awsparamstore

Documentation

Overview

Package awsparamstore provides a runtimevar implementation with variables read from AWS Systems Manager Parameter Store (https://docs.aws.amazon.com/systems-manager/latest/userguide/systems-manager-paramstore.html) Use OpenVariable to construct a *runtimevar.Variable.

URLs

For runtimevar.OpenVariable, awsparamstore registers for the scheme "awsparamstore". The default URL opener will use an AWS session with the default credentials and configuration; see https://docs.aws.amazon.com/sdk-for-go/api/aws/session/ for more details. 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

awsparamstore exposes the following types for As:

• Snapshot: *ssm.GetParameterOutput, *ssm.DescribeParametersOutput
• Error: awserr.Error

Example

package main

import (
	"context"
	"log"

	"github.com/aws/aws-sdk-go/aws/session"
	"github.com/eliben/gocdkx/runtimevar"
	"github.com/eliben/gocdkx/runtimevar/awsparamstore"
)

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

func main() {
	// Establish an AWS session.
	// See https://docs.aws.amazon.com/sdk-for-go/api/aws/session/ for more info.
	sess, err := session.NewSession(nil)
	if err != nil {
		log.Fatal(err)
	}

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

	// Construct a *runtimevar.Variable that watches the variable.
	// For this example, the Parameter Store variable being referenced
	// should have a JSON string that decodes into MyConfig.
	v, err := awsparamstore.OpenVariable(sess, "cfg-variable-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, "awsparamstore://myvar?region=us-west-1")
	if err != nil {
		log.Fatal(err)
	}

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

Index

• Constants
• Variables
• func OpenVariable(sess client.ConfigProvider, name string, decoder *runtimevar.Decoder, ...) (*runtimevar.Variable, error)
• type Options
• type URLOpener
  • func (o *URLOpener) OpenVariableURL(ctx context.Context, u *url.URL) (*runtimevar.Variable, error)

Examples

• Package
• Package (OpenVariable)

Constants

const Scheme = "awsparamstore"

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

Variables

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

Set holds Wire providers for this package.

Functions

func OpenVariable

func OpenVariable(sess client.ConfigProvider, name string, decoder *runtimevar.Decoder, opts *Options) (*runtimevar.Variable, error)

OpenVariable constructs a *runtimevar.Variable backed by the variable name in AWS Systems Manager Parameter Store. Parameter Store 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 URLOpener

type URLOpener struct {
	// ConfigProvider must be set to a non-nil value.
	ConfigProvider client.ConfigProvider

	// 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 AWS Paramstore URLs like "awsparamstore://myvar". See github.com/eliben/gocdkx/aws/ConfigFromURLParams for supported query parameters that affect the default AWS session.

In addition, the following URL 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 the variable at the URL's path. See the package doc for more details.