Google Pub/Sub Publisher sample in Golang

main.go

package main

import (
	"context"
	"fmt"
	"io/ioutil"
	"log"

	"google.golang.org/api/option"

	"golang.org/x/oauth2/google"

	"cloud.google.com/go/pubsub"
)

const (
	credentialJSONPath = ""
	projectID          = ""
	topicName          = ""
)

func main() {
	jsonKey, err := ioutil.ReadFile(credentialJSONPath)
	conf, err := google.JWTConfigFromJSON(jsonKey, pubsub.ScopePubSub, pubsub.ScopeCloudPlatform)
	if err != nil {
		log.Fatal(err)
	}
	ctx := context.Background()
	ts := conf.TokenSource(ctx)
	c, err := pubsub.NewClient(ctx, projectID, option.WithTokenSource(ts))
	if err != nil {
		log.Fatal("new client:", err)
	}
	topic := c.Topic(topicName)
	defer topic.Stop()

	var results []*pubsub.PublishResult
	r := topic.Publish(ctx, &pubsub.Message{
		Data: []byte("hello world"),
	})
	results = append(results, r)
	for _, r := range results {
		id, err := r.Get(ctx)
		if err != nil {
			fmt.Println(err)
		}
		fmt.Printf("Published a message with a message ID: %s\n", id)
	}
}