gcpruntimeconfig

Documentation

Overview

Package gcpruntimeconfig provides a runtimevar implementation with variables read from GCP Cloud Runtime Configurator (https://cloud.google.com/deployment-manager/runtime-configurator). Use OpenVariable to construct a *runtimevar.Variable.

URLs

For runtimevar.OpenVariable, gcpruntimeconfig registers for the scheme "gcpruntimeconfig". The default URL opener will creating a connection using use default credentials from the environment, as described in https://cloud.google.com/docs/authentication/production. To customize the URL opener, or for more details on the URL format, see URLOpener. See https://github.com/eliben/gocdkx/concepts/urls/ for background information.

As

gcpruntimeconfig exposes the following types for As:

• Snapshot: *pb.Variable
• Error: *status.Status

Example

package main

import (
	"context"
	"log"

	"github.com/eliben/gocdkx/gcp"
	"github.com/eliben/gocdkx/runtimevar"
	"github.com/eliben/gocdkx/runtimevar/gcpruntimeconfig"
)

// MyConfig is a sample configuration struct.
type MyConfig struct {
	Server string
	Port   int
}

func main() {
	// Your GCP credentials.
	// See https://cloud.google.com/docs/authentication/production
	// for more info on alternatives.
	ctx := context.Background()
	creds, err := gcp.DefaultCredentials(ctx)
	if err != nil {
		log.Fatal(err)
	}

	// Connect to the Runtime Configurator service.
	client, cleanup, err := gcpruntimeconfig.Dial(ctx, creds.TokenSource)
	if err != nil {
		log.Fatal(err)
	}
	defer cleanup()

	// Create a decoder for decoding JSON strings into MyConfig.
	decoder := runtimevar.NewDecoder(MyConfig{}, runtimevar.JSONDecode)

	// Fill these in with the values from the Cloud Console.
	// For this example, the GCP Cloud Runtime Configurator variable being
	// referenced should have a JSON string that decodes into MyConfig.
	name := gcpruntimeconfig.ResourceName{
		ProjectID: "gcp-project-id",
		Config:    "cfg-name",
		Variable:  "cfg-variable-name",
	}

	// Construct a *runtimevar.Variable that watches the variable.
	v, err := gcpruntimeconfig.OpenVariable(client, name, decoder, nil)
	if err != nil {
		log.Fatal(err)
	}
	defer v.Close()

	// We can now read the current value of the variable from v.
	snapshot, err := v.Latest(context.Background())
	if err != nil {
		log.Fatal(err)
	}
	cfg := snapshot.Value.(MyConfig)
	_ = cfg
}

Example (OpenVariable)

package main

import (
	"context"
	"log"

	"github.com/eliben/gocdkx/runtimevar"
)

func main() {
	// OpenVariable creates a *runtimevar.Variable from a URL.
	ctx := context.Background()
	v, err := runtimevar.OpenVariable(ctx, "gcpruntimeconfig://myproject/myconfigid/myvar?decoder=string")
	if err != nil {
		log.Fatal(err)
	}

	snapshot, err := v.Latest(ctx)
	_, _ = snapshot, err
}

Index

• Constants
• Variables
• func Dial(ctx context.Context, ts gcp.TokenSource) (pb.RuntimeConfigManagerClient, func(), error)
• func OpenVariable(client pb.RuntimeConfigManagerClient, name ResourceName, ...) (*runtimevar.Variable, error)
• type Options
• type ResourceName
  • func (r ResourceName) String() string
• type URLOpener
  • func (o *URLOpener) OpenVariableURL(ctx context.Context, u *url.URL) (*runtimevar.Variable, error)

Examples

• Package
• Package (OpenVariable)

Constants

const Scheme = "gcpruntimeconfig"

Scheme is the URL scheme gcpruntimeconfig registers its URLOpener under on runtimevar.DefaultMux.

Variables

var Set = wire.NewSet(
	Dial,
	URLOpener{},
)

Set holds Wire providers for this package.

Functions

func Dial

func Dial(ctx context.Context, ts gcp.TokenSource) (pb.RuntimeConfigManagerClient, func(), error)

Dial opens a gRPC connection to the Runtime Configurator API using credentials from ts. It is provided as an optional helper with useful defaults.

The second return value is a function that should be called to clean up the connection opened by Dial.

func OpenVariable

func OpenVariable(client pb.RuntimeConfigManagerClient, name ResourceName, decoder *runtimevar.Decoder, opts *Options) (*runtimevar.Variable, error)

OpenVariable constructs a *runtimevar.Variable backed by the variable name in GCP Cloud Runtime Configurator. Runtime Configurator returns raw bytes; provide a decoder to decode the raw bytes into the appropriate type for runtimevar.Snapshot.Value. See the runtimevar package documentation for examples of decoders.

Types

type Options

type Options struct {
	// WaitDuration controls the rate at which Parameter Store is polled.
	// Defaults to 30 seconds.
	WaitDuration time.Duration
}

Options sets options.

type ResourceName

type ResourceName struct {
	ProjectID string
	Config    string
	Variable  string
}

ResourceName identifies a configuration variable.

func (ResourceName) String

func (r ResourceName) String() string

String returns the full configuration variable path.

type URLOpener

type URLOpener struct {
	// Client must be set to a non-nil client authenticated with
	// Cloud RuntimeConfigurator scope or equivalent.
	Client pb.RuntimeConfigManagerClient

	// Decoder specifies the decoder to use if one is not specified in the URL.
	// Defaults to runtimevar.BytesDecoder.
	Decoder *runtimevar.Decoder

	// Options specifies the options to pass to New.
	Options Options
}

URLOpener opens gcpruntimeconfig URLs like "gcpruntimeconfig://myproject/mycfg/myvar".

• The URL's host holds the GCP projectID.
• The first element of the URL's path holds the GCP RuntimeConfigurator ConfigID.
• The second element of the URL's path holds the GCP RuntimeConfigurator Variable Name.

See https://cloud.google.com/deployment-manager/runtime-configurator/ for more details.

The following query parameters are supported:

• decoder: The decoder to use. Defaults to URLOpener.Decoder, or runtimevar.BytesDecoder if URLOpener.Decoder is nil. See runtimevar.DecoderByName for supported values.

func (*URLOpener) OpenVariableURL

func (o *URLOpener) OpenVariableURL(ctx context.Context, u *url.URL) (*runtimevar.Variable, error)

OpenVariableURL opens a gcpruntimeconfig Variable for u.