Simple publish / subscribe Google Cloud Functions

package.json

{
  "name": "nodejs-functions-pubsub",
  "version": "0.0.1",
  "dependencies": {
    "@google-cloud/pubsub": "0.22.2",
    "@google-cloud/logging": "^4.2.0"
  }
}

publish.js

'use strict';

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

const pubsub = new PubSub();
const logging = new Logging();

exports.publish = (req, res) => {
  
  const random = Math.random();
  
  // Uncomment for custom logging
  const log = logging.log("my-log");
  const entry = log.entry({resource: {
    type: 'global',
    labels: {
      project_id: process.env.GCLOUD_PROJECT,
    }
  }}, 'Hello World');
  log.write(entry);
  console.log(`Wrote a log`);

  const message = JSON.stringify({
    message: random.toString(36).substring(2, 15),
  });
  
  console.log('Publishing message "'+message+'" to topic');

  return pubsub
    .topic('projects/toto-228009/topics/example')
    .publisher()
    .publish(Buffer.from(message))
    .then(() => res.status(200).send('Message published.'))
    .catch(err => {
      console.error(err);
      res.status(500).send(err);
      return Promise.reject(err);
    });
};

subscribe.js

'use strict';

exports.subscribe = (event, callback) => {
  console.log(JSON.parse(Buffer.from(event.data, 'base64').toString()));
};