paramstore

package main

import (
	"context"
	"log"

	"github.com/aws/aws-sdk-go/aws/session"
	"gocloud.dev/runtimevar"
	"gocloud.dev/runtimevar/paramstore"
)

// 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.
	session, 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 := paramstore.NewVariable(session, "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.Watch(context.Background())
	if err != nil {
		log.Fatal(err)
	}
	cfg := snapshot.Value.(MyConfig)
	_ = cfg
}

Output: