forked from hashicorp/nomad
/
util.go
396 lines (342 loc) · 8.75 KB
/
util.go
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package nomad
import (
"fmt"
"math/rand"
"net"
"os"
"path/filepath"
"strconv"
memdb "github.com/hashicorp/go-memdb"
version "github.com/hashicorp/go-version"
"github.com/hashicorp/nomad/nomad/state"
"github.com/hashicorp/nomad/nomad/structs"
"github.com/hashicorp/serf/serf"
)
// MinVersionPlanNormalization is the minimum version to support the
// normalization of Plan in SubmitPlan, and the denormalization raft log entry committed
// in ApplyPlanResultsRequest
var MinVersionPlanNormalization = version.Must(version.NewVersion("0.9.2"))
// ensurePath is used to make sure a path exists
func ensurePath(path string, dir bool) error {
if !dir {
path = filepath.Dir(path)
}
return os.MkdirAll(path, 0755)
}
// serverParts is used to return the parts of a server role
type serverParts struct {
Name string
ID string
Region string
Datacenter string
Port int
Bootstrap bool
Expect int
MajorVersion int
MinorVersion int
Build version.Version
RaftVersion int
Addr net.Addr
RPCAddr net.Addr
Status serf.MemberStatus
NonVoter bool
}
func (s *serverParts) String() string {
return fmt.Sprintf("%s (Addr: %s) (DC: %s)",
s.Name, s.Addr, s.Datacenter)
}
func (s *serverParts) Copy() *serverParts {
ns := new(serverParts)
*ns = *s
return ns
}
// Returns if a member is a Nomad server. Returns a boolean,
// and a struct with the various important components
func isNomadServer(m serf.Member) (bool, *serverParts) {
if m.Tags["role"] != "nomad" {
return false, nil
}
id := "unknown"
if v, ok := m.Tags["id"]; ok {
id = v
}
region := m.Tags["region"]
datacenter := m.Tags["dc"]
_, bootstrap := m.Tags["bootstrap"]
expect := 0
expectStr, ok := m.Tags["expect"]
var err error
if ok {
expect, err = strconv.Atoi(expectStr)
if err != nil {
return false, nil
}
}
// If the server is missing the rpc_addr tag, default to the serf advertise addr
rpcIP := net.ParseIP(m.Tags["rpc_addr"])
if rpcIP == nil {
rpcIP = m.Addr
}
portStr := m.Tags["port"]
port, err := strconv.Atoi(portStr)
if err != nil {
return false, nil
}
buildVersion, err := version.NewVersion(m.Tags["build"])
if err != nil {
return false, nil
}
// The "vsn" tag was Version, which is now the MajorVersion number.
majorVersionStr := m.Tags["vsn"]
majorVersion, err := strconv.Atoi(majorVersionStr)
if err != nil {
return false, nil
}
// To keep some semblance of convention, "mvn" is now the "Minor
// Version Number."
minorVersionStr := m.Tags["mvn"]
minorVersion, err := strconv.Atoi(minorVersionStr)
if err != nil {
minorVersion = 0
}
raftVsn := 0
raftVsnString, ok := m.Tags["raft_vsn"]
if ok {
raftVsn, err = strconv.Atoi(raftVsnString)
if err != nil {
return false, nil
}
}
// Check if the server is a non voter
_, nonVoter := m.Tags["nonvoter"]
addr := &net.TCPAddr{IP: m.Addr, Port: port}
rpcAddr := &net.TCPAddr{IP: rpcIP, Port: port}
parts := &serverParts{
Name: m.Name,
ID: id,
Region: region,
Datacenter: datacenter,
Port: port,
Bootstrap: bootstrap,
Expect: expect,
Addr: addr,
RPCAddr: rpcAddr,
MajorVersion: majorVersion,
MinorVersion: minorVersion,
Build: *buildVersion,
RaftVersion: raftVsn,
Status: m.Status,
NonVoter: nonVoter,
}
return true, parts
}
// ServersMeetMinimumVersion returns whether the Nomad servers are at least on the
// given Nomad version. The checkFailedServers parameter specifies whether version
// for the failed servers should be verified.
func ServersMeetMinimumVersion(members []serf.Member, minVersion *version.Version, checkFailedServers bool) bool {
for _, member := range members {
if valid, parts := isNomadServer(member); valid && (parts.Status == serf.StatusAlive || (checkFailedServers && parts.Status == serf.StatusFailed)) {
// Check if the versions match - version.LessThan will return true for
// 0.8.0-rc1 < 0.8.0, so we want to ignore the metadata
versionsMatch := slicesMatch(minVersion.Segments(), parts.Build.Segments())
if parts.Build.LessThan(minVersion) && !versionsMatch {
return false
}
}
}
return true
}
func slicesMatch(a, b []int) bool {
if a == nil && b == nil {
return true
}
if a == nil || b == nil {
return false
}
if len(a) != len(b) {
return false
}
for i := range a {
if a[i] != b[i] {
return false
}
}
return true
}
// shuffleStrings randomly shuffles the list of strings
func shuffleStrings(list []string) {
for i := range list {
j := rand.Intn(i + 1)
list[i], list[j] = list[j], list[i]
}
}
// partitionAll splits a slice of strings into a slice of slices of strings, each with a max
// size of `size`. All entries from the original slice are preserved. The last slice may be
// smaller than `size`. The input slice is unmodified
func partitionAll(size int, xs []string) [][]string {
if size < 1 {
return [][]string{xs}
}
out := [][]string{}
for i := 0; i < len(xs); i += size {
j := i + size
if j > len(xs) {
j = len(xs)
}
out = append(out, xs[i:j])
}
return out
}
// maxUint64 returns the maximum value
func maxUint64(inputs ...uint64) uint64 {
l := len(inputs)
if l == 0 {
return 0
} else if l == 1 {
return inputs[0]
}
max := inputs[0]
for i := 1; i < l; i++ {
cur := inputs[i]
if cur > max {
max = cur
}
}
return max
}
// getNodeForRpc returns a Node struct if the Node supports Node RPC. Otherwise
// an error is returned.
func getNodeForRpc(snap *state.StateSnapshot, nodeID string) (*structs.Node, error) {
node, err := snap.NodeByID(nil, nodeID)
if err != nil {
return nil, err
}
if node == nil {
return nil, fmt.Errorf("Unknown node %q", nodeID)
}
if err := nodeSupportsRpc(node); err != nil {
return nil, err
}
return node, nil
}
var minNodeVersionSupportingRPC = version.Must(version.NewVersion("0.8.0-rc1"))
// nodeSupportsRpc returns a non-nil error if a Node does not support RPC.
func nodeSupportsRpc(node *structs.Node) error {
rawNodeVer, ok := node.Attributes["nomad.version"]
if !ok {
return structs.ErrUnknownNomadVersion
}
nodeVer, err := version.NewVersion(rawNodeVer)
if err != nil {
return structs.ErrUnknownNomadVersion
}
if nodeVer.LessThan(minNodeVersionSupportingRPC) {
return structs.ErrNodeLacksRpc
}
return nil
}
// AllocGetter is an interface for retrieving allocations by ID. It is
// satisfied by *state.StateStore and *state.StateSnapshot.
type AllocGetter interface {
AllocByID(ws memdb.WatchSet, id string) (*structs.Allocation, error)
}
// getAlloc retrieves an allocation by ID and namespace. If the allocation is
// nil, an error is returned.
func getAlloc(state AllocGetter, allocID string) (*structs.Allocation, error) {
if allocID == "" {
return nil, structs.ErrMissingAllocID
}
alloc, err := state.AllocByID(nil, allocID)
if err != nil {
return nil, err
}
if alloc == nil {
return nil, structs.NewErrUnknownAllocation(allocID)
}
return alloc, nil
}
// dropButLastChannel returns a channel that drops all but last value from sourceCh.
//
// Useful for aggressively consuming sourceCh when intermediate values aren't relevant.
//
// This function propagates values to result quickly and drops intermediate messages
// in best effort basis. Golang scheduler may delay delivery or result in extra
// deliveries.
//
// Consider this function for example:
//
// ```
// src := make(chan bool)
// dst := dropButLastChannel(src, nil)
//
// go func() {
// src <- true
// src <- false
// }()
//
// // v can be `true` here but is very unlikely
// v := <-dst
// ```
//
func dropButLastChannel(sourceCh <-chan bool, shutdownCh <-chan struct{}) chan bool {
// buffer the most recent result
dst := make(chan bool)
go func() {
// last value received
lv := false
// ok source was closed
ok := false
// received message since last delivery to destination
messageReceived := false
DEQUE_SOURCE:
// wait for first message
select {
case lv, ok = <-sourceCh:
if !ok {
goto SOURCE_CLOSED
}
messageReceived = true
goto ENQUEUE_DST
case <-shutdownCh:
return
}
ENQUEUE_DST:
// prioritize draining source first dequeue without blocking
for {
select {
case lv, ok = <-sourceCh:
if !ok {
goto SOURCE_CLOSED
}
messageReceived = true
default:
break ENQUEUE_DST
}
}
// attempt to enqueue but keep monitoring source channel
select {
case lv, ok = <-sourceCh:
if !ok {
goto SOURCE_CLOSED
}
messageReceived = true
goto ENQUEUE_DST
case dst <- lv:
messageReceived = false
// enqueued value; back to dequeing from source
goto DEQUE_SOURCE
case <-shutdownCh:
return
}
SOURCE_CLOSED:
if messageReceived {
select {
case dst <- lv:
case <-shutdownCh:
return
}
}
close(dst)
}()
return dst
}