Google Cloud Pubsub example

1-pubsub-setup.js

const {PubSub} = require('@google-cloud/pubsub');

const pubsub = new PubSub({
  projectId: 'some-project',
  //apiEndpoint: 'localhost:8085' // for local emulator
});

const topicName = 'sometopic';
const subscriptionName = 'somesub';

pubsub.topic(topicName).createSubscription(subscriptionName);
pubsub.createTopic(topicName)
  .then(() => {
    console.log(`Subscription ${subscriptionName} created.`);
  })
  .then(() => {
    pubsub.topic(topicName).createSubscription(subscriptionName);
  })
  .catch((err) => {
    console.log(`Failed to create subscription: ${subscriptionName}. err: ${err}`);
  });

2-listener.js

const {PubSub} = require('@google-cloud/pubsub');

const pubsub = new PubSub({
  projectId: 'some-project',
  //apiEndpoint: 'localhost:8085' // for local emulator
});

const timeout = 600;
const subscriptionName = 'somesub';
const subscription = pubsub.subscription(subscriptionName);
let messageCount = 0;
const messageHandler = message => {
  console.log('Received message', message.id);
  console.log('\tData:',message.data);
  console.log('\tData string:', message.data.toString());
  console.log('\tAttributes:', message.attributes);
  messageCount += 1;
  message.ack();
};
subscription.on(`message`, messageHandler);

setTimeout(() => {
  subscription.removeListener('message', messageHandler);
  console.log(`${messageCount} message(s) received.`);
}, timeout * 1000);

3-publisher.js

const {PubSub} = require('@google-cloud/pubsub');

const pubsub = new PubSub({
  projectId: 'some-project',
  //apiEndpoint: 'localhost:8085' // for local emulator
});

 const topicName = 'sometopic';
 const data = JSON.stringify({ foo: 'bar' });

const dataBuffer = Buffer.from(data);

pubsub.topic(topicName).publish(dataBuffer).
  then((messageId) => {
    console.log(`Message ${messageId} published.`);
  });