Google Cloud Functions to resize compute instance-group

index.js

const {Buffer} = require('safe-buffer');
const Compute = require('@google-cloud/compute');
const compute = new Compute();

/**
 * Resize Compute Engine instance-group.
 *
 * Expects a PubSub message with JSON-formatted event data containing the
 * following attributes:
 *  zone - the GCP zone the instances are located in.
 *  name - the name of a instance group.
 *  size - the number of instance(s) to resize
 *
 *
 * @param {!object} event Cloud Function PubSub message event.
 * @param {!object} callback Cloud Function PubSub callback indicating completion.
 */
exports.resizeInstanceGroupPubSub = (event, context, callback) => {
  try {
    const payload = _validatePayload(
      JSON.parse(Buffer.from(event.data, 'base64').toString())
    );

    const zone = compute.zone(payload.zone);
	const instanceGroupManager = zone.instanceGroupManager(payload.name);
    instanceGroupManager.resize(payload.size).then(data => {
      // Operation pending.
      const operation = data[0];
      const apiResponse = data[1];
      console.log(apiResponse);
      return operation.promise();
    }).then(() => {
      // Operation complete. Instance successfully stopped.
      const message = 'Successfully resize to ' + payload.size + ' the instance group named ' + payload.name;
      console.log(message);
      callback(null, message);
    }).catch(err => {
      console.log(err);
      callback(err);
    });
  } catch (err) {
    console.log(err);
    callback(err);
  }
};


/**
 * Validates that a request payload contains the expected fields.
 *
 * @param {!object} payload the request payload to validate.
 * @return {!object} the payload object.
 */
function _validatePayload(payload) {
  if (!payload.zone) {
    throw new Error(`Attribute 'zone' missing from payload`);
  } else if (!payload.name) {
    throw new Error(`Attribute 'name' missing from payload`);
  } else if (!payload.size) {
    throw new Error(`Attribute 'size' missing from payload`);
  }
  return payload;
}

package.json

{
  "name": "cloud-functions-schedule-resize-instance-group",
  "version": "0.1.0",
  "private": true,
  "license": "Apache-2.0",
  "author": "Google Inc.",
  "repository": {
    "type": "git",
    "url": "https://github.com/GoogleCloudPlatform/nodejs-docs-samples.git"
  },
  "engines": {
    "node": ">=8.0.0"
  },
  "scripts": {
    "test": "mocha test/*.test.js --timeout=20000"
  },
  "devDependencies": {
    "@google-cloud/nodejs-repo-tools": "^3.3.0",
    "mocha": "^6.0.0",
    "proxyquire": "^2.0.0",
    "sinon": "^7.0.0"
  },
  "dependencies": {
    "@google-cloud/compute": "^1.0.0",
    "safe-buffer": "^5.1.2"
  }
}

test_function_payload.md

For Triggering event enter the following:

{"data":"eyJ6b25lIjogImFzaWEtc291dGhlYXN0MS1jIiwgIm5hbWUiOiAieW91ci1pbnN0YW5jZS1ncm91cC1uYW1lIiwgInNpemUiOiAiMSJ9="}

This is simply the base64-encoded string for:

{"zone": "asia-southeast1-c", "name": "your-instance-group-name", "size": "1"}

I'm so sorry. How to use this example to change the Instance group

I want to change the Instance group - Number of instances

@Daniel-svg for regional you need to use the RegionInstanceGroupManagers I create one js based in @vukhanhtruong js, take a look if help https://github.com/vrealtiago/gcp-compute/blob/main/resize-region-instance-group.js

@vrealtiago Sorry for the late reply. Thank you for making time for me. I really appreciate it. I will test again in my project.