google pubsub golang pull example

google pubsub golang pull example

package main

import (
	"golang.org/x/oauth2"
	"golang.org/x/oauth2/google"
	"google.golang.org/cloud"
	"google.golang.org/cloud/pubsub"
	"io/ioutil"
	"log"
)

func main() {
	jsonKey, err := ioutil.ReadFile("pubsub-key.json")
	if err != nil {
		log.Fatal(err)
	}
	conf, err := google.JWTConfigFromJSON(
		jsonKey,
		pubsub.ScopeCloudPlatform,
		pubsub.ScopePubSub,
	)
	if err != nil {
		log.Fatal(err)
	}
	ctx := cloud.NewContext("xxx", conf.Client(oauth2.NoContext))

	msgIDs, err := pubsub.Publish(ctx, "topic1", &pubsub.Message{
		Data: []byte("hello world"),
	})

	if err != nil {
		log.Println(err)
	}

	log.Printf("Published a message with a message id: %s\n", msgIDs[0])

	for {
		msgs, err := pubsub.Pull(ctx, "subscription1", 1)
		if err != nil {
			log.Println(err)
		}

		if len(msgs) > 0 {
			log.Printf("New message arrived: %v, len: %d\n", msgs[0].ID, len(msgs))
			if err := pubsub.Ack(ctx, "subscription1", msgs[0].AckID); err != nil {
				log.Fatal(err)
			}
			log.Println("Acknowledged message")
			log.Printf("Message: %s", msgs[0].Data)
		}
	}
}