cloudbuild-notifier.js

const { IncomingWebhook } = require('@slack/webhook');
const url = process.env.SLACK_WEBHOOK_URL;

const webhook = new IncomingWebhook(url);

// subscribeSlack is the main function called by Cloud Functions.
module.exports.subscribeSlack = (pubSubEvent, context) => {
  const build = eventToBuild(pubSubEvent.data);

  // Skip if the current status is not in the status list.
  // Add additional statuses to list if you'd like:
  // QUEUED, WORKING, SUCCESS, FAILURE,
  // INTERNAL_ERROR, TIMEOUT, CANCELLED
  const status = ['SUCCESS', 'FAILURE', 'INTERNAL_ERROR', 'TIMEOUT'];
  if (status.indexOf(build.status) === -1) {
    return;
  }

  // Send message to Slack.
  const message = createSlackMessage(build);
  webhook.send(message);
};

// eventToBuild transforms pubsub event message to a build object.
const eventToBuild = (data) => {
  return JSON.parse(Buffer.from(data, 'base64').toString());
}

// createSlackMessage creates a message from a build object.
const createSlackMessage = (build) => {
  const STATUS_COLOR = {
    SUCCESS: '#34A853', // green
    FAILURE: '#EA4335', // red
    TIMEOUT: '#FBBC05', // yellow
    INTERNAL_ERROR: '#EA4335', // red
  }
  const message = {
    text: 'Build logs',
    mrkdwn: true,
    attachments: [
      {
        color: STATUS_COLOR[build.status],
        title: 'Build logs',
        title_link: build.logUrl,
        fields: [{
          title: 'Status',
          value: build.status
        }]
      }
    ]
  }

  // Add image(s) to the message.
  const images = build.images || [];
  if (images.length) {
    message.attachments[0].fields.push({
      title: `Image${(images.length > 1) ? 's' : ''}`,
      value: images.join('\n'),
    });
  }
  return message;
}