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How to Build a Google Cloud Function Example for NodeJS with YAML secrets, CORS, and local testing

This is an example starter codebase for launching a cloud function into Google Cloud Platform (GCP). Learn more about cloud functions at https://cloud.google.com/functions/. This cloud function is written in NodeJS v8.

This README serves as a tutorial on how to launch your first cloud function with Node JS. Conducted on macOS Mojave. Run through can be done in 15 minutes.

No time for a for a tutorial? Jump right into the code base: https://github.com/zesty-io/google-cloud-function-node-example

Why Zesty.io made this Tutorial

Zesty.io is a cloud headless content management system. Integrations are extensions are often made leveraging cloud functions. At Zesty.io we use cloud functions for many of our side services, and really enjoy their quick deployment, reliability, and cheap cost structure.

Getting Started

Setting up your Environment

  1. Create a Google Cloud account and create a project (MY_PROJECT will be used as an example)

  2. Download and install Google Cloud SDK https://cloud.google.com/sdk/docs/quickstarts and from your terminal run gcloud auth login

  3. Install NodeJS https://nodejs.org/en/

  4. Install Node Version Manager (NVM) from your terminal run curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.34.0/install.sh | bash in your terminal

  5. Install GCP functions emulator for local testing by running npm install -g @google-cloud/functions-emulator in your terminal

  6. Setting functions emulator functions config set projectId MY_PROJECT, and run functions start

  7. Install a code editor like Atom.io or VS Code

  8. (OPTIONAL)Install Postman to make test requests the cloud function (rather than using your browser)

Setting up your project

You are going to use your terminal to run most commands.

  1. Create a new directory on your computer e.g. mkdir ./my-cloud-function

  2. run cd ./my-cloud-function to open the directory

  3. run npm init and fill out the init question prompted in terminal, defaults are fine

  4. run npm install cors installs a package we will use to control cross origin resource sharing

  5. run npm install env-yaml installs a package to read a local yaml file with secrets

  6. run nvm use v8 to use node8

  7. run echo "v8" > .nvmrc to create an nvm file to always use node 8 when you open the directory

  8. run touch .env.yaml to create your base secret file

  9. run echo ".env.yaml" > .gitignore to create a file that tells git not to commit secrets (security reasons)

  10. run touch index.js to create your base javascript file

Coding NodeJS in the Index.js file


  1. run code . or atom . to open the directory in your code editor

  2. open .env.yaml and add this line TEST_SECRET: hello world which creates a secret string TEST_SECRET

  3. open index.js and add this code:

require('env-yaml').config({ path: './.env.yaml' })

this code will load up your secret file and output a secret to console

  1. run node index.js to see hello world outputted to the terminal. At this point if you are running into errors, trace back to the Getting Starting section and walk through every step again.

  2. open index.js and replace all the code your wrote with:

require('env-yaml').config({ path: './.env.yaml' })

exports.myFunction = (req, res) => { const cors = require('cors')()

cors(req, res, () => { myFunction(req, res) }) }

const myFunction = async (req, res) => { res.send(process.env.TEST_SECRET) }

Now you are ready to test!

Deploying locally

  1. run functions deploy myFunction --env-vars-file .env.yaml --trigger-http which will create a local testable function, if this ran successfully, it will return you a url for your function, mine was http://localhost:8010/my-project/us-central1/myFunction, to test the function copy that url.

  2. open your function url in a web browser, you should see "hello world"

If these steps failed you, you need to check your environment setup be going over easy step in getting started.

Deploying to the Google Cloud Platform

  1. run gcloud functions deploy myFunction --trigger-http --project=my-project --env-vars-file .env.yaml --runtime=nodejs8 --memory=256mb --timeout=240s"

  2. it should take 2 minutes to deploy, once deployed the terminal will display a URL to load it from remote, open that in your browser.


By Randy Apuzzo

Randy has had a penchant for computer programming from an early age and started applying his skills to build business software in 2004. Randy's stack of skills range from programming, system architecture, business know-how, to typographic design; which lends to a truly customer-centric and business effective software design. He leads the Zesty.io team as CEO.

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