clustername.go

/*
Copyright 2017 Gravitational, Inc.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package services

import (
	"encoding/json"
	"fmt"
	"time"

	"github.com/gravitational/teleport/lib/defaults"
	"github.com/gravitational/teleport/lib/utils"

	"github.com/gravitational/trace"
	"github.com/jonboulle/clockwork"
)

// ClusterName defines the name of the cluster. This is a configuration
// resource, never create more than one instance of it.
type ClusterName interface {
	// Resource provides common resource properties.
	Resource

	// SetClusterName sets the name of the cluster.
	SetClusterName(string)
	// GetClusterName gets the name of the cluster.
	GetClusterName() string

	// CheckAndSetDefaults checks and set default values for missing fields.
	CheckAndSetDefaults() error
}

// NewClusterName is a convenience wrapper to create a ClusterName resource.
func NewClusterName(spec ClusterNameSpecV2) (ClusterName, error) {
	cn := ClusterNameV2{
		Kind:    KindClusterName,
		Version: V2,
		Metadata: Metadata{
			Name:      MetaNameClusterName,
			Namespace: defaults.Namespace,
		},
		Spec: spec,
	}
	if err := cn.CheckAndSetDefaults(); err != nil {
		return nil, trace.Wrap(err)
	}

	return &cn, nil
}

// ClusterNameV2 implements the ClusterName interface.
type ClusterNameV2 struct {
	// Kind is a resource kind - always resource.
	Kind string `json:"kind"`

	// Version is a resource version.
	Version string `json:"version"`

	// Metadata is metadata about the resource.
	Metadata Metadata `json:"metadata"`

	// Spec is the specification of the resource.
	Spec ClusterNameSpecV2 `json:"spec"`
}

// ClusterNameSpecV2 is the actual data we care about for ClusterName.
type ClusterNameSpecV2 struct {
	// ClusterName is the name of the cluster. Changing this value once the
	// cluster is setup can and will cause catastrophic problems.
	ClusterName string `json:"cluster_name"`
}

// GetName returns the name of the cluster.
func (c *ClusterNameV2) GetName() string {
	return c.Metadata.Name
}

// SetName sets the name of the cluster.
func (c *ClusterNameV2) SetName(e string) {
	c.Metadata.Name = e
}

// Expires returns object expiry setting
func (c *ClusterNameV2) Expiry() time.Time {
	return c.Metadata.Expiry()
}

// SetExpiry sets expiry time for the object
func (c *ClusterNameV2) SetExpiry(expires time.Time) {
	c.Metadata.SetExpiry(expires)
}

// SetTTL sets Expires header using realtime clock
func (c *ClusterNameV2) SetTTL(clock clockwork.Clock, ttl time.Duration) {
	c.Metadata.SetTTL(clock, ttl)
}

// GetMetadata returns object metadata
func (c *ClusterNameV2) GetMetadata() Metadata {
	return c.Metadata
}

// SetClusterName sets the name of the cluster.
func (c *ClusterNameV2) SetClusterName(n string) {
	c.Spec.ClusterName = n
}

// GetClusterName gets the name of the cluster.
func (c *ClusterNameV2) GetClusterName() string {
	return c.Spec.ClusterName
}

// CheckAndSetDefaults checks validity of all parameters and sets defaults.
func (c *ClusterNameV2) CheckAndSetDefaults() error {
	// make sure we have defaults for all metadata fields
	err := c.Metadata.CheckAndSetDefaults()
	if err != nil {
		return trace.Wrap(err)
	}

	if c.Spec.ClusterName == "" {
		return trace.BadParameter("cluster name is required")
	}

	return nil
}

// String represents a human readable version of the cluster name.
func (c *ClusterNameV2) String() string {
	return fmt.Sprintf("ClusterName(%v)", c.Spec.ClusterName)
}

// ClusterNameSpecSchemaTemplate is a template for ClusterName schema.
const ClusterNameSpecSchemaTemplate = `{
  "type": "object",
  "additionalProperties": false,
  "properties": {
    "cluster_name": {
      "type": "string"
    }%v
  }
}`

// GetClusterNameSchema returns the schema with optionally injected
// schema for extensions.
func GetClusterNameSchema(extensionSchema string) string {
	var clusterNameSchema string
	if clusterNameSchema == "" {
		clusterNameSchema = fmt.Sprintf(ClusterNameSpecSchemaTemplate, "")
	} else {
		clusterNameSchema = fmt.Sprintf(ClusterNameSpecSchemaTemplate, ","+extensionSchema)
	}
	return fmt.Sprintf(V2SchemaTemplate, MetadataSchema, clusterNameSchema, DefaultDefinitions)
}

// ClusterNameMarshaler implements marshal/unmarshal of ClusterName implementations
// mostly adds support for extended versions.
type ClusterNameMarshaler interface {
	Marshal(c ClusterName, opts ...MarshalOption) ([]byte, error)
	Unmarshal(bytes []byte) (ClusterName, error)
}

var clusterNameMarshaler ClusterNameMarshaler = &TeleportClusterNameMarshaler{}

// SetClusterNameMarshaler sets the marshaler.
func SetClusterNameMarshaler(m ClusterNameMarshaler) {
	marshalerMutex.Lock()
	defer marshalerMutex.Unlock()
	clusterNameMarshaler = m
}

// GetClusterNameMarshaler gets the marshaler.
func GetClusterNameMarshaler() ClusterNameMarshaler {
	marshalerMutex.Lock()
	defer marshalerMutex.Unlock()
	return clusterNameMarshaler
}

// TeleportClusterNameMarshaler is used to marshal and unmarshal ClusterName.
type TeleportClusterNameMarshaler struct{}

// Unmarshal unmarshals ClusterName from JSON.
func (t *TeleportClusterNameMarshaler) Unmarshal(bytes []byte) (ClusterName, error) {
	var clusterName ClusterNameV2

	if len(bytes) == 0 {
		return nil, trace.BadParameter("missing resource data")
	}

	err := utils.UnmarshalWithSchema(GetClusterNameSchema(""), &clusterName, bytes)
	if err != nil {
		return nil, trace.BadParameter(err.Error())
	}

	err = clusterName.CheckAndSetDefaults()
	if err != nil {
		return nil, trace.Wrap(err)
	}

	return &clusterName, nil
}

// Marshal marshals ClusterName to JSON.
func (t *TeleportClusterNameMarshaler) Marshal(c ClusterName, opts ...MarshalOption) ([]byte, error) {
	return json.Marshal(c)
}