cron"

	// PeriodicSpecTest is only used by unit tests. It is a sorted, comma
	// separated list of unix timestamps at which to launch.
	PeriodicSpecTest = "_internal_test"
)

// Periodic defines the interval a job should be run at.
type PeriodicConfig struct {
	// Enabled determines if the job should be run periodically.
	Enabled bool

	// Spec specifies the interval the job should be run as. It is parsed based
	// on the SpecType.
	Spec string

	// SpecType defines the format of the spec.
	SpecType string

	// ProhibitOverlap enforces that spawned jobs do not run in parallel.
	ProhibitOverlap bool

	// TimeZone is the user specified string that determines the time zone to
	// launch against. The time zones must be specified from IANA Time Zone
	// database, such as "America/New_York".
	// Reference: https://en.wikipedia.org/wiki/List_of_tz_database_time_zones
	// Reference: https://www.iana.org/time-zones
	TimeZone string

	// location is the time zone to evaluate the launch time against
	location *time.Location
}

func (p *PeriodicConfig) Copy() *PeriodicConfig {
	if p == nil {
		return nil
	}
	np := new(PeriodicConfig)
	*np = *p
	return np
}

func (p *PeriodicConfig) Validate() error {
	if !p.Enabled {
		return nil
	}

	var mErr multierror.Error
	if p.Spec == "" {
		multierror.Append(&mErr, fmt.Errorf("Must specify a spec"))
	}

	// Check if we got a valid time zone
	if p.TimeZone != "" {
		if _, err := time.LoadLocation(p.TimeZone); err != nil {
			multierror.Append(&mErr, fmt.Errorf("Invalid time zone %q: %v", p.TimeZone, err))
		}
	}

	switch p.SpecType {
	case PeriodicSpecCron:
		// Validate the cron spec
		if _, err := cronexpr.Parse(p.Spec); err != nil {
			multierror.Append(&mErr, fmt.Errorf("Invalid cron spec %q: %v", p.Spec, err))
		}
	case PeriodicSpecTest:
		// No-op
	default:
		multierror.Append(&mErr, fmt.Errorf("Unknown periodic specification type %q", p.SpecType))
	}

	return mErr.ErrorOrNil()
}

func (p *PeriodicConfig) Canonicalize() {
	// Load the location
	l, err := time.LoadLocation(p.TimeZone)
	if err != nil {
		p.location = time.UTC
	}

	p.location = l
}

// CronParseNext is a helper that parses the next time for the given expression
// but captures any panic that may occur in the underlying library.
func CronParseNext(e *cronexpr.Expression, fromTime time.Time, spec string) (t time.Time, err error) {
	defer func() {
		if recover() != nil {
			t = time.Time{}
			err = fmt.Errorf("failed parsing cron expression: %q", spec)
		}
	}()

	return e.Next(fromTime), nil
}

// Next returns the closest time instant matching the spec that is after the
// passed time. If no matching instance exists, the zero value of time.Time is
// returned. The `time.Location` of the returned value matches that of the
// passed time.
func (p *PeriodicConfig) Next(fromTime time.Time) (time.Time, error) {
	switch p.SpecType {
	case PeriodicSpecCron:
		if e, err := cronexpr.Parse(p.Spec); err == nil {
			return CronParseNext(e, fromTime, p.Spec)
		}
	case PeriodicSpecTest:
		split := strings.Split(p.Spec, ",")
		if len(split) == 1 && split[0] == "" {
			return time.Time{}, nil
		}

		// Parse the times
		times := make([]time.Time, len(split))
		for i, s := range split {
			unix, err := strconv.Atoi(s)
			if err != nil {
				return time.Time{}, nil
			}

			times[i] = time.Unix(int64(unix), 0)
		}

		// Find the next match
		for _, next := range times {
			if fromTime.Before(next) {
				return next, nil
			}
		}
	}

	return time.Time{}, nil
}

// GetLocation returns the location to use for determining the time zone to run
// the periodic job against.
func (p *PeriodicConfig) GetLocation() *time.Location {
	// Jobs pre 0.5.5 will not have this
	if p.location != nil {
		return p.location
	}

	return time.UTC
}

const (
	// PeriodicLaunchSuffix is the string appended to the periodic jobs ID
	// when launching derived instances of it.
	PeriodicLaunchSuffix = "/periodic-"
)

// PeriodicLaunch tracks the last launch time of a periodic job.
type PeriodicLaunch struct {
	ID        string    // ID of the periodic job.
	Namespace string    // Namespace of the periodic job
	Launch    time.Time // The last launch time.

	// Raft Indexes
	CreateIndex uint64
	ModifyIndex uint64
}

const (
	DispatchPayloadForbidden = "forbidden"
	DispatchPayloadOptional  = "optional"
	DispatchPayloadRequired  = "required"

	// DispatchLaunchSuffix is the string appended to the parameterized job's ID
	// when dispatching instances of it.
	DispatchLaunchSuffix = "/dispatch-"
)

// ParameterizedJobConfig is used to configure the parameterized job
type ParameterizedJobConfig struct {
	// Payload configure the payload requirements
	Payload string

	// MetaRequired is metadata keys that must be specified by the dispatcher
	MetaRequired []string

	// MetaOptional is metadata keys that may be specified by the dispatcher
	MetaOptional []string
}

func (d *ParameterizedJobConfig) Validate() error {
	var mErr multierror.Error
	switch d.Payload {
	case DispatchPayloadOptional, DispatchPayloadRequired, DispatchPayloadForbidden:
	default:
		multierror.Append(&mErr, fmt.Errorf("Unknown payload requirement: %q", d.Payload))
	}

	// Check that the meta configurations are disjoint sets
	disjoint, offending := helper.SliceSetDisjoint(d.MetaRequired, d.MetaOptional)
	if !disjoint {
		multierror.Append(&mErr, fmt.Errorf("Required and optional meta keys should be disjoint. Following keys exist in both: %v", offending))
	}

	return mErr.ErrorOrNil()
}

func (d *ParameterizedJobConfig) Canonicalize() {
	if d.Payload == "" {
		d.Payload = DispatchPayloadOptional
	}
}

func (d *ParameterizedJobConfig) Copy() *ParameterizedJobConfig {
	if d == nil {
		return nil
	}
	nd := new(ParameterizedJobConfig)
	*nd = *d
	nd.MetaOptional = helper.CopySliceString(nd.MetaOptional)
	nd.MetaRequired = helper.CopySliceString(nd.MetaRequired)
	return nd
}

// DispatchedID returns an ID appropriate for a job dispatched against a
// particular parameterized job
func DispatchedID(templateID string, t time.Time) string {
	u := uuid.Generate()[:8]
	return fmt.Sprintf("%s%s%d-%s", templateID, DispatchLaunchSuffix, t.Unix(), u)
}

// DispatchPayloadConfig configures how a task gets its input from a job dispatch
type DispatchPayloadConfig struct {
	// File specifies a relative path to where the input data should be written
	File string
}

func (d *DispatchPayloadConfig) Copy() *DispatchPayloadConfig {
	if d == nil {
		return nil
	}
	nd := new(DispatchPayloadConfig)
	*nd = *d
	return nd
}

func (d *DispatchPayloadConfig) Validate() error {
	// Verify the destination doesn't escape
	escaped, err := PathEscapesAllocDir("task/local/", d.File)
	if err != nil {
		return fmt.Errorf("invalid destination path: %v", err)
	} else if escaped {
		return fmt.Errorf("destination escapes allocation directory")
	}

	return nil
}

var (
	// These default restart policies needs to be in sync with
	// Canonicalize in api/tasks.go

	DefaultServiceJobRestartPolicy = RestartPolicy{
		Delay:    15 * time.Second,
		Attempts: 2,
		Interval: 30 * time.Minute,
		Mode:     RestartPolicyModeFail,
	}
	DefaultBatchJobRestartPolicy = RestartPolicy{
		Delay:    15 * time.Second,
		Attempts: 3,
		Interval: 24 * time.Hour,
		Mode:     RestartPolicyModeFail,
	}
)

var (
	// These default reschedule policies needs to be in sync with
	// NewDefaultReschedulePolicy in api/tasks.go

	DefaultServiceJobReschedulePolicy = ReschedulePolicy{
		Delay:         30 * time.Second,
		DelayFunction: "exponential",
		MaxDelay:      1 * time.Hour,
		Unlimited:     true,
	}
	DefaultBatchJobReschedulePolicy = ReschedulePolicy{
		Attempts:      1,
		Interval:      24 * time.Hour,
		Delay:         5 * time.Second,
		DelayFunction: "constant",
	}
)

const (
	// RestartPolicyModeDelay causes an artificial delay till the next interval is
	// reached when the specified attempts have been reached in the interval.
	RestartPolicyModeDelay = "delay"

	// RestartPolicyModeFail causes a job to fail if the specified number of
	// attempts are reached within an interval.
	RestartPolicyModeFail = "fail"

	// RestartPolicyMinInterval is the minimum interval that is accepted for a
	// restart policy.
	RestartPolicyMinInterval = 5 * time.Second

	// ReasonWithinPolicy describes restart events that are within policy
	ReasonWithinPolicy = "Restart within policy"
)

// RestartPolicy configures how Tasks are restarted when they crash or fail.
type RestartPolicy struct {
	// Attempts is the number of restart that will occur in an interval.
	Attempts int

	// Interval is a duration in which we can limit the number of restarts
	// within.
	Interval time.Duration

	// Delay is the time between a failure and a restart.
	Delay time.Duration

	// Mode controls what happens when the task restarts more than attempt times
	// in an interval.
	Mode string
}

func (r *RestartPolicy) Copy() *RestartPolicy {
	if r == nil {
		return nil
	}
	nrp := new(RestartPolicy)
	*nrp = *r
	return nrp
}

func (r *RestartPolicy) Validate() error {
	var mErr multierror.Error
	switch r.Mode {
	case RestartPolicyModeDelay, RestartPolicyModeFail:
	default:
		multierror.Append(&mErr, fmt.Errorf("Unsupported restart mode: %q", r.Mode))
	}

	// Check for ambiguous/confusing settings
	if r.Attempts == 0 && r.Mode != RestartPolicyModeFail {
		multierror.Append(&mErr, fmt.Errorf("Restart policy %q with %d attempts is ambiguous", r.Mode, r.Attempts))
	}

	if r.Interval.Nanoseconds() < RestartPolicyMinInterval.Nanoseconds() {
		multierror.Append(&mErr, fmt.Errorf("Interval can not be less than %v (got %v)", RestartPolicyMinInterval, r.Interval))
	}
	if time.Duration(r.Attempts)*r.Delay > r.Interval {
		multierror.Append(&mErr,
			fmt.Errorf("Nomad can't restart the TaskGroup %v times in an interval of %v with a delay of %v", r.Attempts, r.Interval, r.Delay))
	}
	return mErr.ErrorOrNil()
}

func NewRestartPolicy(jobType string) *RestartPolicy {
	switch jobType {
	case JobTypeService, JobTypeSystem:
		rp := DefaultServiceJobRestartPolicy
		return &rp
	case JobTypeBatch:
		rp := DefaultBatchJobRestartPolicy
		return &rp
	}
	return nil
}

const ReschedulePolicyMinInterval = 15 * time.Second
const ReschedulePolicyMinDelay = 5 * time.Second

var RescheduleDelayFunctions = [...]string{"constant", "exponential", "fibonacci"}

// ReschedulePolicy configures how Tasks are rescheduled  when they crash or fail.
type ReschedulePolicy struct {
	// Attempts limits the number of rescheduling attempts that can occur in an interval.
	Attempts int

	// Interval is a duration in which we can limit the number of reschedule attempts.
	Interval time.Duration

	// Delay is a minimum duration to wait between reschedule attempts.
	// The delay function determines how much subsequent reschedule attempts are delayed by.
	Delay time.Duration

	// DelayFunction determines how the delay progressively changes on subsequent reschedule
	// attempts. Valid values are "exponential", "constant", and "fibonacci".
	DelayFunction string

	// MaxDelay is an upper bound on the delay.
	MaxDelay time.Duration

	// Unlimited allows infinite rescheduling attempts. Only allowed when delay is set
	// between reschedule attempts.
	Unlimited bool
}

func (r *ReschedulePolicy) Copy() *ReschedulePolicy {
	if r == nil {
		return nil
	}
	nrp := new(ReschedulePolicy)
	*nrp = *r
	return nrp
}

func (r *ReschedulePolicy) Enabled() bool {
	enabled := r != nil && (r.Attempts > 0 || r.Unlimited)
	return enabled
}

// Validate uses different criteria to validate the reschedule policy
// Delay must be a minimum of 5 seconds
// Delay Ceiling is ignored if Delay Function is "constant"
// Number of possible attempts is validated, given the interval, delay and delay function
func (r *ReschedulePolicy) Validate() error {
	if !r.Enabled() {
		return nil
	}
	var mErr multierror.Error
	// Check for ambiguous/confusing settings
	if r.Attempts > 0 {
		if r.Interval <= 0 {
			multierror.Append(&mErr, fmt.Errorf("Interval must be a non zero value if Attempts > 0"))
		}
		if r.Unlimited {
			multierror.Append(&mErr, fmt.Errorf("Reschedule Policy with Attempts = %v, Interval = %v, "+
				"and Unlimited = %v is ambiguous", r.Attempts, r.Interval, r.Unlimited))
			multierror.Append(&mErr, errors.New("If Attempts >0, Unlimited cannot also be set to true"))
		}
	}

	delayPreCheck := true
	// Delay should be bigger than the default
	if r.Delay.Nanoseconds() < ReschedulePolicyMinDelay.Nanoseconds() {
		multierror.Append(&mErr, fmt.Errorf("Delay cannot be less than %v (got %v)", ReschedulePolicyMinDelay, r.Delay))
		delayPreCheck = false
	}

	// Must use a valid delay function
	if !isValidDelayFunction(r.DelayFunction) {
		multierror.Append(&mErr, fmt.Errorf("Invalid delay function %q, must be one of %q", r.DelayFunction, RescheduleDelayFunctions))
		delayPreCheck = false
	}

	// Validate MaxDelay if not using linear delay progression
	if r.DelayFunction != "constant" {
		if r.MaxDelay.Nanoseconds() < ReschedulePolicyMinDelay.Nanoseconds() {
			multierror.Append(&mErr, fmt.Errorf("Max Delay cannot be less than %v (got %v)", ReschedulePolicyMinDelay, r.Delay))
			delayPreCheck = false
		}
		if r.MaxDelay < r.Delay {
			multierror.Append(&mErr, fmt.Errorf("Max Delay cannot be less than Delay %v (got %v)", r.Delay, r.MaxDelay))
			delayPreCheck = false
		}

	}

	// Validate Interval and other delay parameters if attempts are limited
	if !r.Unlimited {
		if r.Interval.Nanoseconds() < ReschedulePolicyMinInterval.Nanoseconds() {
			multierror.Append(&mErr, fmt.Errorf("Interval cannot be less than %v (got %v)", ReschedulePolicyMinInterval, r.Interval))
		}
		if !delayPreCheck {
			// We can't cross validate the rest of the delay params if delayPreCheck fails, so return early
			return mErr.ErrorOrNil()
		}
		crossValidationErr := r.validateDelayParams()
		if crossValidationErr != nil {
			multierror.Append(&mErr, crossValidationErr)
		}
	}
	return mErr.ErrorOrNil()
}

func isValidDelayFunction(delayFunc string) bool {
	for _, value := range RescheduleDelayFunctions {
		if value == delayFunc {
			return true
		}
	}
	return false
}

func (r *ReschedulePolicy) validateDelayParams() error {
	ok, possibleAttempts, recommendedInterval := r.viableAttempts()
	if ok {
		return nil
	}
	var mErr multierror.Error
	if r.DelayFunction == "constant" {
		multierror.Append(&mErr, fmt.Errorf("Nomad can only make %v attempts in %v with initial delay %v and "+
			"delay function %q", possibleAttempts, r.Interval, r.Delay, r.DelayFunction))
	} else {
		multierror.Append(&mErr, fmt.Errorf("Nomad can only make %v attempts in %v with initial delay %v, "+
			"delay function %q, and delay ceiling %v", possibleAttempts, r.Interval, r.Delay, r.DelayFunction, r.MaxDelay))
	}
	multierror.Append(&mErr, fmt.Errorf("Set the interval to at least %v to accommodate %v attempts", recommendedInterval.Round(time.Second), r.Attempts))
	return mErr.ErrorOrNil()
}

func (r *ReschedulePolicy) viableAttempts() (bool, int, time.Duration) {
	var possibleAttempts int
	var recommendedInterval time.Duration
	valid := true
	switch r.DelayFunction {
	case "constant":
		recommendedInterval = time.Duration(r.Attempts) * r.Delay
		if r.Interval < recommendedInterval {
			possibleAttempts = int(r.Interval / r.Delay)
			valid = false
		}
	case "exponential":
		for i := 0; i < r.Attempts; i++ {
			nextDelay := time.Duration(math.Pow(2, float64(i))) * r.Delay
			if nextDelay > r.MaxDelay {
				nextDelay = r.MaxDelay
				recommendedInterval += nextDelay
			} else {
				recommendedInterval = nextDelay
			}
			if recommendedInterval < r.Interval {
				possibleAttempts++
			}
		}
		if possibleAttempts < r.Attempts {
			valid = false
		}
	case "fibonacci":
		var slots []time.Duration
		slots = append(slots, r.Delay)
		slots = append(slots, r.Delay)
		reachedCeiling := false
		for i := 2; i < r.Attempts; i++ {
			var nextDelay time.Duration
			if reachedCeiling {
				//switch to linear
				nextDelay = slots[i-1] + r.MaxDelay
			} else {
				nextDelay = slots[i-1] + slots[i-2]
				if nextDelay > r.MaxDelay {
					nextDelay = r.MaxDelay
					reachedCeiling = true
				}
			}
			slots = append(slots, nextDelay)
		}
		recommendedInterval = slots[len(slots)-1]
		if r.Interval < recommendedInterval {
			valid = false
			// calculate possible attempts
			for i := 0; i < len(slots); i++ {
				if slots[i] > r.Interval {
					possibleAttempts = i
					break
				}
			}
		}
	default:
		return false, 0, 0
	}
	if possibleAttempts < 0 { // can happen if delay is bigger than interval
		possibleAttempts = 0
	}
	return valid, possibleAttempts, recommendedInterval
}

func NewReschedulePolicy(jobType string) *ReschedulePolicy {
	switch jobType {
	case JobTypeService:
		rp := DefaultServiceJobReschedulePolicy
		return &rp
	case JobTypeBatch:
		rp := DefaultBatchJobReschedulePolicy
		return &rp
	}
	return nil
}

const (
	MigrateStrategyHealthChecks = "checks"
	MigrateStrategyHealthStates = "task_states"
)

type MigrateStrategy struct {
	MaxParallel     int
	HealthCheck     string
	MinHealthyTime  time.Duration
	HealthyDeadline time.Duration
}

// DefaultMigrateStrategy is used for backwards compat with pre-0.8 Allocations
// that lack an update strategy.
//
// This function should match its counterpart in api/tasks.go
func DefaultMigrateStrategy() *MigrateStrategy {
	return &MigrateStrategy{
		MaxParallel:     1,
		HealthCheck:     MigrateStrategyHealthChecks,
		MinHealthyTime:  10 * time.Second,
		HealthyDeadline: 5 * time.Minute,
	}
}

func (m *MigrateStrategy) Validate() error {
	var mErr multierror.Error

	if m.MaxParallel < 0 {
		multierror.Append(&mErr, fmt.Errorf("MaxParallel must be >= 0 but found %d", m.MaxParallel))
	}

	switch m.HealthCheck {
	case MigrateStrategyHealthChecks, MigrateStrategyHealthStates:
		// ok
	case "":
		if m.MaxParallel > 0 {
			multierror.Append(&mErr, fmt.Errorf("Missing HealthCheck"))
		}
	default:
		multierror.Append(&mErr, fmt.Errorf("Invalid HealthCheck: %q", m.HealthCheck))
	}

	if m.MinHealthyTime < 0 {
		multierror.Append(&mErr, fmt.Errorf("MinHealthyTime is %s and must be >= 0", m.MinHealthyTime))
	}

	if m.HealthyDeadline < 0 {
		multierror.Append(&mErr, fmt.Errorf("HealthyDeadline is %s and must be >= 0", m.HealthyDeadline))
	}

	if m.MinHealthyTime > m.HealthyDeadline {
		multierror.Append(&mErr, fmt.Errorf("MinHealthyTime must be less than HealthyDeadline"))
	}

	return mErr.ErrorOrNil()
}

// TaskGroup is an atomic unit of placement. Each task group belongs to
// a job and may contain any number of tasks. A task group support running
// in many replicas using the same configuration..
type TaskGroup struct {
	// Name of the task group
	Name string

	// Count is the number of replicas of this task group that should
	// be scheduled.
	Count int

	// Update is used to control the update strategy for this task group
	Update *UpdateStrategy

	// Migrate is used to control the migration strategy for this task group
	Migrate *MigrateStrategy

	// Constraints can be specified at a task group level and apply to
	// all the tasks contained.
	Constraints []*Constraint

	//RestartPolicy of a TaskGroup
	RestartPolicy *RestartPolicy

	// Tasks are the collection of tasks that this task group needs to run
	Tasks []*Task

	// EphemeralDisk is the disk resources that the task group requests
	EphemeralDisk *EphemeralDisk

	// Meta is used to associate arbitrary metadata with this
	// task group. This is opaque to Nomad.
	Meta map[string]string

	// ReschedulePolicy is used to configure how the scheduler should
	// retry failed allocations.
	ReschedulePolicy *ReschedulePolicy

	// Affinities can be specified at the task group level to express
	// scheduling preferences.
	Affinities []*Affinity

	// Spread can be specified at the task group level to express spreading
	// allocations across a desired attribute, such as datacenter
	Spreads []*Spread
}

func (tg *TaskGroup) Copy() *TaskGroup {
	if tg == nil {
		return nil
	}
	ntg := new(TaskGroup)
	*ntg = *tg
	ntg.Update = ntg.Update.Copy()
	ntg.Constraints = CopySliceConstraints(ntg.Constraints)
	ntg.RestartPolicy = ntg.RestartPolicy.Copy()
	ntg.ReschedulePolicy = ntg.ReschedulePolicy.Copy()
	ntg.Affinities = CopySliceAffinities(ntg.Affinities)
	ntg.Spreads = CopySliceSpreads(ntg.Spreads)

	if tg.Tasks != nil {
		tasks := make([]*Task, len(ntg.Tasks))
		for i, t := range ntg.Tasks {
			tasks[i] = t.Copy()
		}
		ntg.Tasks = tasks
	}

	ntg.Meta = helper.CopyMapStringString(ntg.Meta)

	if tg.EphemeralDisk != nil {
		ntg.EphemeralDisk = tg.EphemeralDisk.Copy()
	}
	return ntg
}

// Canonicalize is used to canonicalize fields in the TaskGroup.
func (tg *TaskGroup) Canonicalize(job *Job) {
	// Ensure that an empty and nil map are treated the same to avoid scheduling
	// problems since we use reflect DeepEquals.
	if len(tg.Meta) == 0 {
		tg.Meta = nil
	}

	// Set the default restart policy.
	if tg.RestartPolicy == nil {
		tg.RestartPolicy = NewRestartPolicy(job.Type)
	}

	if tg.ReschedulePolicy == nil {
		tg.ReschedulePolicy = NewReschedulePolicy(job.Type)
	}

	// Canonicalize Migrate for service jobs
	if job.Type == JobTypeService && tg.Migrate == nil {
		tg.Migrate = DefaultMigrateStrategy()
	}

	// Set a default ephemeral disk object if the user has not requested for one
	if tg.EphemeralDisk == nil {
		tg.EphemeralDisk = DefaultEphemeralDisk()
	}

	for _, task := range tg.Tasks {
		task.Canonicalize(job, tg)
	}
}

// Validate is used to sanity check a task group
func (tg *TaskGroup) Validate(j *Job) error {
	var mErr multierror.Error
	if tg.Name == "" {
		mErr.Errors = append(mErr.Errors, errors.New("Missing task group name"))
	}
	if tg.Count < 0 {
		mErr.Errors = append(mErr.Errors, errors.New("Task group count can't be negative"))
	}
	if len(tg.Tasks) == 0 {
		mErr.Errors = append(mErr.Errors, errors.New("Missing tasks for task group"))
	}
	for idx, constr := range tg.Constraints {
		if err := constr.Validate(); err != nil {
			outer := fmt.Errorf("Constraint %d validation failed: %s", idx+1, err)
			mErr.Errors = append(mErr.Errors, outer)
		}
	}
	if j.Type == JobTypeSystem {
		if tg.Affinities != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("System jobs may not have an affinity stanza"))
		}
	} else {
		for idx, affinity := range tg.Affinities {
			if err := affinity.Validate(); err != nil {
				outer := fmt.Errorf("Affinity %d validation failed: %s", idx+1, err)
				mErr.Errors = append(mErr.Errors, outer)
			}
		}
	}

	if tg.RestartPolicy != nil {
		if err := tg.RestartPolicy.Validate(); err != nil {
			mErr.Errors = append(mErr.Errors, err)
		}
	} else {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("Task Group %v should have a restart policy", tg.Name))
	}

	if j.Type == JobTypeSystem {
		if tg.Spreads != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("System jobs may not have a spread stanza"))
		}
	} else {
		for idx, spread := range tg.Spreads {
			if err := spread.Validate(); err != nil {
				outer := fmt.Errorf("Spread %d validation failed: %s", idx+1, err)
				mErr.Errors = append(mErr.Errors, outer)
			}
		}
	}

	if j.Type == JobTypeSystem {
		if tg.ReschedulePolicy != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("System jobs should not have a reschedule policy"))
		}
	} else {
		if tg.ReschedulePolicy != nil {
			if err := tg.ReschedulePolicy.Validate(); err != nil {
				mErr.Errors = append(mErr.Errors, err)
			}
		} else {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Task Group %v should have a reschedule policy", tg.Name))
		}
	}

	if tg.EphemeralDisk != nil {
		if err := tg.EphemeralDisk.Validate(); err != nil {
			mErr.Errors = append(mErr.Errors, err)
		}
	} else {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("Task Group %v should have an ephemeral disk object", tg.Name))
	}

	// Validate the update strategy
	if u := tg.Update; u != nil {
		switch j.Type {
		case JobTypeService, JobTypeSystem:
		default:
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Job type %q does not allow update block", j.Type))
		}
		if err := u.Validate(); err != nil {
			mErr.Errors = append(mErr.Errors, err)
		}
	}

	// Validate the migration strategy
	switch j.Type {
	case JobTypeService:
		if tg.Migrate != nil {
			if err := tg.Migrate.Validate(); err != nil {
				mErr.Errors = append(mErr.Errors, err)
			}
		}
	default:
		if tg.Migrate != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Job type %q does not allow migrate block", j.Type))
		}
	}

	// Check for duplicate tasks, that there is only leader task if any,
	// and no duplicated static ports
	tasks := make(map[string]int)
	staticPorts := make(map[int]string)
	leaderTasks := 0
	for idx, task := range tg.Tasks {
		if task.Name == "" {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Task %d missing name", idx+1))
		} else if existing, ok := tasks[task.Name]; ok {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Task %d redefines '%s' from task %d", idx+1, task.Name, existing+1))
		} else {
			tasks[task.Name] = idx
		}

		if task.Leader {
			leaderTasks++
		}

		if task.Resources == nil {
			continue
		}

		for _, net := range task.Resources.Networks {
			for _, port := range net.ReservedPorts {
				if other, ok := staticPorts[port.Value]; ok {
					err := fmt.Errorf("Static port %d already reserved by %s", port.Value, other)
					mErr.Errors = append(mErr.Errors, err)
				} else {
					staticPorts[port.Value] = fmt.Sprintf("%s:%s", task.Name, port.Label)
				}
			}
		}
	}

	if leaderTasks > 1 {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("Only one task may be marked as leader"))
	}

	// Validate the tasks
	for _, task := range tg.Tasks {
		if err := task.Validate(tg.EphemeralDisk, j.Type); err != nil {
			outer := fmt.Errorf("Task %s validation failed: %v", task.Name, err)
			mErr.Errors = append(mErr.Errors, outer)
		}
	}
	return mErr.ErrorOrNil()
}

// Warnings returns a list of warnings that may be from dubious settings or
// deprecation warnings.
func (tg *TaskGroup) Warnings(j *Job) error {
	var mErr multierror.Error

	// Validate the update strategy
	if u := tg.Update; u != nil {
		// Check the counts are appropriate
		if u.MaxParallel > tg.Count {
			mErr.Errors = append(mErr.Errors,
				fmt.Errorf("Update max parallel count is greater than task group count (%d > %d). "+
					"A destructive change would result in the simultaneous replacement of all allocations.", u.MaxParallel, tg.Count))
		}
	}

	for _, t := range tg.Tasks {
		if err := t.Warnings(); err != nil {
			err = multierror.Prefix(err, fmt.Sprintf("Task %q:", t.Name))
			mErr.Errors = append(mErr.Errors, err)
		}
	}

	return mErr.ErrorOrNil()
}

// LookupTask finds a task by name
func (tg *TaskGroup) LookupTask(name string) *Task {
	for _, t := range tg.Tasks {
		if t.Name == name {
			return t
		}
	}
	return nil
}

func (tg *TaskGroup) GoString() string {
	return fmt.Sprintf("*%#v", *tg)
}

// CheckRestart describes if and when a task should be restarted based on
// failing health checks.
type CheckRestart struct {
	Limit          int           // Restart task after this many unhealthy intervals
	Grace          time.Duration // Grace time to give tasks after starting to get healthy
	IgnoreWarnings bool          // If true treat checks in `warning` as passing
}

func (c *CheckRestart) Copy() *CheckRestart {
	if c == nil {
		return nil
	}

	nc := new(CheckRestart)
	*nc = *c
	return nc
}

func (c *CheckRestart) Validate() error {
	if c == nil {
		return nil
	}

	var mErr multierror.Error
	if c.Limit < 0 {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("limit must be greater than or equal to 0 but found %d", c.Limit))
	}

	if c.Grace < 0 {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("grace period must be greater than or equal to 0 but found %d", c.Grace))
	}

	return mErr.ErrorOrNil()
}

const (
	ServiceCheckHTTP   = "http"
	ServiceCheckTCP    = "tcp"
	ServiceCheckScript = "script"
	ServiceCheckGRPC   = "grpc"

	// minCheckInterval is the minimum check interval permitted.  Consul
	// currently has its MinInterval set to 1s.  Mirror that here for
	// consistency.
	minCheckInterval = 1 * time.Second

	// minCheckTimeout is the minimum check timeout permitted for Consul
	// script TTL checks.
	minCheckTimeout = 1 * time.Second
)

// The ServiceCheck data model represents the consul health check that
// Nomad registers for a Task
type ServiceCheck struct {
	Name          string              // Name of the check, defaults to id
	Type          string              // Type of the check - tcp, http, docker and script
	Command       string              // Command is the command to run for script checks
	Args          []string            // Args is a list of arguments for script checks
	Path          string              // path of the health check url for http type check
	Protocol      string              // Protocol to use if check is http, defaults to http
	PortLabel     string              // The port to use for tcp/http checks
	AddressMode   string              // 'host' to use host ip:port or 'driver' to use driver's
	Interval      time.Duration       // Interval of the check
	Timeout       time.Duration       // Timeout of the response from the check before consul fails the check
	InitialStatus string              // Initial status of the check
	TLSSkipVerify bool                // Skip TLS verification when Protocol=https
	Method        string              // HTTP Method to use (GET by default)
	Header        map[string][]string // HTTP Headers for Consul to set when making HTTP checks
	CheckRestart  *CheckRestart       // If and when a task should be restarted based on checks
	GRPCService   string              // Service for GRPC checks
	GRPCUseTLS    bool                // Whether or not to use TLS for GRPC checks
}

func (sc *ServiceCheck) Copy() *ServiceCheck {
	if sc == nil {
		return nil
	}
	nsc := new(ServiceCheck)
	*nsc = *sc
	nsc.Args = helper.CopySliceString(sc.Args)
	nsc.Header = helper.CopyMapStringSliceString(sc.Header)
	nsc.CheckRestart = sc.CheckRestart.Copy()
	return nsc
}

func (sc *ServiceCheck) Canonicalize(serviceName string) {
	// Ensure empty maps/slices are treated as null to avoid scheduling
	// issues when using DeepEquals.
	if len(sc.Args) == 0 {
		sc.Args = nil
	}

	if len(sc.Header) == 0 {
		sc.Header = nil
	} else {
		for k, v := range sc.Header {
			if len(v) == 0 {
				sc.Header[k] = nil
			}
		}
	}

	if sc.Name == "" {
		sc.Name = fmt.Sprintf("service: %q check", serviceName)
	}
}

// validate a Service's ServiceCheck
func (sc *ServiceCheck) validate() error {
	// Validate Type
	switch strings.ToLower(sc.Type) {
	case ServiceCheckGRPC:
	case ServiceCheckTCP:
	case ServiceCheckHTTP:
		if sc.Path == "" {
			return fmt.Errorf("http type must have a valid http path")
		}
		url, err := url.Parse(sc.Path)
		if err != nil {
			return fmt.Errorf("http type must have a valid http path")
		}
		if url.IsAbs() {
			return fmt.Errorf("http type must have a relative http path")
		}

	case ServiceCheckScript:
		if sc.Command == "" {
			return fmt.Errorf("script type must have a valid script path")
		}

	default:
		return fmt.Errorf(`invalid type (%+q), must be one of "http", "tcp", or "script" type`, sc.Type)
	}

	// Validate interval and timeout
	if sc.Interval == 0 {
		return fmt.Errorf("missing required value interval. Interval cannot be less than %v", minCheckInterval)
	} else if sc.Interval < minCheckInterval {
		return fmt.Errorf("interval (%v) cannot be lower than %v", sc.Interval, minCheckInterval)
	}

	if sc.Timeout == 0 {
		return fmt.Errorf("missing required value timeout. Timeout cannot be less than %v", minCheckInterval)
	} else if sc.Timeout < minCheckTimeout {
		return fmt.Errorf("timeout (%v) is lower than required minimum timeout %v", sc.Timeout, minCheckInterval)
	}

	// Validate InitialStatus
	switch sc.InitialStatus {
	case "":
	case api.HealthPassing:
	case api.HealthWarning:
	case api.HealthCritical:
	default:
		return fmt.Errorf(`invalid initial check state (%s), must be one of %q, %q, %q or empty`, sc.InitialStatus, api.HealthPassing, api.HealthWarning, api.HealthCritical)

	}

	// Validate AddressMode
	switch sc.AddressMode {
	case "", AddressModeHost, AddressModeDriver:
		// Ok
	case AddressModeAuto:
		return fmt.Errorf("invalid address_mode %q - %s only valid for services", sc.AddressMode, AddressModeAuto)
	default:
		return fmt.Errorf("invalid address_mode %q", sc.AddressMode)
	}

	return sc.CheckRestart.Validate()
}

// RequiresPort returns whether the service check requires the task has a port.
func (sc *ServiceCheck) RequiresPort() bool {
	switch sc.Type {
	case ServiceCheckGRPC, ServiceCheckHTTP, ServiceCheckTCP:
		return true
	default:
		return false
	}
}

// TriggersRestarts returns true if this check should be watched and trigger a restart
// on failure.
func (sc *ServiceCheck) TriggersRestarts() bool {
	return sc.CheckRestart != nil && sc.CheckRestart.Limit > 0
}

// Hash all ServiceCheck fields and the check's corresponding service ID to
// create an identifier. The identifier is not guaranteed to be unique as if
// the PortLabel is blank, the Service's PortLabel will be used after Hash is
// called.
func (sc *ServiceCheck) Hash(serviceID string) string {
	h := sha1.New()
	io.WriteString(h, serviceID)
	io.WriteString(h, sc.Name)
	io.WriteString(h, sc.Type)
	io.WriteString(h, sc.Command)
	io.WriteString(h, strings.Join(sc.Args, ""))
	io.WriteString(h, sc.Path)
	io.WriteString(h, sc.Protocol)
	io.WriteString(h, sc.PortLabel)
	io.WriteString(h, sc.Interval.String())
	io.WriteString(h, sc.Timeout.String())
	io.WriteString(h, sc.Method)
	// Only include TLSSkipVerify if set to maintain ID stability with Nomad <0.6
	if sc.TLSSkipVerify {
		io.WriteString(h, "true")
	}

	// Since map iteration order isn't stable we need to write k/v pairs to
	// a slice and sort it before hashing.
	if len(sc.Header) > 0 {
		headers := make([]string, 0, len(sc.Header))
		for k, v := range sc.Header {
			headers = append(headers, k+strings.Join(v, ""))
		}
		sort.Strings(headers)
		io.WriteString(h, strings.Join(headers, ""))
	}

	// Only include AddressMode if set to maintain ID stability with Nomad <0.7.1
	if len(sc.AddressMode) > 0 {
		io.WriteString(h, sc.AddressMode)
	}

	// Only include GRPC if set to maintain ID stability with Nomad <0.8.4
	if sc.GRPCService != "" {
		io.WriteString(h, sc.GRPCService)
	}
	if sc.GRPCUseTLS {
		io.WriteString(h, "true")
	}

	return fmt.Sprintf("%x", h.Sum(nil))
}

const (
	AddressModeAuto   = "auto"
	AddressModeHost   = "host"
	AddressModeDriver = "driver"
)

// Service represents a Consul service definition in Nomad
type Service struct {
	// Name of the service registered with Consul. Consul defaults the
	// Name to ServiceID if not specified.  The Name if specified is used
	// as one of the seed values when generating a Consul ServiceID.
	Name string

	// PortLabel is either the numeric port number or the `host:port`.
	// To specify the port number using the host's Consul Advertise
	// address, specify an empty host in the PortLabel (e.g. `:port`).
	PortLabel string

	// AddressMode specifies whether or not to use the host ip:port for
	// this service.
	AddressMode string

	Tags       []string        // List of tags for the service
	CanaryTags []string        // List of tags for the service when it is a canary
	Checks     []*ServiceCheck // List of checks associated with the service
}

func (s *Service) Copy() *Service {
	if s == nil {
		return nil
	}
	ns := new(Service)
	*ns = *s
	ns.Tags = helper.CopySliceString(ns.Tags)
	ns.CanaryTags = helper.CopySliceString(ns.CanaryTags)

	if s.Checks != nil {
		checks := make([]*ServiceCheck, len(ns.Checks))
		for i, c := range ns.Checks {
			checks[i] = c.Copy()
		}
		ns.Checks = checks
	}

	return ns
}

// Canonicalize interpolates values of Job, Task Group and Task in the Service
// Name. This also generates check names, service id and check ids.
func (s *Service) Canonicalize(job string, taskGroup string, task string) {
	// Ensure empty lists are treated as null to avoid scheduler issues when
	// using DeepEquals
	if len(s.Tags) == 0 {
		s.Tags = nil
	}
	if len(s.CanaryTags) == 0 {
		s.CanaryTags = nil
	}
	if len(s.Checks) == 0 {
		s.Checks = nil
	}

	s.Name = args.ReplaceEnv(s.Name, map[string]string{
		"JOB":       job,
		"TASKGROUP": taskGroup,
		"TASK":      task,
		"BASE":      fmt.Sprintf("%s-%s-%s", job, taskGroup, task),
	},
	)

	for _, check := range s.Checks {
		check.Canonicalize(s.Name)
	}
}

// Validate checks if the Check definition is valid
func (s *Service) Validate() error {
	var mErr multierror.Error

	// Ensure the service name is valid per the below RFCs but make an exception
	// for our interpolation syntax by first stripping any environment variables from the name

	serviceNameStripped := args.ReplaceEnvWithPlaceHolder(s.Name, "ENV-VAR")

	if err := s.ValidateName(serviceNameStripped); err != nil {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("service name must be valid per RFC 1123 and can contain only alphanumeric characters or dashes: %q", s.Name))
	}

	switch s.AddressMode {
	case "", AddressModeAuto, AddressModeHost, AddressModeDriver:
		// OK
	default:
		mErr.Errors = append(mErr.Errors, fmt.Errorf("service address_mode must be %q, %q, or %q; not %q", AddressModeAuto, AddressModeHost, AddressModeDriver, s.AddressMode))
	}

	for _, c := range s.Checks {
		if s.PortLabel == "" && c.PortLabel == "" && c.RequiresPort() {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("check %s invalid: check requires a port but neither check nor service %+q have a port", c.Name, s.Name))
			continue
		}

		if err := c.validate(); err != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("check %s invalid: %v", c.Name, err))
		}
	}

	return mErr.ErrorOrNil()
}

// ValidateName checks if the services Name is valid and should be called after
// the name has been interpolated
func (s *Service) ValidateName(name string) error {
	// Ensure the service name is valid per RFC-952 §1
	// (https://tools.ietf.org/html/rfc952), RFC-1123 §2.1
	// (https://tools.ietf.org/html/rfc1123), and RFC-2782
	// (https://tools.ietf.org/html/rfc2782).
	re := regexp.MustCompile(`^(?i:[a-z0-9]|[a-z0-9][a-z0-9\-]{0,61}[a-z0-9])$`)
	if !re.MatchString(name) {
		return fmt.Errorf("service name must be valid per RFC 1123 and can contain only alphanumeric characters or dashes and must be no longer than 63 characters: %q", name)
	}
	return nil
}

// Hash returns a base32 encoded hash of a Service's contents excluding checks
// as they're hashed independently.
func (s *Service) Hash(allocID, taskName string, canary bool) string {
	h := sha1.New()
	io.WriteString(h, allocID)
	io.WriteString(h, taskName)
	io.WriteString(h, s.Name)
	io.WriteString(h, s.PortLabel)
	io.WriteString(h, s.AddressMode)
	for _, tag := range s.Tags {
		io.WriteString(h, tag)
	}
	for _, tag := range s.CanaryTags {
		io.WriteString(h, tag)
	}

	// Vary ID on whether or not CanaryTags will be used
	if canary {
		h.Write([]byte("Canary"))
	}

	// Base32 is used for encoding the hash as sha1 hashes can always be
	// encoded without padding, only 4 bytes larger than base64, and saves
	// 8 bytes vs hex. Since these hashes are used in Consul URLs it's nice
	// to have a reasonably compact URL-safe representation.
	return b32.EncodeToString(h.Sum(nil))
}

const (
	// DefaultKillTimeout is the default timeout between signaling a task it
	// will be killed and killing it.
	DefaultKillTimeout = 5 * time.Second
)

// LogConfig provides configuration for log rotation
type LogConfig struct {
	MaxFiles      int
	MaxFileSizeMB int
}

// DefaultLogConfig returns the default LogConfig values.
func DefaultLogConfig() *LogConfig {
	return &LogConfig{
		MaxFiles:      10,
		MaxFileSizeMB: 10,
	}
}

// Validate returns an error if the log config specified are less than
// the minimum allowed.
func (l *LogConfig) Validate() error {
	var mErr multierror.Error
	if l.MaxFiles < 1 {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("minimum number of files is 1; got %d", l.MaxFiles))
	}
	if l.MaxFileSizeMB < 1 {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("minimum file size is 1MB; got %d", l.MaxFileSizeMB))
	}
	return mErr.ErrorOrNil()
}

// Task is a single process typically that is executed as part of a task group.
type Task struct {
	// Name of the task
	Name string

	// Driver is used to control which driver is used
	Driver string

	// User is used to determine which user will run the task. It defaults to
	// the same user the Nomad client is being run as.
	User string

	// Config is provided to the driver to initialize
	Config map[string]interface{}

	// Map of environment variables to be used by the driver
	Env map[string]string

	// List of service definitions exposed by the Task
	Services []*Service

	// Vault is used to define the set of Vault policies that this task should
	// have access to.
	Vault *Vault

	// Templates are the set of templates to be rendered for the task.
	Templates []*Template

	// Constraints can be specified at a task level and apply only to
	// the particular task.
	Constraints []*Constraint

	// Affinities can be specified at the task level to express
	// scheduling preferences
	Affinities []*Affinity

	// Resources is the resources needed by this task
	Resources *Resources

	// DispatchPayload configures how the task retrieves its input from a dispatch
	DispatchPayload *DispatchPayloadConfig

	// Meta is used to associate arbitrary metadata with this
	// task. This is opaque to Nomad.
	Meta map[string]string

	// KillTimeout is the time between signaling a task that it will be
	// killed and killing it.
	KillTimeout time.Duration

	// LogConfig provides configuration for log rotation
	LogConfig *LogConfig

	// Artifacts is a list of artifacts to download and extract before running
	// the task.
	Artifacts []*TaskArtifact

	// Leader marks the task as the leader within the group. When the leader
	// task exits, other tasks will be gracefully terminated.
	Leader bool

	// ShutdownDelay is the duration of the delay between deregistering a
	// task from Consul and sending it a signal to shutdown. See #2441
	ShutdownDelay time.Duration

	// The kill signal to use for the task. This is an optional specification,

	// KillSignal is the kill signal to use for the task. This is an optional
	// specification and defaults to SIGINT
	KillSignal string
}

func (t *Task) Copy() *Task {
	if t == nil {
		return nil
	}
	nt := new(Task)
	*nt = *t
	nt.Env = helper.CopyMapStringString(nt.Env)

	if t.Services != nil {
		services := make([]*Service, len(nt.Services))
		for i, s := range nt.Services {
			services[i] = s.Copy()
		}
		nt.Services = services
	}

	nt.Constraints = CopySliceConstraints(nt.Constraints)
	nt.Affinities = CopySliceAffinities(nt.Affinities)

	nt.Vault = nt.Vault.Copy()
	nt.Resources = nt.Resources.Copy()
	nt.Meta = helper.CopyMapStringString(nt.Meta)
	nt.DispatchPayload = nt.DispatchPayload.Copy()

	if t.Artifacts != nil {
		artifacts := make([]*TaskArtifact, 0, len(t.Artifacts))
		for _, a := range nt.Artifacts {
			artifacts = append(artifacts, a.Copy())
		}
		nt.Artifacts = artifacts
	}

	if i, err := copystructure.Copy(nt.Config); err != nil {
		panic(err.Error())
	} else {
		nt.Config = i.(map[string]interface{})
	}

	if t.Templates != nil {
		templates := make([]*Template, len(t.Templates))
		for i, tmpl := range nt.Templates {
			templates[i] = tmpl.Copy()
		}
		nt.Templates = templates
	}

	return nt
}

// Canonicalize canonicalizes fields in the task.
func (t *Task) Canonicalize(job *Job, tg *TaskGroup) {
	// Ensure that an empty and nil map are treated the same to avoid scheduling
	// problems since we use reflect DeepEquals.
	if len(t.Meta) == 0 {
		t.Meta = nil
	}
	if len(t.Config) == 0 {
		t.Config = nil
	}
	if len(t.Env) == 0 {
		t.Env = nil
	}

	for _, service := range t.Services {
		service.Canonicalize(job.Name, tg.Name, t.Name)
	}

	// If Resources are nil initialize them to defaults, otherwise canonicalize
	if t.Resources == nil {
		t.Resources = DefaultResources()
	} else {
		t.Resources.Canonicalize()
	}

	// Set the default timeout if it is not specified.
	if t.KillTimeout == 0 {
		t.KillTimeout = DefaultKillTimeout
	}

	if t.Vault != nil {
		t.Vault.Canonicalize()
	}

	for _, template := range t.Templates {
		template.Canonicalize()
	}
}

func (t *Task) GoString() string {
	return fmt.Sprintf("*%#v", *t)
}

// Validate is used to sanity check a task
func (t *Task) Validate(ephemeralDisk *EphemeralDisk, jobType string) error {
	var mErr multierror.Error
	if t.Name == "" {
		mErr.Errors = append(mErr.Errors, errors.New("Missing task name"))
	}
	if strings.ContainsAny(t.Name, `/\`) {
		// We enforce this so that when creating the directory on disk it will
		// not have any slashes.
		mErr.Errors = append(mErr.Errors, errors.New("Task name cannot include slashes"))
	}
	if t.Driver == "" {
		mErr.Errors = append(mErr.Errors, errors.New("Missing task driver"))
	}
	if t.KillTimeout < 0 {
		mErr.Errors = append(mErr.Errors, errors.New("KillTimeout must be a positive value"))
	}
	if t.ShutdownDelay < 0 {
		mErr.Errors = append(mErr.Errors, errors.New("ShutdownDelay must be a positive value"))
	}

	// Validate the resources.
	if t.Resources == nil {
		mErr.Errors = append(mErr.Errors, errors.New("Missing task resources"))
	} else if err := t.Resources.Validate(); err != nil {
		mErr.Errors = append(mErr.Errors, err)
	}

	// Validate the log config
	if t.LogConfig == nil {
		mErr.Errors = append(mErr.Errors, errors.New("Missing Log Config"))
	} else if err := t.LogConfig.Validate(); err != nil {
		mErr.Errors = append(mErr.Errors, err)
	}

	for idx, constr := range t.Constraints {
		if err := constr.Validate(); err != nil {
			outer := fmt.Errorf("Constraint %d validation failed: %s", idx+1, err)
			mErr.Errors = append(mErr.Errors, outer)
		}

		switch constr.Operand {
		case ConstraintDistinctHosts, ConstraintDistinctProperty:
			outer := fmt.Errorf("Constraint %d has disallowed Operand at task level: %s", idx+1, constr.Operand)
			mErr.Errors = append(mErr.Errors, outer)
		}
	}

	if jobType == JobTypeSystem {
		if t.Affinities != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("System jobs may not have an affinity stanza"))
		}
	} else {
		for idx, affinity := range t.Affinities {
			if err := affinity.Validate(); err != nil {
				outer := fmt.Errorf("Affinity %d validation failed: %s", idx+1, err)
				mErr.Errors = append(mErr.Errors, outer)
			}
		}
	}

	// Validate Services
	if err := validateServices(t); err != nil {
		mErr.Errors = append(mErr.Errors, err)
	}

	if t.LogConfig != nil && ephemeralDisk != nil {
		logUsage := (t.LogConfig.MaxFiles * t.LogConfig.MaxFileSizeMB)
		if ephemeralDisk.SizeMB <= logUsage {
			mErr.Errors = append(mErr.Errors,
				fmt.Errorf("log storage (%d MB) must be less than requested disk capacity (%d MB)",
					logUsage, ephemeralDisk.SizeMB))
		}
	}

	for idx, artifact := range t.Artifacts {
		if err := artifact.Validate(); err != nil {
			outer := fmt.Errorf("Artifact %d validation failed: %v", idx+1, err)
			mErr.Errors = append(mErr.Errors, outer)
		}
	}

	if t.Vault != nil {
		if err := t.Vault.Validate(); err != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Vault validation failed: %v", err))
		}
	}

	destinations := make(map[string]int, len(t.Templates))
	for idx, tmpl := range t.Templates {
		if err := tmpl.Validate(); err != nil {
			outer := fmt.Errorf("Template %d validation failed: %s", idx+1, err)
			mErr.Errors = append(mErr.Errors, outer)
		}

		if other, ok := destinations[tmpl.DestPath]; ok {
			outer := fmt.Errorf("Template %d has same destination as %d", idx+1, other)
			mErr.Errors = append(mErr.Errors, outer)
		} else {
			destinations[tmpl.DestPath] = idx + 1
		}
	}

	// Validate the dispatch payload block if there
	if t.DispatchPayload != nil {
		if err := t.DispatchPayload.Validate(); err != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Dispatch Payload validation failed: %v", err))
		}
	}

	return mErr.ErrorOrNil()
}

// validateServices takes a task and validates the services within it are valid
// and reference ports that exist.
func validateServices(t *Task) error {
	var mErr multierror.Error

	// Ensure that services don't ask for nonexistent ports and their names are
	// unique.
	servicePorts := make(map[string]map[string]struct{})
	addServicePort := func(label, service string) {
		if _, ok := servicePorts[label]; !ok {
			servicePorts[label] = map[string]struct{}{}
		}
		servicePorts[label][service] = struct{}{}
	}
	knownServices := make(map[string]struct{})
	for i, service := range t.Services {
		if err := service.Validate(); err != nil {
			outer := fmt.Errorf("service[%d] %+q validation failed: %s", i, service.Name, err)
			mErr.Errors = append(mErr.Errors, outer)
		}

		// Ensure that services with the same name are not being registered for
		// the same port
		if _, ok := knownServices[service.Name+service.PortLabel]; ok {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("service %q is duplicate", service.Name))
		}
		knownServices[service.Name+service.PortLabel] = struct{}{}

		if service.PortLabel != "" {
			if service.AddressMode == "driver" {
				// Numeric port labels are valid for address_mode=driver
				_, err := strconv.Atoi(service.PortLabel)
				if err != nil {
					// Not a numeric port label, add it to list to check
					addServicePort(service.PortLabel, service.Name)
				}
			} else {
				addServicePort(service.PortLabel, service.Name)
			}
		}

		// Ensure that check names are unique and have valid ports
		knownChecks := make(map[string]struct{})
		for _, check := range service.Checks {
			if _, ok := knownChecks[check.Name]; ok {
				mErr.Errors = append(mErr.Errors, fmt.Errorf("check %q is duplicate", check.Name))
			}
			knownChecks[check.Name] = struct{}{}

			if !check.RequiresPort() {
				// No need to continue validating check if it doesn't need a port
				continue
			}

			effectivePort := check.PortLabel
			if effectivePort == "" {
				// Inherits from service
				effectivePort = service.PortLabel
			}

			if effectivePort == "" {
				mErr.Errors = append(mErr.Errors, fmt.Errorf("check %q is missing a port", check.Name))
				continue
			}

			isNumeric := false
			portNumber, err := strconv.Atoi(effectivePort)
			if err == nil {
				isNumeric = true
			}

			// Numeric ports are fine for address_mode = "driver"
			if check.AddressMode == "driver" && isNumeric {
				if portNumber <= 0 {
					mErr.Errors = append(mErr.Errors, fmt.Errorf("check %q has invalid numeric port %d", check.Name, portNumber))
				}
				continue
			}

			if isNumeric {
				mErr.Errors = append(mErr.Errors, fmt.Errorf(`check %q cannot use a numeric port %d without setting address_mode="driver"`, check.Name, portNumber))
				continue
			}

			// PortLabel must exist, report errors by its parent service
			addServicePort(effectivePort, service.Name)
		}
	}

	// Get the set of port labels.
	portLabels := make(map[string]struct{})
	if t.Resources != nil {
		for _, network := range t.Resources.Networks {
			ports := network.PortLabels()
			for portLabel := range ports {
				portLabels[portLabel] = struct{}{}
			}
		}
	}

	// Iterate over a sorted list of keys to make error listings stable
	keys := make([]string, 0, len(servicePorts))
	for p := range servicePorts {
		keys = append(keys, p)
	}
	sort.Strings(keys)

	// Ensure all ports referenced in services exist.
	for _, servicePort := range keys {
		services := servicePorts[servicePort]
		_, ok := portLabels[servicePort]
		if !ok {
			names := make([]string, 0, len(services))
			for name := range services {
				names = append(names, name)
			}

			// Keep order deterministic
			sort.Strings(names)
			joined := strings.Join(names, ", ")
			err := fmt.Errorf("port label %q referenced by services %v does not exist", servicePort, joined)
			mErr.Errors = append(mErr.Errors, err)
		}
	}

	// Ensure address mode is valid
	return mErr.ErrorOrNil()
}

func (t *Task) Warnings() error {
	var mErr multierror.Error

	// Validate the resources
	if t.Resources != nil && t.Resources.IOPS != 0 {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("IOPS has been deprecated as of Nomad 0.9.0. Please remove IOPS from resource stanza."))
	}

	return mErr.ErrorOrNil()
}

const (
	// TemplateChangeModeNoop marks that no action should be taken if the
	// template is re-rendered
	TemplateChangeModeNoop = "noop"

	// TemplateChangeModeSignal marks that the task should be signaled if the
	// template is re-rendered
	TemplateChangeModeSignal = "signal"

	// TemplateChangeModeRestart marks that the task should be restarted if the
	// template is re-rendered
	TemplateChangeModeRestart = "restart"
)

var (
	// TemplateChangeModeInvalidError is the error for when an invalid change
	// mode is given
	TemplateChangeModeInvalidError = errors.New("Invalid change mode. Must be one of the following: noop, signal, restart")
)

// Template represents a template configuration to be rendered for a given task
type Template struct {
	// SourcePath is the path to the template to be rendered
	SourcePath string

	// DestPath is the path to where the template should be rendered
	DestPath string

	// EmbeddedTmpl store the raw template. This is useful for smaller templates
	// where they are embedded in the job file rather than sent as an artifact
	EmbeddedTmpl string

	// ChangeMode indicates what should be done if the template is re-rendered
	ChangeMode string

	// ChangeSignal is the signal that should be sent if the change mode
	// requires it.
	ChangeSignal string

	// Splay is used to avoid coordinated restarts of processes by applying a
	// random wait between 0 and the given splay value before signalling the
	// application of a change
	Splay time.Duration

	// Perms is the permission the file should be written out with.
	Perms string

	// LeftDelim and RightDelim are optional configurations to control what
	// delimiter is utilized when parsing the template.
	LeftDelim  string
	RightDelim string

	// Envvars enables exposing the template as environment variables
	// instead of as a file. The template must be of the form:
	//
	//	VAR_NAME_1={{ key service/my-key }}
	//	VAR_NAME_2=raw string and {{ env "attr.kernel.name" }}
	//
	// Lines will be split on the initial "=" with the first part being the
	// key name and the second part the value.
	// Empty lines and lines starting with # will be ignored, but to avoid
	// escaping issues #s within lines will not be treated as comments.
	Envvars bool

	// VaultGrace is the grace duration between lease renewal and reacquiring a
	// secret. If the lease of a secret is less than the grace, a new secret is
	// acquired.
	VaultGrace time.Duration
}

// DefaultTemplate returns a default template.
func DefaultTemplate() *Template {
	return &Template{
		ChangeMode: TemplateChangeModeRestart,
		Splay:      5 * time.Second,
		Perms:      "0644",
	}
}

func (t *Template) Copy() *Template {
	if t == nil {
		return nil
	}
	copy := new(Template)
	*copy = *t
	return copy
}

func (t *Template) Canonicalize() {
	if t.ChangeSignal != "" {
		t.ChangeSignal = strings.ToUpper(t.ChangeSignal)
	}
}

func (t *Template) Validate() error {
	var mErr multierror.Error

	// Verify we have something to render
	if t.SourcePath == "" && t.EmbeddedTmpl == "" {
		multierror.Append(&mErr, fmt.Errorf("Must specify a source path or have an embedded template"))
	}

	// Verify we can render somewhere
	if t.DestPath == "" {
		multierror.Append(&mErr, fmt.Errorf("Must specify a destination for the template"))
	}

	// Verify the destination doesn't escape
	escaped, err := PathEscapesAllocDir("task", t.DestPath)
	if err != nil {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("invalid destination path: %v", err))
	} else if escaped {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("destination escapes allocation directory"))
	}

	// Verify a proper change mode
	switch t.ChangeMode {
	case TemplateChangeModeNoop, TemplateChangeModeRestart:
	case TemplateChangeModeSignal:
		if t.ChangeSignal == "" {
			multierror.Append(&mErr, fmt.Errorf("Must specify signal value when change mode is signal"))
		}
		if t.Envvars {
			multierror.Append(&mErr, fmt.Errorf("cannot use signals with env var templates"))
		}
	default:
		multierror.Append(&mErr, TemplateChangeModeInvalidError)
	}

	// Verify the splay is positive
	if t.Splay < 0 {
		multierror.Append(&mErr, fmt.Errorf("Must specify positive splay value"))
	}

	// Verify the permissions
	if t.Perms != "" {
		if _, err := strconv.ParseUint(t.Perms, 8, 12); err != nil {
			multierror.Append(&mErr, fmt.Errorf("Failed to parse %q as octal: %v", t.Perms, err))
		}
	}

	if t.VaultGrace.Nanoseconds() < 0 {
		multierror.Append(&mErr, fmt.Errorf("Vault grace must be greater than zero: %v < 0", t.VaultGrace))
	}

	return mErr.ErrorOrNil()
}

// Set of possible states for a task.
const (
	TaskStatePending = "pending" // The task is waiting to be run.
	TaskStateRunning = "running" // The task is currently running.
	TaskStateDead    = "dead"    // Terminal state of task.
)

// TaskState tracks the current state of a task and events that caused state
// transitions.
type TaskState struct {
	// The current state of the task.
	State string

	// Failed marks a task as having failed
	Failed bool

	// Restarts is the number of times the task has restarted
	Restarts uint64

	// LastRestart is the time the task last restarted. It is updated each time the
	// task restarts
	LastRestart time.Time

	// StartedAt is the time the task is started. It is updated each time the
	// task starts
	StartedAt time.Time

	// FinishedAt is the time at which the task transitioned to dead and will
	// not be started again.
	FinishedAt time.Time

	// Series of task events that transition the state of the task.
	Events []*TaskEvent
}

// NewTaskState returns a TaskState initialized in the Pending state.
func NewTaskState() *TaskState {
	return &TaskState{
		State: TaskStatePending,
	}
}

// Canonicalize ensures the TaskState has a State set. It should default to
// Pending.
func (ts *TaskState) Canonicalize() {
	if ts.State == "" {
		ts.State = TaskStatePending
	}
}

func (ts *TaskState) Copy() *TaskState {
	if ts == nil {
		return nil
	}
	copy := new(TaskState)
	*copy = *ts

	if ts.Events != nil {
		copy.Events = make([]*TaskEvent, len(ts.Events))
		for i, e := range ts.Events {
			copy.Events[i] = e.Copy()
		}
	}
	return copy
}

// Successful returns whether a task finished successfully. This doesn't really
// have meaning on a non-batch allocation because a service and system
// allocation should not finish.
func (ts *TaskState) Successful() bool {
	return ts.State == TaskStateDead && !ts.Failed
}

const (
	// TaskSetupFailure indicates that the task could not be started due to a
	// a setup failure.
	TaskSetupFailure = "Setup Failure"

	// TaskDriveFailure indicates that the task could not be started due to a
	// failure in the driver.
	TaskDriverFailure = "Driver Failure"

	// TaskReceived signals that the task has been pulled by the client at the
	// given timestamp.
	TaskReceived = "Received"

	// TaskFailedValidation indicates the task was invalid and as such was not
	// run.
	TaskFailedValidation = "Failed Validation"

	// TaskStarted signals that the task was started and its timestamp can be
	// used to determine the running length of the task.
	TaskStarted = "Started"

	// TaskTerminated indicates that the task was started and exited.
	TaskTerminated = "Terminated"

	// TaskKilling indicates a kill signal has been sent to the task.
	TaskKilling = "Killing"

	// TaskKilled indicates a user has killed the task.
	TaskKilled = "Killed"

	// TaskRestarting indicates that task terminated and is being restarted.
	TaskRestarting = "Restarting"

	// TaskNotRestarting indicates that the task has failed and is not being
	// restarted because it has exceeded its restart policy.
	TaskNotRestarting = "Not Restarting"

	// TaskRestartSignal indicates that the task has been signalled to be
	// restarted
	TaskRestartSignal = "Restart Signaled"

	// TaskSignaling indicates that the task is being signalled.
	TaskSignaling = "Signaling"

	// TaskDownloadingArtifacts means the task is downloading the artifacts
	// specified in the task.
	TaskDownloadingArtifacts = "Downloading Artifacts"

	// TaskArtifactDownloadFailed indicates that downloading the artifacts
	// failed.
	TaskArtifactDownloadFailed = "Failed Artifact Download"

	// TaskBuildingTaskDir indicates that the task directory/chroot is being
	// built.
	TaskBuildingTaskDir = "Building Task Directory"

	// TaskSetup indicates the task runner is setting up the task environment
	TaskSetup = "Task Setup"

	// TaskDiskExceeded indicates that one of the tasks in a taskgroup has
	// exceeded the requested disk resources.
	TaskDiskExceeded = "Disk Resources Exceeded"

	// TaskSiblingFailed indicates that a sibling task in the task group has
	// failed.
	TaskSiblingFailed = "Sibling Task Failed"

	// TaskDriverMessage is an informational event message emitted by
	// drivers such as when they're performing a long running action like
	// downloading an image.
	TaskDriverMessage = "Driver"

	// TaskLeaderDead indicates that the leader task within the has finished.
	TaskLeaderDead = "Leader Task Dead"

	// TaskHookFailed indicates that one of the hooks for a task failed.
	TaskHookFailed = "Task hook failed"
)

// TaskEvent is an event that effects the state of a task and contains meta-data
// appropriate to the events type.
type TaskEvent struct {
	Type string
	Time int64 // Unix Nanosecond timestamp

	Message string // A possible message explaining the termination of the task.

	// DisplayMessage is a human friendly message about the event
	DisplayMessage string

	// Details is a map with annotated info about the event
	Details map[string]string

	// DEPRECATION NOTICE: The following fields are deprecated and will be removed
	// in a future release. Field values are available in the Details map.

	// FailsTask marks whether this event fails the task.
	// Deprecated, use Details["fails_task"] to access this.
	FailsTask bool

	// Restart fields.
	// Deprecated, use Details["restart_reason"] to access this.
	RestartReason string

	// Setup Failure fields.
	// Deprecated, use Details["setup_error"] to access this.
	SetupError string

	// Driver Failure fields.
	// Deprecated, use Details["driver_error"] to access this.
	DriverError string // A driver error occurred while starting the task.

	// Task Terminated Fields.

	// Deprecated, use Details["exit_code"] to access this.
	ExitCode int // The exit code of the task.

	// Deprecated, use Details["signal"] to access this.
	Signal int // The signal that terminated the task.

	// Killing fields
	// Deprecated, use Details["kill_timeout"] to access this.
	KillTimeout time.Duration

	// Task Killed Fields.
	// Deprecated, use Details["kill_error"] to access this.
	KillError string // Error killing the task.

	// KillReason is the reason the task was killed
	// Deprecated, use Details["kill_reason"] to access this.
	KillReason string

	// TaskRestarting fields.
	// Deprecated, use Details["start_delay"] to access this.
	StartDelay int64 // The sleep period before restarting the task in unix nanoseconds.

	// Artifact Download fields
	// Deprecated, use Details["download_error"] to access this.
	DownloadError string // Error downloading artifacts

	// Validation fields
	// Deprecated, use Details["validation_error"] to access this.
	ValidationError string // Validation error

	// The maximum allowed task disk size.
	// Deprecated, use Details["disk_limit"] to access this.
	DiskLimit int64

	// Name of the sibling task that caused termination of the task that
	// the TaskEvent refers to.
	// Deprecated, use Details["failed_sibling"] to access this.
	FailedSibling string

	// VaultError is the error from token renewal
	// Deprecated, use Details["vault_renewal_error"] to access this.
	VaultError string

	// TaskSignalReason indicates the reason the task is being signalled.
	// Deprecated, use Details["task_signal_reason"] to access this.
	TaskSignalReason string

	// TaskSignal is the signal that was sent to the task
	// Deprecated, use Details["task_signal"] to access this.
	TaskSignal string

	// DriverMessage indicates a driver action being taken.
	// Deprecated, use Details["driver_message"] to access this.
	DriverMessage string

	// GenericSource is the source of a message.
	// Deprecated, is redundant with event type.
	GenericSource string
}

func (event *TaskEvent) PopulateEventDisplayMessage() {
	// Build up the description based on the event type.
	if event == nil { //TODO(preetha) needs investigation alloc_runner's Run method sends a nil event when sigterming nomad. Why?
		return
	}

	if event.DisplayMessage != "" {
		return
	}

	var desc string
	switch event.Type {
	case TaskSetup:
		desc = event.Message
	case TaskStarted:
		desc = "Task started by client"
	case TaskReceived:
		desc = "Task received by client"
	case TaskFailedValidation:
		if event.ValidationError != "" {
			desc = event.ValidationError
		} else {
			desc = "Validation of task failed"
		}
	case TaskSetupFailure:
		if event.SetupError != "" {
			desc = event.SetupError
		} else {
			desc = "Task setup failed"
		}
	case TaskDriverFailure:
		if event.DriverError != "" {
			desc = event.DriverError
		} else {
			desc = "Failed to start task"
		}
	case TaskDownloadingArtifacts:
		desc = "Client is downloading artifacts"
	case TaskArtifactDownloadFailed:
		if event.DownloadError != "" {
			desc = event.DownloadError
		} else {
			desc = "Failed to download artifacts"
		}
	case TaskKilling:
		if event.KillReason != "" {
			desc = event.KillReason
		} else if event.KillTimeout != 0 {
			desc = fmt.Sprintf("Sent interrupt. Waiting %v before force killing", event.KillTimeout)
		} else {
			desc = "Sent interrupt"
		}
	case TaskKilled:
		if event.KillError != "" {
			desc = event.KillError
		} else {
			desc = "Task successfully killed"
		}
	case TaskTerminated:
		var parts []string
		parts = append(parts, fmt.Sprintf("Exit Code: %d", event.ExitCode))

		if event.Signal != 0 {
			parts = append(parts, fmt.Sprintf("Signal: %d", event.Signal))
		}

		if event.Message != "" {
			parts = append(parts, fmt.Sprintf("Exit Message: %q", event.Message))
		}
		desc = strings.Join(parts, ", ")
	case TaskRestarting:
		in := fmt.Sprintf("Task restarting in %v", time.Duration(event.StartDelay))
		if event.RestartReason != "" && event.RestartReason != ReasonWithinPolicy {
			desc = fmt.Sprintf("%s - %s", event.RestartReason, in)
		} else {
			desc = in
		}
	case TaskNotRestarting:
		if event.RestartReason != "" {
			desc = event.RestartReason
		} else {
			desc = "Task exceeded restart policy"
		}
	case TaskSiblingFailed:
		if event.FailedSibling != "" {
			desc = fmt.Sprintf("Task's sibling %q failed", event.FailedSibling)
		} else {
			desc = "Task's sibling failed"
		}
	case TaskSignaling:
		sig := event.TaskSignal
		reason := event.TaskSignalReason

		if sig == "" && reason == "" {
			desc = "Task being sent a signal"
		} else if sig == "" {
			desc = reason
		} else if reason == "" {
			desc = fmt.Sprintf("Task being sent signal %v", sig)
		} else {
			desc = fmt.Sprintf("Task being sent signal %v: %v", sig, reason)
		}
	case TaskRestartSignal:
		if event.RestartReason != "" {
			desc = event.RestartReason
		} else {
			desc = "Task signaled to restart"
		}
	case TaskDriverMessage:
		desc = event.DriverMessage
	case TaskLeaderDead:
		desc = "Leader Task in Group dead"
	default:
		desc = event.Message
	}

	event.DisplayMessage = desc
}

func (te *TaskEvent) GoString() string {
	return fmt.Sprintf("%v - %v", te.Time, te.Type)
}

// SetDisplayMessage sets the display message of TaskEvent
func (te *TaskEvent) SetDisplayMessage(msg string) *TaskEvent {
	te.DisplayMessage = msg
	return te
}

// SetMessage sets the message of TaskEvent
func (te *TaskEvent) SetMessage(msg string) *TaskEvent {
	te.Message = msg
	te.Details["message"] = msg
	return te
}

func (te *TaskEvent) Copy() *TaskEvent {
	if te == nil {
		return nil
	}
	copy := new(TaskEvent)
	*copy = *te
	return copy
}

func NewTaskEvent(event string) *TaskEvent {
	return &TaskEvent{
		Type:    event,
		Time:    time.Now().UnixNano(),
		Details: make(map[string]string),
	}
}

// SetSetupError is used to store an error that occurred while setting up the
// task
func (e *TaskEvent) SetSetupError(err error) *TaskEvent {
	if err != nil {
		e.SetupError = err.Error()
		e.Details["setup_error"] = err.Error()
	}
	return e
}

func (e *TaskEvent) SetFailsTask() *TaskEvent {
	e.FailsTask = true
	e.Details["fails_task"] = "true"
	return e
}

func (e *TaskEvent) SetDriverError(err error) *TaskEvent {
	if err != nil {
		e.DriverError = err.Error()
		e.Details["driver_error"] = err.Error()
	}
	return e
}

func (e *TaskEvent) SetExitCode(c int) *TaskEvent {
	e.ExitCode = c
	e.Details["exit_code"] = fmt.Sprintf("%d", c)
	return e
}

func (e *TaskEvent) SetSignal(s int) *TaskEvent {
	e.Signal = s
	e.Details["signal"] = fmt.Sprintf("%d", s)
	return e
}

func (e *TaskEvent) SetExitMessage(err error) *TaskEvent {
	if err != nil {
		e.Message = err.Error()
		e.Details["exit_message"] = err.Error()
	}
	return e
}

func (e *TaskEvent) SetKillError(err error) *TaskEvent {
	if err != nil {
		e.KillError = err.Error()
		e.Details["kill_error"] = err.Error()
	}
	return e
}

func (e *TaskEvent) SetKillReason(r string) *TaskEvent {
	e.KillReason = r
	e.Details["kill_reason"] = r
	return e
}

func (e *TaskEvent) SetRestartDelay(delay time.Duration) *TaskEvent {
	e.StartDelay = int64(delay)
	e.Details["start_delay"] = fmt.Sprintf("%d", delay)
	return e
}

func (e *TaskEvent) SetRestartReason(reason string) *TaskEvent {
	e.RestartReason = reason
	e.Details["restart_reason"] = reason
	return e
}

func (e *TaskEvent) SetTaskSignalReason(r string) *TaskEvent {
	e.TaskSignalReason = r
	e.Details["task_signal_reason"] = r
	return e
}

func (e *TaskEvent) SetTaskSignal(s os.Signal) *TaskEvent {
	e.TaskSignal = s.String()
	e.Details["task_signal"] = s.String()
	return e
}

func (e *TaskEvent) SetDownloadError(err error) *TaskEvent {
	if err != nil {
		e.DownloadError = err.Error()
		e.Details["download_error"] = err.Error()
	}
	return e
}

func (e *TaskEvent) SetValidationError(err error) *TaskEvent {
	if err != nil {
		e.ValidationError = err.Error()
		e.Details["validation_error"] = err.Error()
	}
	return e
}

func (e *TaskEvent) SetKillTimeout(timeout time.Duration) *TaskEvent {
	e.KillTimeout = timeout
	e.Details["kill_timeout"] = timeout.String()
	return e
}

func (e *TaskEvent) SetDiskLimit(limit int64) *TaskEvent {
	e.DiskLimit = limit
	e.Details["disk_limit"] = fmt.Sprintf("%d", limit)
	return e
}

func (e *TaskEvent) SetFailedSibling(sibling string) *TaskEvent {
	e.FailedSibling = sibling
	e.Details["failed_sibling"] = sibling
	return e
}

func (e *TaskEvent) SetVaultRenewalError(err error) *TaskEvent {
	if err != nil {
		e.VaultError = err.Error()
		e.Details["vault_renewal_error"] = err.Error()
	}
	return e
}

func (e *TaskEvent) SetDriverMessage(m string) *TaskEvent {
	e.DriverMessage = m
	e.Details["driver_message"] = m
	return e
}

func (e *TaskEvent) SetOOMKilled(oom bool) *TaskEvent {
	e.Details["oom_killed"] = strconv.FormatBool(oom)
	return e
}

// TaskArtifact is an artifact to download before running the task.
type TaskArtifact struct {
	// GetterSource is the source to download an artifact using go-getter
	GetterSource string

	// GetterOptions are options to use when downloading the artifact using
	// go-getter.
	GetterOptions map[string]string

	// GetterMode is the go-getter.ClientMode for fetching resources.
	// Defaults to "any" but can be set to "file" or "dir".
	GetterMode string

	// RelativeDest is the download destination given relative to the task's
	// directory.
	RelativeDest string
}

func (ta *TaskArtifact) Copy() *TaskArtifact {
	if ta == nil {
		return nil
	}
	nta := new(TaskArtifact)
	*nta = *ta
	nta.GetterOptions = helper.CopyMapStringString(ta.GetterOptions)
	return nta
}

func (ta *TaskArtifact) GoString() string {
	return fmt.Sprintf("%+v", ta)
}

// Hash creates a unique identifier for a TaskArtifact as the same GetterSource
// may be specified multiple times with different destinations.
func (ta *TaskArtifact) Hash() string {
	hash, err := blake2b.New256(nil)
	if err != nil {
		panic(err)
	}

	hash.Write([]byte(ta.GetterSource))

	// Must iterate over keys in a consistent order
	keys := make([]string, 0, len(ta.GetterOptions))
	for k := range ta.GetterOptions {
		keys = append(keys, k)
	}
	sort.Strings(keys)
	for _, k := range keys {
		hash.Write([]byte(k))
		hash.Write([]byte(ta.GetterOptions[k]))
	}

	hash.Write([]byte(ta.GetterMode))
	hash.Write([]byte(ta.RelativeDest))
	return base64.RawStdEncoding.EncodeToString(hash.Sum(nil))
}

// PathEscapesAllocDir returns if the given path escapes the allocation
// directory. The prefix allows adding a prefix if the path will be joined, for
// example a "task/local" prefix may be provided if the path will be joined
// against that prefix.
func PathEscapesAllocDir(prefix, path string) (bool, error) {
	// Verify the destination doesn't escape the tasks directory
	alloc, err := filepath.Abs(filepath.Join("/", "alloc-dir/", "alloc-id/"))
	if err != nil {
		return false, err
	}
	abs, err := filepath.Abs(filepath.Join(alloc, prefix, path))
	if err != nil {
		return false, err
	}
	rel, err := filepath.Rel(alloc, abs)
	if err != nil {
		return false, err
	}

	return strings.HasPrefix(rel, ".."), nil
}

func (ta *TaskArtifact) Validate() error {
	// Verify the source
	var mErr multierror.Error
	if ta.GetterSource == "" {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("source must be specified"))
	}

	switch ta.GetterMode {
	case "":
		// Default to any
		ta.GetterMode = GetterModeAny
	case GetterModeAny, GetterModeFile, GetterModeDir:
		// Ok
	default:
		mErr.Errors = append(mErr.Errors, fmt.Errorf("invalid artifact mode %q; must be one of: %s, %s, %s",
			ta.GetterMode, GetterModeAny, GetterModeFile, GetterModeDir))
	}

	escaped, err := PathEscapesAllocDir("task", ta.RelativeDest)
	if err != nil {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("invalid destination path: %v", err))
	} else if escaped {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("destination escapes allocation directory"))
	}

	if err := ta.validateChecksum(); err != nil {
		mErr.Errors = append(mErr.Errors, err)
	}

	return mErr.ErrorOrNil()
}

func (ta *TaskArtifact) validateChecksum() error {
	check, ok := ta.GetterOptions["checksum"]
	if !ok {
		return nil
	}

	// Job struct validation occurs before interpolation resolution can be effective.
	// Skip checking if checksum contain variable reference, and artifacts fetching will
	// eventually fail, if checksum is indeed invalid.
	if args.ContainsEnv(check) {
		return nil
	}

	check = strings.TrimSpace(check)
	if check == "" {
		return fmt.Errorf("checksum value cannot be empty")
	}

	parts := strings.Split(check, ":")
	if l := len(parts); l != 2 {
		return fmt.Errorf(`checksum must be given as "type:value"; got %q`, check)
	}

	checksumVal := parts[1]
	checksumBytes, err := hex.DecodeString(checksumVal)
	if err != nil {
		return fmt.Errorf("invalid checksum: %v", err)
	}

	checksumType := parts[0]
	expectedLength := 0
	switch checksumType {
	case "md5":
		expectedLength = md5.Size
	case "sha1":
		expectedLength = sha1.Size
	case "sha256":
		expectedLength = sha256.Size
	case "sha512":
		expectedLength = sha512.Size
	default:
		return fmt.Errorf("unsupported checksum type: %s", checksumType)
	}

	if len(checksumBytes) != expectedLength {
		return fmt.Errorf("invalid %s checksum: %v", checksumType, checksumVal)
	}

	return nil
}

const (
	ConstraintDistinctProperty  = "distinct_property"
	ConstraintDistinctHosts     = "distinct_hosts"
	ConstraintRegex             = "regexp"
	ConstraintVersion           = "version"
	ConstraintSetContains       = "set_contains"
	ConstraintSetContainsAll    = "set_contains_all"
	ConstraintSetContainsAny    = "set_contains_any"
	ConstraintAttributeIsSet    = "is_set"
	ConstraintAttributeIsNotSet = "is_not_set"
)

// Constraints are used to restrict placement options.
type Constraint struct {
	LTarget string // Left-hand target
	RTarget string // Right-hand target
	Operand string // Constraint operand (<=, <, =, !=, >, >=), contains, near
	str     string // Memoized string
}

// Equal checks if two constraints are equal
func (c *Constraint) Equal(o *Constraint) bool {
	return c.LTarget == o.LTarget &&
		c.RTarget == o.RTarget &&
		c.Operand == o.Operand
}

func (c *Constraint) Copy() *Constraint {
	if c == nil {
		return nil
	}
	nc := new(Constraint)
	*nc = *c
	return nc
}

func (c *Constraint) String() string {
	if c.str != "" {
		return c.str
	}
	c.str = fmt.Sprintf("%s %s %s", c.LTarget, c.Operand, c.RTarget)
	return c.str
}

func (c *Constraint) Validate() error {
	var mErr multierror.Error
	if c.Operand == "" {
		mErr.Errors = append(mErr.Errors, errors.New("Missing constraint operand"))
	}

	// requireLtarget specifies whether the constraint requires an LTarget to be
	// provided.
	requireLtarget := true

	// Perform additional validation based on operand
	switch c.Operand {
	case ConstraintDistinctHosts:
		requireLtarget = false
	case ConstraintSetContainsAll, ConstraintSetContainsAny, ConstraintSetContains:
		if c.RTarget == "" {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Set contains constraint requires an RTarget"))
		}
	case ConstraintRegex:
		if _, err := regexp.Compile(c.RTarget); err != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Regular expression failed to compile: %v", err))
		}
	case ConstraintVersion:
		if _, err := version.NewConstraint(c.RTarget); err != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Version constraint is invalid: %v", err))
		}
	case ConstraintDistinctProperty:
		// If a count is set, make sure it is convertible to a uint64
		if c.RTarget != "" {
			count, err := strconv.ParseUint(c.RTarget, 10, 64)
			if err != nil {
				mErr.Errors = append(mErr.Errors, fmt.Errorf("Failed to convert RTarget %q to uint64: %v", c.RTarget, err))
			} else if count < 1 {
				mErr.Errors = append(mErr.Errors, fmt.Errorf("Distinct Property must have an allowed count of 1 or greater: %d < 1", count))
			}
		}
	case ConstraintAttributeIsSet, ConstraintAttributeIsNotSet:
		if c.RTarget != "" {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Operator %q does not support an RTarget", c.Operand))
		}
	case "=", "==", "is", "!=", "not", "<", "<=", ">", ">=":
		if c.RTarget == "" {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Operator %q requires an RTarget", c.Operand))
		}
	default:
		mErr.Errors = append(mErr.Errors, fmt.Errorf("Unknown constraint type %q", c.Operand))
	}

	// Ensure we have an LTarget for the constraints that need one
	if requireLtarget && c.LTarget == "" {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("No LTarget provided but is required by constraint"))
	}

	return mErr.ErrorOrNil()
}

// Affinity is used to score placement options based on a weight
type Affinity struct {
	LTarget string // Left-hand target
	RTarget string // Right-hand target
	Operand string // Affinity operand (<=, <, =, !=, >, >=), set_contains_all, set_contains_any
	Weight  int8   // Weight applied to nodes that match the affinity. Can be negative
	str     string // Memoized string
}

// Equal checks if two affinities are equal
func (a *Affinity) Equal(o *Affinity) bool {
	return a.LTarget == o.LTarget &&
		a.RTarget == o.RTarget &&
		a.Operand == o.Operand &&
		a.Weight == o.Weight
}

func (a *Affinity) Copy() *Affinity {
	if a == nil {
		return nil
	}
	na := new(Affinity)
	*na = *a
	return na
}

func (a *Affinity) String() string {
	if a.str != "" {
		return a.str
	}
	a.str = fmt.Sprintf("%s %s %s %v", a.LTarget, a.Operand, a.RTarget, a.Weight)
	return a.str
}

func (a *Affinity) Validate() error {
	var mErr multierror.Error
	if a.Operand == "" {
		mErr.Errors = append(mErr.Errors, errors.New("Missing affinity operand"))
	}

	// Perform additional validation based on operand
	switch a.Operand {
	case ConstraintSetContainsAll, ConstraintSetContainsAny, ConstraintSetContains:
		if a.RTarget == "" {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Set contains operators require an RTarget"))
		}
	case ConstraintRegex:
		if _, err := regexp.Compile(a.RTarget); err != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Regular expression failed to compile: %v", err))
		}
	case ConstraintVersion:
		if _, err := version.NewConstraint(a.RTarget); err != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Version affinity is invalid: %v", err))
		}
	case "=", "==", "is", "!=", "not", "<", "<=", ">", ">=":
		if a.RTarget == "" {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Operator %q requires an RTarget", a.Operand))
		}
	default:
		mErr.Errors = append(mErr.Errors, fmt.Errorf("Unknown affinity operator %q", a.Operand))
	}

	// Ensure we have an LTarget
	if a.LTarget == "" {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("No LTarget provided but is required"))
	}

	// Ensure that weight is between -100 and 100, and not zero
	if a.Weight == 0 {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("Affinity weight cannot be zero"))
	}

	if a.Weight > 100 || a.Weight < -100 {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("Affinity weight must be within the range [-100,100]"))
	}

	return mErr.ErrorOrNil()
}

// Spread is used to specify desired distribution of allocations according to weight
type Spread struct {
	// Attribute is the node attribute used as the spread criteria
	Attribute string

	// Weight is the relative weight of this spread, useful when there are multiple
	// spread and affinities
	Weight int8

	// SpreadTarget is used to describe desired percentages for each attribute value
	SpreadTarget []*SpreadTarget

	// Memoized string representation
	str string
}

func (s *Spread) Copy() *Spread {
	if s == nil {
		return nil
	}
	ns := new(Spread)
	*ns = *s

	ns.SpreadTarget = CopySliceSpreadTarget(s.SpreadTarget)
	return ns
}

func (s *Spread) String() string {
	if s.str != "" {
		return s.str
	}
	s.str = fmt.Sprintf("%s %s %v", s.Attribute, s.SpreadTarget, s.Weight)
	return s.str
}

func (s *Spread) Validate() error {
	var mErr multierror.Error
	if s.Attribute == "" {
		mErr.Errors = append(mErr.Errors, errors.New("Missing spread attribute"))
	}
	if s.Weight <= 0 || s.Weight > 100 {
		mErr.Errors = append(mErr.Errors, errors.New("Spread stanza must have a positive weight from 0 to 100"))
	}
	seen := make(map[string]struct{})
	sumPercent := uint32(0)

	for _, target := range s.SpreadTarget {
		// Make sure there are no duplicates
		_, ok := seen[target.Value]
		if !ok {
			seen[target.Value] = struct{}{}
		} else {
			mErr.Errors = append(mErr.Errors, errors.New(fmt.Sprintf("Spread target value %q already defined", target.Value)))
		}
		if target.Percent < 0 || target.Percent > 100 {
			mErr.Errors = append(mErr.Errors, errors.New(fmt.Sprintf("Spread target percentage for value %q must be between 0 and 100", target.Value)))
		}
		sumPercent += uint32(target.Percent)
	}
	if sumPercent > 100 {
		mErr.Errors = append(mErr.Errors, errors.New(fmt.Sprintf("Sum of spread target percentages must not be greater than 100%%; got %d%%", sumPercent)))
	}
	return mErr.ErrorOrNil()
}

// SpreadTarget is used to specify desired percentages for each attribute value
type SpreadTarget struct {
	// Value is a single attribute value, like "dc1"
	Value string

	// Percent is the desired percentage of allocs
	Percent uint8

	// Memoized string representation
	str string
}

func (s *SpreadTarget) Copy() *SpreadTarget {
	if s == nil {
		return nil
	}

	ns := new(SpreadTarget)
	*ns = *s
	return ns
}

func (s *SpreadTarget) String() string {
	if s.str != "" {
		return s.str
	}
	s.str = fmt.Sprintf("%q %v%%", s.Value, s.Percent)
	return s.str
}

// EphemeralDisk is an ephemeral disk object
type EphemeralDisk struct {
	// Sticky indicates whether the allocation is sticky to a node
	Sticky bool

	// SizeMB is the size of the local disk
	SizeMB int

	// Migrate determines if Nomad client should migrate the allocation dir for
	// sticky allocations
	Migrate bool
}

// DefaultEphemeralDisk returns a EphemeralDisk with default configurations
func DefaultEphemeralDisk() *EphemeralDisk {
	return &EphemeralDisk{
		SizeMB: 300,
	}
}

// Validate validates EphemeralDisk
func (d *EphemeralDisk) Validate() error {
	if d.SizeMB < 10 {
		return fmt.Errorf("minimum DiskMB value is 10; got %d", d.SizeMB)
	}
	return nil
}

// Copy copies the EphemeralDisk struct and returns a new one
func (d *EphemeralDisk) Copy() *EphemeralDisk {
	ld := new(EphemeralDisk)
	*ld = *d
	return ld
}

var (
	// VaultUnrecoverableError matches unrecoverable errors returned by a Vault
	// server
	VaultUnrecoverableError = regexp.MustCompile(`Code:\s+40(0|3|4)`)
)

const (
	// VaultChangeModeNoop takes no action when a new token is retrieved.
	VaultChangeModeNoop = "noop"

	// VaultChangeModeSignal signals the task when a new token is retrieved.
	VaultChangeModeSignal = "signal"

	// VaultChangeModeRestart restarts the task when a new token is retrieved.
	VaultChangeModeRestart = "restart"
)

// Vault stores the set of permissions a task needs access to from Vault.
type Vault struct {
	// Policies is the set of policies that the task needs access to
	Policies []string

	// Env marks whether the Vault Token should be exposed as an environment
	// variable
	Env bool

	// ChangeMode is used to configure the task's behavior when the Vault
	// token changes because the original token could not be renewed in time.
	ChangeMode string

	// ChangeSignal is the signal sent to the task when a new token is
	// retrieved. This is only valid when using the signal change mode.
	ChangeSignal string
}

func DefaultVaultBlock() *Vault {
	return &Vault{
		Env:        true,
		ChangeMode: VaultChangeModeRestart,
	}
}

// Copy returns a copy of this Vault block.
func (v *Vault) Copy() *Vault {
	if v == nil {
		return nil
	}

	nv := new(Vault)
	*nv = *v
	return nv
}

func (v *Vault) Canonicalize() {
	if v.ChangeSignal != "" {
		v.ChangeSignal = strings.ToUpper(v.ChangeSignal)
	}
}

// Validate returns if the Vault block is valid.
func (v *Vault) Validate() error {
	if v == nil {
		return nil
	}

	var mErr multierror.Error
	if len(v.Policies) == 0 {
		multierror.Append(&mErr, fmt.Errorf("Policy list cannot be empty"))
	}

	for _, p := range v.Policies {
		if p == "root" {
			multierror.Append(&mErr, fmt.Errorf("Can not specify \"root\" policy"))
		}
	}

	switch v.ChangeMode {
	case VaultChangeModeSignal:
		if v.ChangeSignal == "" {
			multierror.Append(&mErr, fmt.Errorf("Signal must be specified when using change mode %q", VaultChangeModeSignal))
		}
	case VaultChangeModeNoop, VaultChangeModeRestart:
	default:
		multierror.Append(&mErr, fmt.Errorf("Unknown change mode %q", v.ChangeMode))
	}

	return mErr.ErrorOrNil()
}

const (
	// DeploymentStatuses are the various states a deployment can be be in
	DeploymentStatusRunning    = "running"
	DeploymentStatusPaused     = "paused"
	DeploymentStatusFailed     = "failed"
	DeploymentStatusSuccessful = "successful"
	DeploymentStatusCancelled  = "cancelled"

	// DeploymentStatusDescriptions are the various descriptions of the states a
	// deployment can be in.
	DeploymentStatusDescriptionRunning               = "Deployment is running"
	DeploymentStatusDescriptionRunningNeedsPromotion = "Deployment is running but requires promotion"
	DeploymentStatusDescriptionPaused                = "Deployment is paused"
	DeploymentStatusDescriptionSuccessful            = "Deployment completed successfully"
	DeploymentStatusDescriptionStoppedJob            = "Cancelled because job is stopped"
	DeploymentStatusDescriptionNewerJob              = "Cancelled due to newer version of job"
	DeploymentStatusDescriptionFailedAllocations     = "Failed due to unhealthy allocations"
	DeploymentStatusDescriptionProgressDeadline      = "Failed due to progress deadline"
	DeploymentStatusDescriptionFailedByUser          = "Deployment marked as failed"
)

// DeploymentStatusDescriptionRollback is used to get the status description of
// a deployment when rolling back to an older job.
func DeploymentStatusDescriptionRollback(baseDescription string, jobVersion uint64) string {
	return fmt.Sprintf("%s - rolling back to job version %d", baseDescription, jobVersion)
}

// DeploymentStatusDescriptionRollbackNoop is used to get the status description of
// a deployment when rolling back is not possible because it has the same specification
func DeploymentStatusDescriptionRollbackNoop(baseDescription string, jobVersion uint64) string {
	return fmt.Sprintf("%s - not rolling back to stable job version %d as current job has same specification", baseDescription, jobVersion)
}

// DeploymentStatusDescriptionNoRollbackTarget is used to get the status description of
// a deployment when there is no target to rollback to but autorevert is desired.
func DeploymentStatusDescriptionNoRollbackTarget(baseDescription string) string {
	return fmt.Sprintf("%s - no stable job version to auto revert to", baseDescription)
}

// Deployment is the object that represents a job deployment which is used to
// transition a job between versions.
type Deployment struct {
	// ID is a generated UUID for the deployment
	ID string

	// Namespace is the namespace the deployment is created in
	Namespace string

	// JobID is the job the deployment is created for
	JobID string

	// JobVersion is the version of the job at which the deployment is tracking
	JobVersion uint64

	// JobModifyIndex is the ModifyIndex of the job which the deployment is
	// tracking.
	JobModifyIndex uint64

	// JobSpecModifyIndex is the JobModifyIndex of the job which the
	// deployment is tracking.
	JobSpecModifyIndex uint64

	// JobCreateIndex is the create index of the job which the deployment is
	// tracking. It is needed so that if the job gets stopped and reran we can
	// present the correct list of deployments for the job and not old ones.
	JobCreateIndex uint64

	// TaskGroups is the set of task groups effected by the deployment and their
	// current deployment status.
	TaskGroups map[string]*DeploymentState

	// The status of the deployment
	Status string

	// StatusDescription allows a human readable description of the deployment
	// status.
	StatusDescription string

	CreateIndex uint64
	ModifyIndex uint64
}

// NewDeployment creates a new deployment given the job.
func NewDeployment(job *Job) *Deployment {
	return &Deployment{
		ID:                 uuid.Generate(),
		Namespace:          job.Namespace,
		JobID:              job.ID,
		JobVersion:         job.Version,
		JobModifyIndex:     job.ModifyIndex,
		JobSpecModifyIndex: job.JobModifyIndex,
		JobCreateIndex:     job.CreateIndex,
		Status:             DeploymentStatusRunning,
		StatusDescription:  DeploymentStatusDescriptionRunning,
		TaskGroups:         make(map[string]*DeploymentState, len(job.TaskGroups)),
	}
}

func (d *Deployment) Copy() *Deployment {
	if d == nil {
		return nil
	}

	c := &Deployment{}
	*c = *d

	c.TaskGroups = nil
	if l := len(d.TaskGroups); d.TaskGroups != nil {
		c.TaskGroups = make(map[string]*DeploymentState, l)
		for tg, s := range d.TaskGroups {
			c.TaskGroups[tg] = s.Copy()
		}
	}

	return c
}

// Active returns whether the deployment is active or terminal.
func (d *Deployment) Active() bool {
	switch d.Status {
	case DeploymentStatusRunning, DeploymentStatusPaused:
		return true
	default:
		return false
	}
}

// GetID is a helper for getting the ID when the object may be nil
func (d *Deployment) GetID() string {
	if d == nil {
		return ""
	}
	return d.ID
}

// HasPlacedCanaries returns whether the deployment has placed canaries
func (d *Deployment) HasPlacedCanaries() bool {
	if d == nil || len(d.TaskGroups) == 0 {
		return false
	}
	for _, group := range d.TaskGroups {
		if len(group.PlacedCanaries) != 0 {
			return true
		}
	}
	return false
}

// RequiresPromotion returns whether the deployment requires promotion to
// continue
func (d *Deployment) RequiresPromotion() bool {
	if d == nil || len(d.TaskGroups) == 0 || d.Status != DeploymentStatusRunning {
		return false
	}
	for _, group := range d.TaskGroups {
		if group.DesiredCanaries > 0 && !group.Promoted {
			return true
		}
	}
	return false
}

func (d *Deployment) GoString() string {
	base := fmt.Sprintf("Deployment ID %q for job %q has status %q (%v):", d.ID, d.JobID, d.Status, d.StatusDescription)
	for group, state := range d.TaskGroups {
		base += fmt.Sprintf("\nTask Group %q has state:\n%#v", group, state)
	}
	return base
}

// DeploymentState tracks the state of a deployment for a given task group.
type DeploymentState struct {
	// AutoRevert marks whether the task group has indicated the job should be
	// reverted on failure
	AutoRevert bool

	// ProgressDeadline is the deadline by which an allocation must transition
	// to healthy before the deployment is considered failed.
	ProgressDeadline time.Duration

	// RequireProgressBy is the time by which an allocation must transition
	// to healthy before the deployment is considered failed.
	RequireProgressBy time.Time

	// Promoted marks whether the canaries have been promoted
	Promoted bool

	// PlacedCanaries is the set of placed canary allocations
	PlacedCanaries []string

	// DesiredCanaries is the number of canaries that should be created.
	DesiredCanaries int

	// DesiredTotal is the total number of allocations that should be created as
	// part of the deployment.
	DesiredTotal int

	// PlacedAllocs is the number of allocations that have been placed
	PlacedAllocs int

	// HealthyAllocs is the number of allocations that have been marked healthy.
	HealthyAllocs int

	// UnhealthyAllocs are allocations that have been marked as unhealthy.
	UnhealthyAllocs int
}

func (d *DeploymentState) GoString() string {
	base := fmt.Sprintf("\tDesired Total: %d", d.DesiredTotal)
	base += fmt.Sprintf("\n\tDesired Canaries: %d", d.DesiredCanaries)
	base += fmt.Sprintf("\n\tPlaced Canaries: %#v", d.PlacedCanaries)
	base += fmt.Sprintf("\n\tPromoted: %v", d.Promoted)
	base += fmt.Sprintf("\n\tPlaced: %d", d.PlacedAllocs)
	base += fmt.Sprintf("\n\tHealthy: %d", d.HealthyAllocs)
	base += fmt.Sprintf("\n\tUnhealthy: %d", d.UnhealthyAllocs)
	base += fmt.Sprintf("\n\tAutoRevert: %v", d.AutoRevert)
	return base
}

func (d *DeploymentState) Copy() *DeploymentState {
	c := &DeploymentState{}
	*c = *d
	c.PlacedCanaries = helper.CopySliceString(d.PlacedCanaries)
	return c
}

// DeploymentStatusUpdate is used to update the status of a given deployment
type DeploymentStatusUpdate struct {
	// DeploymentID is the ID of the deployment to update
	DeploymentID string

	// Status is the new status of the deployment.
	Status string

	// StatusDescription is the new status description of the deployment.
	StatusDescription string
}

// RescheduleTracker encapsulates previous reschedule events
type RescheduleTracker struct {
	Events []*RescheduleEvent
}

func (rt *RescheduleTracker) Copy() *RescheduleTracker {
	if rt == nil {
		return nil
	}
	nt := &RescheduleTracker{}
	*nt = *rt
	rescheduleEvents := make([]*RescheduleEvent, 0, len(rt.Events))
	for _, tracker := range rt.Events {
		rescheduleEvents = append(rescheduleEvents, tracker.Copy())
	}
	nt.Events = rescheduleEvents
	return nt
}

// RescheduleEvent is used to keep track of previous attempts at rescheduling an allocation
type RescheduleEvent struct {
	// RescheduleTime is the timestamp of a reschedule attempt
	RescheduleTime int64

	// PrevAllocID is the ID of the previous allocation being restarted
	PrevAllocID string

	// PrevNodeID is the node ID of the previous allocation
	PrevNodeID string

	// Delay is the reschedule delay associated with the attempt
	Delay time.Duration
}

func NewRescheduleEvent(rescheduleTime int64, prevAllocID string, prevNodeID string, delay time.Duration) *RescheduleEvent {
	return &RescheduleEvent{RescheduleTime: rescheduleTime,
		PrevAllocID: prevAllocID,
		PrevNodeID:  prevNodeID,
		Delay:       delay}
}

func (re *RescheduleEvent) Copy() *RescheduleEvent {
	if re == nil {
		return nil
	}
	copy := new(RescheduleEvent)
	*copy = *re
	return copy
}

// DesiredTransition is used to mark an allocation as having a desired state
// transition. This information can be used by the scheduler to make the
// correct decision.
type DesiredTransition struct {
	// Migrate is used to indicate that this allocation should be stopped and
	// migrated to another node.
	Migrate *bool

	// Reschedule is used to indicate that this allocation is eligible to be
	// rescheduled. Most allocations are automatically eligible for
	// rescheduling, so this field is only required when an allocation is not
	// automatically eligible. An example is an allocation that is part of a
	// deployment.
	Reschedule *bool

	// ForceReschedule is used to indicate that this allocation must be rescheduled.
	// This field is only used when operators want to force a placement even if
	// a failed allocation is not eligible to be rescheduled
	ForceReschedule *bool
}

// Merge merges the two desired transitions, preferring the values from the
// passed in object.
func (d *DesiredTransition) Merge(o *DesiredTransition) {
	if o.Migrate != nil {
		d.Migrate = o.Migrate
	}

	if o.Reschedule != nil {
		d.Reschedule = o.Reschedule
	}

	if o.ForceReschedule != nil {
		d.ForceReschedule = o.ForceReschedule
	}
}

// ShouldMigrate returns whether the transition object dictates a migration.
func (d *DesiredTransition) ShouldMigrate() bool {
	return d.Migrate != nil && *d.Migrate
}

// ShouldReschedule returns whether the transition object dictates a
// rescheduling.
func (d *DesiredTransition) ShouldReschedule() bool {
	return d.Reschedule != nil && *d.Reschedule
}

// ShouldForceReschedule returns whether the transition object dictates a
// forced rescheduling.
func (d *DesiredTransition) ShouldForceReschedule() bool {
	if d == nil {
		return false
	}
	return d.ForceReschedule != nil && *d.ForceReschedule
}

const (
	AllocDesiredStatusRun   = "run"   // Allocation should run
	AllocDesiredStatusStop  = "stop"  // Allocation should stop
	AllocDesiredStatusEvict = "evict" // Allocation should stop, and was evicted
)

const (
	AllocClientStatusPending  = "pending"
	AllocClientStatusRunning  = "running"
	AllocClientStatusComplete = "complete"
	AllocClientStatusFailed   = "failed"
	AllocClientStatusLost     = "lost"
)

// Allocation is used to allocate the placement of a task group to a node.
type Allocation struct {
	// ID of the allocation (UUID)
	ID string

	// Namespace is the namespace the allocation is created in
	Namespace string

	// ID of the evaluation that generated this allocation
	EvalID string

	// Name is a logical name of the allocation.
	Name string

	// NodeID is the node this is being placed on
	NodeID string

	// Job is the parent job of the task group being allocated.
	// This is copied at allocation time to avoid issues if the job
	// definition is updated.
	JobID string
	Job   *Job

	// TaskGroup is the name of the task group that should be run
	TaskGroup string

	// COMPAT(0.11): Remove in 0.11
	// Resources is the total set of resources allocated as part
	// of this allocation of the task group. Dynamic ports will be set by
	// the scheduler.
	Resources *Resources

	// COMPAT(0.11): Remove in 0.11
	// SharedResources are the resources that are shared by all the tasks in an
	// allocation
	SharedResources *Resources

	// COMPAT(0.11): Remove in 0.11
	// TaskResources is the set of resources allocated to each
	// task. These should sum to the total Resources. Dynamic ports will be
	// set by the scheduler.
	TaskResources map[string]*Resources

	// AllocatedResources is the total resources allocated for the task group.
	AllocatedResources *AllocatedResources

	// Metrics associated with this allocation
	Metrics *AllocMetric

	// Desired Status of the allocation on the client
	DesiredStatus string

	// DesiredStatusDescription is meant to provide more human useful information
	DesiredDescription string

	// DesiredTransition is used to indicate that a state transition
	// is desired for a given reason.
	DesiredTransition DesiredTransition

	// Status of the allocation on the client
	ClientStatus string

	// ClientStatusDescription is meant to provide more human useful information
	ClientDescription string

	// TaskStates stores the state of each task,
	TaskStates map[string]*TaskState

	// PreviousAllocation is the allocation that this allocation is replacing
	PreviousAllocation string

	// NextAllocation is the allocation that this allocation is being replaced by
	NextAllocation string

	// DeploymentID identifies an allocation as being created from a
	// particular deployment
	DeploymentID string

	// DeploymentStatus captures the status of the allocation as part of the
	// given deployment
	DeploymentStatus *AllocDeploymentStatus

	// RescheduleTrackers captures details of previous reschedule attempts of the allocation
	RescheduleTracker *RescheduleTracker

	// FollowupEvalID captures a follow up evaluation created to handle a failed allocation
	// that can be rescheduled in the future
	FollowupEvalID string

	// PreemptedAllocations captures IDs of any allocations that were preempted
	// in order to place this allocation
	PreemptedAllocations []string

	// PreemptedByAllocation tracks the alloc ID of the allocation that caused this allocation
	// to stop running because it got preempted
	PreemptedByAllocation string

	// Raft Indexes
	CreateIndex uint64
	ModifyIndex uint64

	// AllocModifyIndex is not updated when the client updates allocations. This
	// lets the client pull only the allocs updated by the server.
	AllocModifyIndex uint64

	// CreateTime is the time the allocation has finished scheduling and been
	// verified by the plan applier.
	CreateTime int64

	// ModifyTime is the time the allocation was last updated.
	ModifyTime int64
}

// Index returns the index of the allocation. If the allocation is from a task
// group with count greater than 1, there will be multiple allocations for it.
func (a *Allocation) Index() uint {
	l := len(a.Name)
	prefix := len(a.JobID) + len(a.TaskGroup) + 2
	if l <= 3 || l <= prefix {
		return uint(0)
	}

	strNum := a.Name[prefix : len(a.Name)-1]
	num, _ := strconv.Atoi(strNum)
	return uint(num)
}

func (a *Allocation) Copy() *Allocation {
	return a.copyImpl(true)
}

// Copy provides a copy of the allocation but doesn't deep copy the job
func (a *Allocation) CopySkipJob() *Allocation {
	return a.copyImpl(false)
}

func (a *Allocation) copyImpl(job bool) *Allocation {
	if a == nil {
		return nil
	}
	na := new(Allocation)
	*na = *a

	if job {
		na.Job = na.Job.Copy()
	}

	na.AllocatedResources = na.AllocatedResources.Copy()
	na.Resources = na.Resources.Copy()
	na.SharedResources = na.SharedResources.Copy()

	if a.TaskResources != nil {
		tr := make(map[string]*Resources, len(na.TaskResources))
		for task, resource := range na.TaskResources {
			tr[task] = resource.Copy()
		}
		na.TaskResources = tr
	}

	na.Metrics = na.Metrics.Copy()
	na.DeploymentStatus = na.DeploymentStatus.Copy()

	if a.TaskStates != nil {
		ts := make(map[string]*TaskState, len(na.TaskStates))
		for task, state := range na.TaskStates {
			ts[task] = state.Copy()
		}
		na.TaskStates = ts
	}

	na.RescheduleTracker = a.RescheduleTracker.Copy()
	na.PreemptedAllocations = helper.CopySliceString(a.PreemptedAllocations)
	return na
}

// TerminalStatus returns if the desired or actual status is terminal and
// will no longer transition.
func (a *Allocation) TerminalStatus() bool {
	// First check the desired state and if that isn't terminal, check client
	// state.
	return a.ServerTerminalStatus() || a.ClientTerminalStatus()
}

// ServerTerminalStatus returns true if the desired state of the allocation is terminal
func (a *Allocation) ServerTerminalStatus() bool {
	switch a.DesiredStatus {
	case AllocDesiredStatusStop, AllocDesiredStatusEvict:
		return true
	default:
		return false
	}
}

// ClientTerminalStatus returns if the client status is terminal and will no longer transition
func (a *Allocation) ClientTerminalStatus() bool {
	switch a.ClientStatus {
	case AllocClientStatusComplete, AllocClientStatusFailed, AllocClientStatusLost:
		return true
	default:
		return false
	}
}

// ShouldReschedule returns if the allocation is eligible to be rescheduled according
// to its status and ReschedulePolicy given its failure time
func (a *Allocation) ShouldReschedule(reschedulePolicy *ReschedulePolicy, failTime time.Time) bool {
	// First check the desired state
	switch a.DesiredStatus {
	case AllocDesiredStatusStop, AllocDesiredStatusEvict:
		return false
	default:
	}
	switch a.ClientStatus {
	case AllocClientStatusFailed:
		return a.RescheduleEligible(reschedulePolicy, failTime)
	default:
		return false
	}
}

// RescheduleEligible returns if the allocation is eligible to be rescheduled according
// to its ReschedulePolicy and the current state of its reschedule trackers
func (a *Allocation) RescheduleEligible(reschedulePolicy *ReschedulePolicy, failTime time.Time) bool {
	if reschedulePolicy == nil {
		return false
	}
	attempts := reschedulePolicy.Attempts
	interval := reschedulePolicy.Interval
	enabled := attempts > 0 || reschedulePolicy.Unlimited
	if !enabled {
		return false
	}
	if reschedulePolicy.Unlimited {
		return true
	}
	// Early return true if there are no attempts yet and the number of allowed attempts is > 0
	if (a.RescheduleTracker == nil || len(a.RescheduleTracker.Events) == 0) && attempts > 0 {
		return true
	}
	attempted := 0
	for j := len(a.RescheduleTracker.Events) - 1; j >= 0; j-- {
		lastAttempt := a.RescheduleTracker.Events[j].RescheduleTime
		timeDiff := failTime.UTC().UnixNano() - lastAttempt
		if timeDiff < interval.Nanoseconds() {
			attempted += 1
		}
	}
	return attempted < attempts
}

// LastEventTime is the time of the last task event in the allocation.
// It is used to determine allocation failure time. If the FinishedAt field
// is not set, the alloc's modify time is used
func (a *Allocation) LastEventTime() time.Time {
	var lastEventTime time.Time
	if a.TaskStates != nil {
		for _, s := range a.TaskStates {
			if lastEventTime.IsZero() || s.FinishedAt.After(lastEventTime) {
				lastEventTime = s.FinishedAt
			}
		}
	}

	if lastEventTime.IsZero() {
		return time.Unix(0, a.ModifyTime).UTC()
	}
	return lastEventTime
}

// ReschedulePolicy returns the reschedule policy based on the task group
func (a *Allocation) ReschedulePolicy() *ReschedulePolicy {
	tg := a.Job.LookupTaskGroup(a.TaskGroup)
	if tg == nil {
		return nil
	}
	return tg.ReschedulePolicy
}

// NextRescheduleTime returns a time on or after which the allocation is eligible to be rescheduled,
// and whether the next reschedule time is within policy's interval if the policy doesn't allow unlimited reschedules
func (a *Allocation) NextRescheduleTime() (time.Time, bool) {
	failTime := a.LastEventTime()
	reschedulePolicy := a.ReschedulePolicy()
	if a.DesiredStatus == AllocDesiredStatusStop || a.ClientStatus != AllocClientStatusFailed || failTime.IsZero() || reschedulePolicy == nil {
		return time.Time{}, false
	}

	nextDelay := a.NextDelay()
	nextRescheduleTime := failTime.Add(nextDelay)
	rescheduleEligible := reschedulePolicy.Unlimited || (reschedulePolicy.Attempts > 0 && a.RescheduleTracker == nil)
	if reschedulePolicy.Attempts > 0 && a.RescheduleTracker != nil && a.RescheduleTracker.Events != nil {
		// Check for eligibility based on the interval if max attempts is set
		attempted := 0
		for j := len(a.RescheduleTracker.Events) - 1; j >= 0; j-- {
			lastAttempt := a.RescheduleTracker.Events[j].RescheduleTime
			timeDiff := failTime.UTC().UnixNano() - lastAttempt
			if timeDiff < reschedulePolicy.Interval.Nanoseconds() {
				attempted += 1
			}
		}
		rescheduleEligible = attempted < reschedulePolicy.Attempts && nextDelay < reschedulePolicy.Interval
	}
	return nextRescheduleTime, rescheduleEligible
}

// NextDelay returns a duration after which the allocation can be rescheduled.
// It is calculated according to the delay function and previous reschedule attempts.
func (a *Allocation) NextDelay() time.Duration {
	policy := a.ReschedulePolicy()
	// Can be nil if the task group was updated to remove its reschedule policy
	if policy == nil {
		return 0
	}
	delayDur := policy.Delay
	if a.RescheduleTracker == nil || a.RescheduleTracker.Events == nil || len(a.RescheduleTracker.Events) == 0 {
		return delayDur
	}
	events := a.RescheduleTracker.Events
	switch policy.DelayFunction {
	case "exponential":
		delayDur = a.RescheduleTracker.Events[len(a.RescheduleTracker.Events)-1].Delay * 2
	case "fibonacci":
		if len(events) >= 2 {
			fibN1Delay := events[len(events)-1].Delay
			fibN2Delay := events[len(events)-2].Delay
			// Handle reset of delay ceiling which should cause
			// a new series to start
			if fibN2Delay == policy.MaxDelay && fibN1Delay == policy.Delay {
				delayDur = fibN1Delay
			} else {
				delayDur = fibN1Delay + fibN2Delay
			}
		}
	default:
		return delayDur
	}
	if policy.MaxDelay > 0 && delayDur > policy.MaxDelay {
		delayDur = policy.MaxDelay
		// check if delay needs to be reset

		lastRescheduleEvent := a.RescheduleTracker.Events[len(a.RescheduleTracker.Events)-1]
		timeDiff := a.LastEventTime().UTC().UnixNano() - lastRescheduleEvent.RescheduleTime
		if timeDiff > delayDur.Nanoseconds() {
			delayDur = policy.Delay
		}

	}

	return delayDur
}

// Terminated returns if the allocation is in a terminal state on a client.
func (a *Allocation) Terminated() bool {
	if a.ClientStatus == AllocClientStatusFailed ||
		a.ClientStatus == AllocClientStatusComplete ||
		a.ClientStatus == AllocClientStatusLost {
		return true
	}
	return false
}

// RanSuccessfully returns whether the client has ran the allocation and all
// tasks finished successfully. Critically this function returns whether the
// allocation has ran to completion and not just that the alloc has converged to
// its desired state. That is to say that a batch allocation must have finished
// with exit code 0 on all task groups. This doesn't really have meaning on a
// non-batch allocation because a service and system allocation should not
// finish.
func (a *Allocation) RanSuccessfully() bool {
	// Handle the case the client hasn't started the allocation.
	if len(a.TaskStates) == 0 {
		return false
	}

	// Check to see if all the tasks finished successfully in the allocation
	allSuccess := true
	for _, state := range a.TaskStates {
		allSuccess = allSuccess && state.Successful()
	}

	return allSuccess
}

// ShouldMigrate returns if the allocation needs data migration
func (a *Allocation) ShouldMigrate() bool {
	if a.PreviousAllocation == "" {
		return false
	}

	if a.DesiredStatus == AllocDesiredStatusStop || a.DesiredStatus == AllocDesiredStatusEvict {
		return false
	}

	tg := a.Job.LookupTaskGroup(a.TaskGroup)

	// if the task group is nil or the ephemeral disk block isn't present then
	// we won't migrate
	if tg == nil || tg.EphemeralDisk == nil {
		return false
	}

	// We won't migrate any data is the user hasn't enabled migration or the
	// disk is not marked as sticky
	if !tg.EphemeralDisk.Migrate || !tg.EphemeralDisk.Sticky {
		return false
	}

	return true
}

// SetEventDisplayMessage populates the display message if its not already set,
// a temporary fix to handle old allocations that don't have it.
// This method will be removed in a future release.
func (a *Allocation) SetEventDisplayMessages() {
	setDisplayMsg(a.TaskStates)
}

// COMPAT(0.11): Remove in 0.11
// ComparableResources returns the resouces on the allocation
// handling upgrade paths. After 0.11 calls to this should be replaced with:
// alloc.AllocatedResources.Comparable()
func (a *Allocation) ComparableResources() *ComparableResources {
	// ALloc already has 0.9+ behavior
	if a.AllocatedResources != nil {
		return a.AllocatedResources.Comparable()
	}

	var resources *Resources
	if a.Resources != nil {
		resources = a.Resources
	} else if a.TaskResources != nil {
		resources = new(Resources)
		resources.Add(a.SharedResources)
		for _, taskResource := range a.TaskResources {
			resources.Add(taskResource)
		}
	}

	// Upgrade path
	return &ComparableResources{
		Flattened: AllocatedTaskResources{
			Cpu: AllocatedCpuResources{
				CpuShares: int64(resources.CPU),
			},
			Memory: AllocatedMemoryResources{
				MemoryMB: int64(resources.MemoryMB),
			},
			Networks: resources.Networks,
		},
		Shared: AllocatedSharedResources{
			DiskMB: int64(resources.DiskMB),
		},
	}
}

// LookupTask by name from the Allocation. Returns nil if the Job is not set, the
// TaskGroup does not exist, or the task name cannot be found.
func (a *Allocation) LookupTask(name string) *Task {
	if a.Job == nil {
		return nil
	}

	tg := a.Job.LookupTaskGroup(a.TaskGroup)
	if tg == nil {
		return nil
	}

	return tg.LookupTask(name)
}

// Stub returns a list stub for the allocation
func (a *Allocation) Stub() *AllocListStub {
	return &AllocListStub{
		ID:                 a.ID,
		EvalID:             a.EvalID,
		Name:               a.Name,
		Namespace:          a.Namespace,
		NodeID:             a.NodeID,
		JobID:              a.JobID,
		JobType:            a.Job.Type,
		JobVersion:         a.Job.Version,
		TaskGroup:          a.TaskGroup,
		DesiredStatus:      a.DesiredStatus,
		DesiredDescription: a.DesiredDescription,
		ClientStatus:       a.ClientStatus,
		ClientDescription:  a.ClientDescription,
		DesiredTransition:  a.DesiredTransition,
		TaskStates:         a.TaskStates,
		DeploymentStatus:   a.DeploymentStatus,
		FollowupEvalID:     a.FollowupEvalID,
		RescheduleTracker:  a.RescheduleTracker,
		CreateIndex:        a.CreateIndex,
		ModifyIndex:        a.ModifyIndex,
		CreateTime:         a.CreateTime,
		ModifyTime:         a.ModifyTime,
	}
}

// AllocListStub is used to return a subset of alloc information
type AllocListStub struct {
	ID                 string
	EvalID             string
	Name               string
	Namespace          string
	NodeID             string
	JobID              string
	JobType            string
	JobVersion         uint64
	TaskGroup          string
	DesiredStatus      string
	DesiredDescription string
	ClientStatus       string
	ClientDescription  string
	DesiredTransition  DesiredTransition
	TaskStates         map[string]*TaskState
	DeploymentStatus   *AllocDeploymentStatus
	FollowupEvalID     string
	RescheduleTracker  *RescheduleTracker
	CreateIndex        uint64
	ModifyIndex        uint64
	CreateTime         int64
	ModifyTime         int64
}

// SetEventDisplayMessage populates the display message if its not already set,
// a temporary fix to handle old allocations that don't have it.
// This method will be removed in a future release.
func (a *AllocListStub) SetEventDisplayMessages() {
	setDisplayMsg(a.TaskStates)
}

func setDisplayMsg(taskStates map[string]*TaskState) {
	if taskStates != nil {
		for _, taskState := range taskStates {
			for _, event := range taskState.Events {
				event.PopulateEventDisplayMessage()
			}
		}
	}
}

// AllocMetric is used to track various metrics while attempting
// to make an allocation. These are used to debug a job, or to better
// understand the pressure within the system.
type AllocMetric struct {
	// NodesEvaluated is the number of nodes that were evaluated
	NodesEvaluated int

	// NodesFiltered is the number of nodes filtered due to a constraint
	NodesFiltered int

	// NodesAvailable is the number of nodes available for evaluation per DC.
	NodesAvailable map[string]int

	// ClassFiltered is the number of nodes filtered by class
	ClassFiltered map[string]int

	// ConstraintFiltered is the number of failures caused by constraint
	ConstraintFiltered map[string]int

	// NodesExhausted is the number of nodes skipped due to being
	// exhausted of at least one resource
	NodesExhausted int

	// ClassExhausted is the number of nodes exhausted by class
	ClassExhausted map[string]int

	// DimensionExhausted provides the count by dimension or reason
	DimensionExhausted map[string]int

	// QuotaExhausted provides the exhausted dimensions
	QuotaExhausted []string

	// Scores is the scores of the final few nodes remaining
	// for placement. The top score is typically selected.
	// Deprecated: Replaced by ScoreMetaData in Nomad 0.9
	Scores map[string]float64

	// ScoreMetaData is a slice of top scoring nodes displayed in the CLI
	ScoreMetaData []*NodeScoreMeta

	// nodeScoreMeta is used to keep scores for a single node id. It is cleared out after
	// we receive normalized score during the last step of the scoring stack.
	nodeScoreMeta *NodeScoreMeta

	// topScores is used to maintain a heap of the top K nodes with
	// the highest normalized score
	topScores *kheap.ScoreHeap

	// AllocationTime is a measure of how long the allocation
	// attempt took. This can affect performance and SLAs.
	AllocationTime time.Duration

	// CoalescedFailures indicates the number of other
	// allocations that were coalesced into this failed allocation.
	// This is to prevent creating many failed allocations for a
	// single task group.
	CoalescedFailures int
}

func (a *AllocMetric) Copy() *AllocMetric {
	if a == nil {
		return nil
	}
	na := new(AllocMetric)
	*na = *a
	na.NodesAvailable = helper.CopyMapStringInt(na.NodesAvailable)
	na.ClassFiltered = helper.CopyMapStringInt(na.ClassFiltered)
	na.ConstraintFiltered = helper.CopyMapStringInt(na.ConstraintFiltered)
	na.ClassExhausted = helper.CopyMapStringInt(na.ClassExhausted)
	na.DimensionExhausted = helper.CopyMapStringInt(na.DimensionExhausted)
	na.QuotaExhausted = helper.CopySliceString(na.QuotaExhausted)
	na.Scores = helper.CopyMapStringFloat64(na.Scores)
	na.ScoreMetaData = CopySliceNodeScoreMeta(na.ScoreMetaData)
	return na
}

func (a *AllocMetric) EvaluateNode() {
	a.NodesEvaluated += 1
}

func (a *AllocMetric) FilterNode(node *Node, constraint string) {
	a.NodesFiltered += 1
	if node != nil && node.NodeClass != "" {
		if a.ClassFiltered == nil {
			a.ClassFiltered = make(map[string]int)
		}
		a.ClassFiltered[node.NodeClass] += 1
	}
	if constraint != "" {
		if a.ConstraintFiltered == nil {
			a.ConstraintFiltered = make(map[string]int)
		}
		a.ConstraintFiltered[constraint] += 1
	}
}

func (a *AllocMetric) ExhaustedNode(node *Node, dimension string) {
	a.NodesExhausted += 1
	if node != nil && node.NodeClass != "" {
		if a.ClassExhausted == nil {
			a.ClassExhausted = make(map[string]int)
		}
		a.ClassExhausted[node.NodeClass] += 1
	}
	if dimension != "" {
		if a.DimensionExhausted == nil {
			a.DimensionExhausted = make(map[string]int)
		}
		a.DimensionExhausted[dimension] += 1
	}
}

func (a *AllocMetric) ExhaustQuota(dimensions []string) {
	if a.QuotaExhausted == nil {
		a.QuotaExhausted = make([]string, 0, len(dimensions))
	}

	a.QuotaExhausted = append(a.QuotaExhausted, dimensions...)
}

// ScoreNode is used to gather top K scoring nodes in a heap
func (a *AllocMetric) ScoreNode(node *Node, name string, score float64) {
	// Create nodeScoreMeta lazily if its the first time or if its a new node
	if a.nodeScoreMeta == nil || a.nodeScoreMeta.NodeID != node.ID {
		a.nodeScoreMeta = &NodeScoreMeta{
			NodeID: node.ID,
			Scores: make(map[string]float64),
		}
	}
	if name == NormScorerName {
		a.nodeScoreMeta.NormScore = score
		// Once we have the normalized score we can push to the heap
		// that tracks top K by normalized score

		// Create the heap if its not there already
		if a.topScores == nil {
			a.topScores = kheap.NewScoreHeap(MaxRetainedNodeScores)
		}
		heap.Push(a.topScores, a.nodeScoreMeta)

		// Clear out this entry because its now in the heap
		a.nodeScoreMeta = nil
	} else {
		a.nodeScoreMeta.Scores[name] = score
	}
}

// PopulateScoreMetaData populates a map of scorer to scoring metadata
// The map is populated by popping elements from a heap of top K scores
// maintained per scorer
func (a *AllocMetric) PopulateScoreMetaData() {
	if a.topScores == nil {
		return
	}

	if a.ScoreMetaData == nil {
		a.ScoreMetaData = make([]*NodeScoreMeta, a.topScores.Len())
	}
	heapItems := a.topScores.GetItemsReverse()
	for i, item := range heapItems {
		a.ScoreMetaData[i] = item.(*NodeScoreMeta)
	}
}

// NodeScoreMeta captures scoring meta data derived from
// different scoring factors.
type NodeScoreMeta struct {
	NodeID    string
	Scores    map[string]float64
	NormScore float64
}

func (s *NodeScoreMeta) Copy() *NodeScoreMeta {
	if s == nil {
		return nil
	}
	ns := new(NodeScoreMeta)
	*ns = *s
	return ns
}

func (s *NodeScoreMeta) String() string {
	return fmt.Sprintf("%s %f %v", s.NodeID, s.NormScore, s.Scores)
}

func (s *NodeScoreMeta) Score() float64 {
	return s.NormScore
}

func (s *NodeScoreMeta) Data() interface{} {
	return s
}

// AllocDeploymentStatus captures the status of the allocation as part of the
// deployment. This can include things like if the allocation has been marked as
// healthy.
type AllocDeploymentStatus struct {
	// Healthy marks whether the allocation has been marked healthy or unhealthy
	// as part of a deployment. It can be unset if it has neither been marked
	// healthy or unhealthy.
	Healthy *bool

	// Timestamp is the time at which the health status was set.
	Timestamp time.Time

	// Canary marks whether the allocation is a canary or not. A canary that has
	// been promoted will have this field set to false.
	Canary bool

	// ModifyIndex is the raft index in which the deployment status was last
	// changed.
	ModifyIndex uint64
}

// HasHealth returns true if the allocation has its health set.
func (a *AllocDeploymentStatus) HasHealth() bool {
	return a != nil && a.Healthy != nil
}

// IsHealthy returns if the allocation is marked as healthy as part of a
// deployment
func (a *AllocDeploymentStatus) IsHealthy() bool {
	if a == nil {
		return false
	}

	return a.Healthy != nil && *a.Healthy
}

// IsUnhealthy returns if the allocation is marked as unhealthy as part of a
// deployment
func (a *AllocDeploymentStatus) IsUnhealthy() bool {
	if a == nil {
		return false
	}

	return a.Healthy != nil && !*a.Healthy
}

// IsCanary returns if the allocation is marked as a canary
func (a *AllocDeploymentStatus) IsCanary() bool {
	if a == nil {
		return false
	}

	return a.Canary
}

func (a *AllocDeploymentStatus) Copy() *AllocDeploymentStatus {
	if a == nil {
		return nil
	}

	c := new(AllocDeploymentStatus)
	*c = *a

	if a.Healthy != nil {
		c.Healthy = helper.BoolToPtr(*a.Healthy)
	}

	return c
}

const (
	EvalStatusBlocked   = "blocked"
	EvalStatusPending   = "pending"
	EvalStatusComplete  = "complete"
	EvalStatusFailed    = "failed"
	EvalStatusCancelled = "canceled"
)

const (
	EvalTriggerJobRegister       = "job-register"
	EvalTriggerJobDeregister     = "job-deregister"
	EvalTriggerPeriodicJob       = "periodic-job"
	EvalTriggerNodeDrain         = "node-drain"
	EvalTriggerNodeUpdate        = "node-update"
	EvalTriggerScheduled         = "scheduled"
	EvalTriggerRollingUpdate     = "rolling-update"
	EvalTriggerDeploymentWatcher = "deployment-watcher"
	EvalTriggerFailedFollowUp    = "failed-follow-up"
	EvalTriggerMaxPlans          = "max-plan-attempts"
	EvalTriggerRetryFailedAlloc  = "alloc-failure"
	EvalTriggerQueuedAllocs      = "queued-allocs"
	EvalTriggerPreemption        = "preemption"
)

const (
	// CoreJobEvalGC is used for the garbage collection of evaluations
	// and allocations. We periodically scan evaluations in a terminal state,
	// in which all the corresponding allocations are also terminal. We
	// delete these out of the system to bound the state.
	CoreJobEvalGC = "eval-gc"

	// CoreJobNodeGC is used for the garbage collection of failed nodes.
	// We periodically scan nodes in a terminal state, and if they have no
	// corresponding allocations we delete these out of the system.
	CoreJobNodeGC = "node-gc"

	// CoreJobJobGC is used for the garbage collection of eligible jobs. We
	// periodically scan garbage collectible jobs and check if both their
	// evaluations and allocations are terminal. If so, we delete these out of
	// the system.
	CoreJobJobGC = "job-gc"

	// CoreJobDeploymentGC is used for the garbage collection of eligible
	// deployments. We periodically scan garbage collectible deployments and
	// check if they are terminal. If so, we delete these out of the system.
	CoreJobDeploymentGC = "deployment-gc"

	// CoreJobForceGC is used to force garbage collection of all GCable objects.
	CoreJobForceGC = "force-gc"
)

// Evaluation is used anytime we need to apply business logic as a result
// of a change to our desired state (job specification) or the emergent state
// (registered nodes). When the inputs change, we need to "evaluate" them,
// potentially taking action (allocation of work) or doing nothing if the state
// of the world does not require it.
type Evaluation struct {
	// ID is a randomly generated UUID used for this evaluation. This
	// is assigned upon the creation of the evaluation.
	ID string

	// Namespace is the namespace the evaluation is created in
	Namespace string

	// Priority is used to control scheduling importance and if this job
	// can preempt other jobs.
	Priority int

	// Type is used to control which schedulers are available to handle
	// this evaluation.
	Type string

	// TriggeredBy is used to give some insight into why this Eval
	// was created. (Job change, node failure, alloc failure, etc).
	TriggeredBy string

	// JobID is the job this evaluation is scoped to. Evaluations cannot
	// be run in parallel for a given JobID, so we serialize on this.
	JobID string

	// JobModifyIndex is the modify index of the job at the time
	// the evaluation was created
	JobModifyIndex uint64

	// NodeID is the node that was affected triggering the evaluation.
	NodeID string

	// NodeModifyIndex is the modify index of the node at the time
	// the evaluation was created
	NodeModifyIndex uint64

	// DeploymentID is the ID of the deployment that triggered the evaluation.
	DeploymentID string

	// Status of the evaluation
	Status string

	// StatusDescription is meant to provide more human useful information
	StatusDescription string

	// Wait is a minimum wait time for running the eval. This is used to
	// support a rolling upgrade in versions prior to 0.7.0
	// Deprecated
	Wait time.Duration

	// WaitUntil is the time when this eval should be run. This is used to
	// supported delayed rescheduling of failed allocations
	WaitUntil time.Time

	// NextEval is the evaluation ID for the eval created to do a followup.
	// This is used to support rolling upgrades and failed-follow-up evals, where
	// we need a chain of evaluations.
	NextEval string

	// PreviousEval is the evaluation ID for the eval creating this one to do a followup.
	// This is used to support rolling upgrades and failed-follow-up evals, where
	// we need a chain of evaluations.
	PreviousEval string

	// BlockedEval is the evaluation ID for a created blocked eval. A
	// blocked eval will be created if all allocations could not be placed due
	// to constraints or lacking resources.
	BlockedEval string

	// FailedTGAllocs are task groups which have allocations that could not be
	// made, but the metrics are persisted so that the user can use the feedback
	// to determine the cause.
	FailedTGAllocs map[string]*AllocMetric

	// ClassEligibility tracks computed node classes that have been explicitly
	// marked as eligible or ineligible.
	ClassEligibility map[string]bool

	// QuotaLimitReached marks whether a quota limit was reached for the
	// evaluation.
	QuotaLimitReached string

	// EscapedComputedClass marks whether the job has constraints that are not
	// captured by computed node classes.
	EscapedComputedClass bool

	// AnnotatePlan triggers the scheduler to provide additional annotations
	// during the evaluation. This should not be set during normal operations.
	AnnotatePlan bool

	// QueuedAllocations is the number of unplaced allocations at the time the
	// evaluation was processed. The map is keyed by Task Group names.
	QueuedAllocations map[string]int

	// LeaderACL provides the ACL token to when issuing RPCs back to the
	// leader. This will be a valid management token as long as the leader is
	// active. This should not ever be exposed via the API.
	LeaderACL string

	// SnapshotIndex is the Raft index of the snapshot used to process the
	// evaluation. The index will either be set when it has gone through the
	// scheduler or if a blocked evaluation is being created. The index is set
	// in this case so we can determine if an early unblocking is required since
	// capacity has changed since the evaluation was created. This can result in
	// the SnapshotIndex being less than the CreateIndex.
	SnapshotIndex uint64

	// Raft Indexes
	CreateIndex uint64
	ModifyIndex uint64
}

// TerminalStatus returns if the current status is terminal and
// will no longer transition.
func (e *Evaluation) TerminalStatus() bool {
	switch e.Status {
	case EvalStatusComplete, EvalStatusFailed, EvalStatusCancelled:
		return true
	default:
		return false
	}
}

func (e *Evaluation) GoString() string {
	return fmt.Sprintf("<Eval %q JobID: %q Namespace: %q>", e.ID, e.JobID, e.Namespace)
}

func (e *Evaluation) Copy() *Evaluation {
	if e == nil {
		return nil
	}
	ne := new(Evaluation)
	*ne = *e

	// Copy ClassEligibility
	if e.ClassEligibility != nil {
		classes := make(map[string]bool, len(e.ClassEligibility))
		for class, elig := range e.ClassEligibility {
			classes[class] = elig
		}
		ne.ClassEligibility = classes
	}

	// Copy FailedTGAllocs
	if e.FailedTGAllocs != nil {
		failedTGs := make(map[string]*AllocMetric, len(e.FailedTGAllocs))
		for tg, metric := range e.FailedTGAllocs {
			failedTGs[tg] = metric.Copy()
		}
		ne.FailedTGAllocs = failedTGs
	}

	// Copy queued allocations
	if e.QueuedAllocations != nil {
		queuedAllocations := make(map[string]int, len(e.QueuedAllocations))
		for tg, num := range e.QueuedAllocations {
			queuedAllocations[tg] = num
		}
		ne.QueuedAllocations = queuedAllocations
	}

	return ne
}

// ShouldEnqueue checks if a given evaluation should be enqueued into the
// eval_broker
func (e *Evaluation) ShouldEnqueue() bool {
	switch e.Status {
	case EvalStatusPending:
		return true
	case EvalStatusComplete, EvalStatusFailed, EvalStatusBlocked, EvalStatusCancelled:
		return false
	default:
		panic(fmt.Sprintf("unhandled evaluation (%s) status %s", e.ID, e.Status))
	}
}

// ShouldBlock checks if a given evaluation should be entered into the blocked
// eval tracker.
func (e *Evaluation) ShouldBlock() bool {
	switch e.Status {
	case EvalStatusBlocked:
		return true
	case EvalStatusComplete, EvalStatusFailed, EvalStatusPending, EvalStatusCancelled:
		return false
	default:
		panic(fmt.Sprintf("unhandled evaluation (%s) status %s", e.ID, e.Status))
	}
}

// MakePlan is used to make a plan from the given evaluation
// for a given Job
func (e *Evaluation) MakePlan(j *Job) *Plan {
	p := &Plan{
		EvalID:          e.ID,
		Priority:        e.Priority,
		Job:             j,
		NodeUpdate:      make(map[string][]*Allocation),
		NodeAllocation:  make(map[string][]*Allocation),
		NodePreemptions: make(map[string][]*Allocation),
	}
	if j != nil {
		p.AllAtOnce = j.AllAtOnce
	}
	return p
}

// NextRollingEval creates an evaluation to followup this eval for rolling updates
func (e *Evaluation) NextRollingEval(wait time.Duration) *Evaluation {
	return &Evaluation{
		ID:             uuid.Generate(),
		Namespace:      e.Namespace,
		Priority:       e.Priority,
		Type:           e.Type,
		TriggeredBy:    EvalTriggerRollingUpdate,
		JobID:          e.JobID,
		JobModifyIndex: e.JobModifyIndex,
		Status:         EvalStatusPending,
		Wait:           wait,
		PreviousEval:   e.ID,
	}
}

// CreateBlockedEval creates a blocked evaluation to followup this eval to place any
// failed allocations. It takes the classes marked explicitly eligible or
// ineligible, whether the job has escaped computed node classes and whether the
// quota limit was reached.
func (e *Evaluation) CreateBlockedEval(classEligibility map[string]bool,
	escaped bool, quotaReached string) *Evaluation {

	return &Evaluation{
		ID:                   uuid.Generate(),
		Namespace:            e.Namespace,
		Priority:             e.Priority,
		Type:                 e.Type,
		TriggeredBy:          EvalTriggerQueuedAllocs,
		JobID:                e.JobID,
		JobModifyIndex:       e.JobModifyIndex,
		Status:               EvalStatusBlocked,
		PreviousEval:         e.ID,
		ClassEligibility:     classEligibility,
		EscapedComputedClass: escaped,
		QuotaLimitReached:    quotaReached,
	}
}

// CreateFailedFollowUpEval creates a follow up evaluation when the current one
// has been marked as failed because it has hit the delivery limit and will not
// be retried by the eval_broker. Callers should copy the created eval's ID to
// into the old eval's NextEval field.
func (e *Evaluation) CreateFailedFollowUpEval(wait time.Duration) *Evaluation {
	return &Evaluation{
		ID:             uuid.Generate(),
		Namespace:      e.Namespace,
		Priority:       e.Priority,
		Type:           e.Type,
		TriggeredBy:    EvalTriggerFailedFollowUp,
		JobID:          e.JobID,
		JobModifyIndex: e.JobModifyIndex,
		Status:         EvalStatusPending,
		Wait:           wait,
		PreviousEval:   e.ID,
	}
}

// Plan is used to submit a commit plan for task allocations. These
// are submitted to the leader which verifies that resources have
// not been overcommitted before admitting the plan.
type Plan struct {
	// EvalID is the evaluation ID this plan is associated with
	EvalID string

	// EvalToken is used to prevent a split-brain processing of
	// an evaluation. There should only be a single scheduler running
	// an Eval at a time, but this could be violated after a leadership
	// transition. This unique token is used to reject plans that are
	// being submitted from a different leader.
	EvalToken string

	// Priority is the priority of the upstream job
	Priority int

	// AllAtOnce is used to control if incremental scheduling of task groups
	// is allowed or if we must do a gang scheduling of the entire job.
	// If this is false, a plan may be partially applied. Otherwise, the
	// entire plan must be able to make progress.
	AllAtOnce bool

	// Job is the parent job of all the allocations in the Plan.
	// Since a Plan only involves a single Job, we can reduce the size
	// of the plan by only including it once.
	Job *Job

	// NodeUpdate contains all the allocations for each node. For each node,
	// this is a list of the allocations to update to either stop or evict.
	NodeUpdate map[string][]*Allocation

	// NodeAllocation contains all the allocations for each node.
	// The evicts must be considered prior to the allocations.
	NodeAllocation map[string][]*Allocation

	// Annotations contains annotations by the scheduler to be used by operators
	// to understand the decisions made by the scheduler.
	Annotations *PlanAnnotations

	// Deployment is the deployment created or updated by the scheduler that
	// should be applied by the planner.
	Deployment *Deployment

	// DeploymentUpdates is a set of status updates to apply to the given
	// deployments. This allows the scheduler to cancel any unneeded deployment
	// because the job is stopped or the update block is removed.
	DeploymentUpdates []*DeploymentStatusUpdate

	// NodePreemptions is a map from node id to a set of allocations from other
	// lower priority jobs that are preempted. Preempted allocations are marked
	// as evicted.
	NodePreemptions map[string][]*Allocation
}

// AppendUpdate marks the allocation for eviction. The clientStatus of the
// allocation may be optionally set by passing in a non-empty value.
func (p *Plan) AppendUpdate(alloc *Allocation, desiredStatus, desiredDesc, clientStatus string) {
	newAlloc := new(Allocation)
	*newAlloc = *alloc

	// If the job is not set in the plan we are deregistering a job so we
	// extract the job from the allocation.
	if p.Job == nil && newAlloc.Job != nil {
		p.Job = newAlloc.Job
	}

	// Normalize the job
	newAlloc.Job = nil

	// Strip the resources as it can be rebuilt.
	newAlloc.Resources = nil

	newAlloc.DesiredStatus = desiredStatus
	newAlloc.DesiredDescription = desiredDesc

	if clientStatus != "" {
		newAlloc.ClientStatus = clientStatus
	}

	node := alloc.NodeID
	existing := p.NodeUpdate[node]
	p.NodeUpdate[node] = append(existing, newAlloc)
}

// AppendPreemptedAlloc is used to append an allocation that's being preempted to the plan.
// To minimize the size of the plan, this only sets a minimal set of fields in the allocation
func (p *Plan) AppendPreemptedAlloc(alloc *Allocation, desiredStatus, preemptingAllocID string) {
	newAlloc := &Allocation{}
	newAlloc.ID = alloc.ID
	newAlloc.JobID = alloc.JobID
	newAlloc.Namespace = alloc.Namespace
	newAlloc.DesiredStatus = desiredStatus
	newAlloc.PreemptedByAllocation = preemptingAllocID

	desiredDesc := fmt.Sprintf("Preempted by alloc ID %v", preemptingAllocID)
	newAlloc.DesiredDescription = desiredDesc

	// TaskResources are needed by the plan applier to check if allocations fit
	// after removing preempted allocations
	if alloc.AllocatedResources != nil {
		newAlloc.AllocatedResources = alloc.AllocatedResources
	} else {
		// COMPAT Remove in version 0.11
		newAlloc.TaskResources = alloc.TaskResources
		newAlloc.SharedResources = alloc.SharedResources
	}

	// Append this alloc to slice for this node
	node := alloc.NodeID
	existing := p.NodePreemptions[node]
	p.NodePreemptions[node] = append(existing, newAlloc)
}

func (p *Plan) PopUpdate(alloc *Allocation) {
	existing := p.NodeUpdate[alloc.NodeID]
	n := len(existing)
	if n > 0 && existing[n-1].ID == alloc.ID {
		existing = existing[:n-1]
		if len(existing) > 0 {
			p.NodeUpdate[alloc.NodeID] = existing
		} else {
			delete(p.NodeUpdate, alloc.NodeID)
		}
	}
}

func (p *Plan) AppendAlloc(alloc *Allocation) {
	node := alloc.NodeID
	existing := p.NodeAllocation[node]

	// Normalize the job
	alloc.Job = nil

	p.NodeAllocation[node] = append(existing, alloc)
}

// IsNoOp checks if this plan would do nothing
func (p *Plan) IsNoOp() bool {
	return len(p.NodeUpdate) == 0 &&
		len(p.NodeAllocation) == 0 &&
		p.Deployment == nil &&
		len(p.DeploymentUpdates) == 0
}

// PlanResult is the result of a plan submitted to the leader.
type PlanResult struct {
	// NodeUpdate contains all the updates that were committed.
	NodeUpdate map[string][]*Allocation

	// NodeAllocation contains all the allocations that were committed.
	NodeAllocation map[string][]*Allocation

	// Deployment is the deployment that was committed.
	Deployment *Deployment

	// DeploymentUpdates is the set of deployment updates that were committed.
	DeploymentUpdates []*DeploymentStatusUpdate

	// NodePreemptions is a map from node id to a set of allocations from other
	// lower priority jobs that are preempted. Preempted allocations are marked
	// as stopped.
	NodePreemptions map[string][]*Allocation

	// RefreshIndex is the index the worker should refresh state up to.
	// This allows all evictions and allocations to be materialized.
	// If any allocations were rejected due to stale data (node state,
	// over committed) this can be used to force a worker refresh.
	RefreshIndex uint64

	// AllocIndex is the Raft index in which the evictions and
	// allocations took place. This is used for the write index.
	AllocIndex uint64
}

// IsNoOp checks if this plan result would do nothing
func (p *PlanResult) IsNoOp() bool {
	return len(p.NodeUpdate) == 0 && len(p.NodeAllocation) == 0 &&
		len(p.DeploymentUpdates) == 0 && p.Deployment == nil
}

// FullCommit is used to check if all the allocations in a plan
// were committed as part of the result. Returns if there was
// a match, and the number of expected and actual allocations.
func (p *PlanResult) FullCommit(plan *Plan) (bool, int, int) {
	expected := 0
	actual := 0
	for name, allocList := range plan.NodeAllocation {
		didAlloc, _ := p.NodeAllocation[name]
		expected += len(allocList)
		actual += len(didAlloc)
	}
	return actual == expected, expected, actual
}

// PlanAnnotations holds annotations made by the scheduler to give further debug
// information to operators.
type PlanAnnotations struct {
	// DesiredTGUpdates is the set of desired updates per task group.
	DesiredTGUpdates map[string]*DesiredUpdates

	// PreemptedAllocs is the set of allocations to be preempted to make the placement successful.
	PreemptedAllocs []*AllocListStub
}

// DesiredUpdates is the set of changes the scheduler would like to make given
// sufficient resources and cluster capacity.
type DesiredUpdates struct {
	Ignore            uint64
	Place             uint64
	Migrate           uint64
	Stop              uint64
	InPlaceUpdate     uint64
	DestructiveUpdate uint64
	Canary            uint64
	Preemptions       uint64
}

func (d *DesiredUpdates) GoString() string {
	return fmt.Sprintf("(place %d) (inplace %d) (destructive %d) (stop %d) (migrate %d) (ignore %d) (canary %d)",
		d.Place, d.InPlaceUpdate, d.DestructiveUpdate, d.Stop, d.Migrate, d.Ignore, d.Canary)
}

// msgpackHandle is a shared handle for encoding/decoding of structs
var MsgpackHandle = func() *codec.MsgpackHandle {
	h := &codec.MsgpackHandle{RawToString: true}

	// Sets the default type for decoding a map into a nil interface{}.
	// This is necessary in particular because we store the driver configs as a
	// nil interface{}.
	h.MapType = reflect.TypeOf(map[string]interface{}(nil))
	return h
}()

var (
	// JsonHandle and JsonHandlePretty are the codec handles to JSON encode
	// structs. The pretty handle will add indents for easier human consumption.
	JsonHandle = &codec.JsonHandle{
		HTMLCharsAsIs: true,
	}
	JsonHandlePretty = &codec.JsonHandle{
		HTMLCharsAsIs: true,
		Indent:        4,
	}
)

// TODO Figure out if we can remove this. This is our fork that is just way
// behind. I feel like its original purpose was to pin at a stable version but
// now we can accomplish this with vendoring.
var HashiMsgpackHandle = func() *hcodec.MsgpackHandle {
	h := &hcodec.MsgpackHandle{RawToString: true}

	// Sets the default type for decoding a map into a nil interface{}.
	// This is necessary in particular because we store the driver configs as a
	// nil interface{}.
	h.MapType = reflect.TypeOf(map[string]interface{}(nil))
	return h
}()

// Decode is used to decode a MsgPack encoded object
func Decode(buf []byte, out interface{}) error {
	return codec.NewDecoder(bytes.NewReader(buf), MsgpackHandle).Decode(out)
}

// Encode is used to encode a MsgPack object with type prefix
func Encode(t MessageType, msg interface{}) ([]byte, error) {
	var buf bytes.Buffer
	buf.WriteByte(uint8(t))
	err := codec.NewEncoder(&buf, MsgpackHandle).Encode(msg)
	return buf.Bytes(), err
}

// KeyringResponse is a unified key response and can be used for install,
// remove, use, as well as listing key queries.
type KeyringResponse struct {
	Messages map[string]string
	Keys     map[string]int
	NumNodes int
}

// KeyringRequest is request objects for serf key operations.
type KeyringRequest struct {
	Key string
}

// RecoverableError wraps an error and marks whether it is recoverable and could
// be retried or it is fatal.
type RecoverableError struct {
	Err         string
	Recoverable bool
}

// NewRecoverableError is used to wrap an error and mark it as recoverable or
// not.
func NewRecoverableError(e error, recoverable bool) error {
	if e == nil {
		return nil
	}

	return &RecoverableError{
		Err:         e.Error(),
		Recoverable: recoverable,
	}
}

// WrapRecoverable wraps an existing error in a new RecoverableError with a new
// message. If the error was recoverable before the returned error is as well;
// otherwise it is unrecoverable.
func WrapRecoverable(msg string, err error) error {
	return &RecoverableError{Err: msg, Recoverable: IsRecoverable(err)}
}

func (r *RecoverableError) Error() string {
	return r.Err
}

func (r *RecoverableError) IsRecoverable() bool {
	return r.Recoverable
}

func (r *RecoverableError) IsUnrecoverable() bool {
	return !r.Recoverable
}

// Recoverable is an interface for errors to implement to indicate whether or
// not they are fatal or recoverable.
type Recoverable interface {
	error
	IsRecoverable() bool
}

// IsRecoverable returns true if error is a RecoverableError with
// Recoverable=true. Otherwise false is returned.
func IsRecoverable(e error) bool {
	if re, ok := e.(Recoverable); ok {
		return re.IsRecoverable()
	}
	return false
}

// WrappedServerError wraps an error and satisfies
// both the Recoverable and the ServerSideError interfaces
type WrappedServerError struct {
	Err error
}

// NewWrappedServerError is used to create a wrapped server side error
func NewWrappedServerError(e error) error {
	return &WrappedServerError{
		Err: e,
	}
}

func (r *WrappedServerError) IsRecoverable() bool {
	return IsRecoverable(r.Err)
}

func (r *WrappedServerError) Error() string {
	return r.Err.Error()
}

func (r *WrappedServerError) IsServerSide() bool {
	return true
}

// ServerSideError is an interface for errors to implement to indicate
// errors occurring after the request makes it to a server
type ServerSideError interface {
	error
	IsServerSide() bool
}

// IsServerSide returns true if error is a wrapped
// server side error
func IsServerSide(e error) bool {
	if se, ok := e.(ServerSideError); ok {
		return se.IsServerSide()
	}
	return false
}

// ACLPolicy is used to represent an ACL policy
type ACLPolicy struct {
	Name        string // Unique name
	Description string // Human readable
	Rules       string // HCL or JSON format
	Hash        []byte
	CreateIndex uint64
	ModifyIndex uint64
}

// SetHash is used to compute and set the hash of the ACL policy
func (c *ACLPolicy) SetHash() []byte {
	// Initialize a 256bit Blake2 hash (32 bytes)
	hash, err := blake2b.New256(nil)
	if err != nil {
		panic(err)
	}

	// Write all the user set fields
	hash.Write([]byte(c.Name))
	hash.Write([]byte(c.Description))
	hash.Write([]byte(c.Rules))

	// Finalize the hash
	hashVal := hash.Sum(nil)

	// Set and return the hash
	c.Hash = hashVal
	return hashVal
}

func (a *ACLPolicy) Stub() *ACLPolicyListStub {
	return &ACLPolicyListStub{
		Name:        a.Name,
		Description: a.Description,
		Hash:        a.Hash,
		CreateIndex: a.CreateIndex,
		ModifyIndex: a.ModifyIndex,
	}
}

func (a *ACLPolicy) Validate() error {
	var mErr multierror.Error
	if !validPolicyName.MatchString(a.Name) {
		err := fmt.Errorf("invalid name '%s'", a.Name)
		mErr.Errors = append(mErr.Errors, err)
	}
	if _, err := acl.Parse(a.Rules); err != nil {
		err = fmt.Errorf("failed to parse rules: %v", err)
		mErr.Errors = append(mErr.Errors, err)
	}
	if len(a.Description) > maxPolicyDescriptionLength {
		err := fmt.Errorf("description longer than %d", maxPolicyDescriptionLength)
		mErr.Errors = append(mErr.Errors, err)
	}
	return mErr.ErrorOrNil()
}

// ACLPolicyListStub is used to for listing ACL policies
type ACLPolicyListStub struct {
	Name        string
	Description string
	Hash        []byte
	CreateIndex uint64
	ModifyIndex uint64
}

// ACLPolicyListRequest is used to request a list of policies
type ACLPolicyListRequest struct {
	QueryOptions
}

// ACLPolicySpecificRequest is used to query a specific policy
type ACLPolicySpecificRequest struct {
	Name string
	QueryOptions
}

// ACLPolicySetRequest is used to query a set of policies
type ACLPolicySetRequest struct {
	Names []string
	QueryOptions
}

// ACLPolicyListResponse is used for a list request
type ACLPolicyListResponse struct {
	Policies []*ACLPolicyListStub
	QueryMeta
}

// SingleACLPolicyResponse is used to return a single policy
type SingleACLPolicyResponse struct {
	Policy *ACLPolicy
	QueryMeta
}

// ACLPolicySetResponse is used to return a set of policies
type ACLPolicySetResponse struct {
	Policies map[string]*ACLPolicy
	QueryMeta
}

// ACLPolicyDeleteRequest is used to delete a set of policies
type ACLPolicyDeleteRequest struct {
	Names []string
	WriteRequest
}

// ACLPolicyUpsertRequest is used to upsert a set of policies
type ACLPolicyUpsertRequest struct {
	Policies []*ACLPolicy
	WriteRequest
}

// ACLToken represents a client token which is used to Authenticate
type ACLToken struct {
	AccessorID  string   // Public Accessor ID (UUID)
	SecretID    string   // Secret ID, private (UUID)
	Name        string   // Human friendly name
	Type        string   // Client or Management
	Policies    []string // Policies this token ties to
	Global      bool     // Global or Region local
	Hash        []byte
	CreateTime  time.Time // Time of creation
	CreateIndex uint64
	ModifyIndex uint64
}

var (
	// AnonymousACLToken is used no SecretID is provided, and the
	// request is made anonymously.
	AnonymousACLToken = &ACLToken{
		AccessorID: "anonymous",
		Name:       "Anonymous Token",
		Type:       ACLClientToken,
		Policies:   []string{"anonymous"},
		Global:     false,
	}
)

type ACLTokenListStub struct {
	AccessorID  string
	Name        string
	Type        string
	Policies    []string
	Global      bool
	Hash        []byte
	CreateTime  time.Time
	CreateIndex uint64
	ModifyIndex uint64
}

// SetHash is used to compute and set the hash of the ACL token
func (a *ACLToken) SetHash() []byte {
	// Initialize a 256bit Blake2 hash (32 bytes)
	hash, err := blake2b.New256(nil)
	if err != nil {
		panic(err)
	}

	// Write all the user set fields
	hash.Write([]byte(a.Name))
	hash.Write([]byte(a.Type))
	for _, policyName := range a.Policies {
		hash.Write([]byte(policyName))
	}
	if a.Global {
		hash.Write([]byte("global"))
	} else {
		hash.Write([]byte("local"))
	}

	// Finalize the hash
	hashVal := hash.Sum(nil)

	// Set and return the hash
	a.Hash = hashVal
	return hashVal
}

func (a *ACLToken) Stub() *ACLTokenListStub {
	return &ACLTokenListStub{
		AccessorID:  a.AccessorID,
		Name:        a.Name,
		Type:        a.Type,
		Policies:    a.Policies,
		Global:      a.Global,
		Hash:        a.Hash,
		CreateTime:  a.CreateTime,
		CreateIndex: a.CreateIndex,
		ModifyIndex: a.ModifyIndex,
	}
}

// Validate is used to sanity check a token
func (a *ACLToken) Validate() error {
	var mErr multierror.Error
	if len(a.Name) > maxTokenNameLength {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("token name too long"))
	}
	switch a.Type {
	case ACLClientToken:
		if len(a.Policies) == 0 {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("client token missing policies"))
		}
	case ACLManagementToken:
		if len(a.Policies) != 0 {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("management token cannot be associated with policies"))
		}
	default:
		mErr.Errors = append(mErr.Errors, fmt.Errorf("token type must be client or management"))
	}
	return mErr.ErrorOrNil()
}

// PolicySubset checks if a given set of policies is a subset of the token
func (a *ACLToken) PolicySubset(policies []string) bool {
	// Hot-path the management tokens, superset of all policies.
	if a.Type == ACLManagementToken {
		return true
	}
	associatedPolicies := make(map[string]struct{}, len(a.Policies))
	for _, policy := range a.Policies {
		associatedPolicies[policy] = struct{}{}
	}
	for _, policy := range policies {
		if _, ok := associatedPolicies[policy]; !ok {
			return false
		}
	}
	return true
}

// ACLTokenListRequest is used to request a list of tokens
type ACLTokenListRequest struct {
	GlobalOnly bool
	QueryOptions
}

// ACLTokenSpecificRequest is used to query a specific token
type ACLTokenSpecificRequest struct {
	AccessorID string
	QueryOptions
}

// ACLTokenSetRequest is used to query a set of tokens
type ACLTokenSetRequest struct {
	AccessorIDS []string
	QueryOptions
}

// ACLTokenListResponse is used for a list request
type ACLTokenListResponse struct {
	Tokens []*ACLTokenListStub
	QueryMeta
}

// SingleACLTokenResponse is used to return a single token
type SingleACLTokenResponse struct {
	Token *ACLToken
	QueryMeta
}

// ACLTokenSetResponse is used to return a set of token
type ACLTokenSetResponse struct {
	Tokens map[string]*ACLToken // Keyed by Accessor ID
	QueryMeta
}

// ResolveACLTokenRequest is used to resolve a specific token
type ResolveACLTokenRequest struct {
	SecretID string
	QueryOptions
}

// ResolveACLTokenResponse is used to resolve a single token
type ResolveACLTokenResponse struct {
	Token *ACLToken
	QueryMeta
}

// ACLTokenDeleteRequest is used to delete a set of tokens
type ACLTokenDeleteRequest struct {
	AccessorIDs []string
	WriteRequest
}

// ACLTokenBootstrapRequest is used to bootstrap ACLs
type ACLTokenBootstrapRequest struct {
	Token      *ACLToken // Not client specifiable
	ResetIndex uint64    // Reset index is used to clear the bootstrap token
	WriteRequest
}

// ACLTokenUpsertRequest is used to upsert a set of tokens
type ACLTokenUpsertRequest struct {
	Tokens []*ACLToken
	WriteRequest
}

// ACLTokenUpsertResponse is used to return from an ACLTokenUpsertRequest
type ACLTokenUpsertResponse struct {
	Tokens []*ACLToken
	WriteMeta
}