Google Cloud Functions Boilerplate

Purpose

This template allows to kickstart the development of Google Cloud Platform (GCP) functions keeping the best practices of software development.

Cloud functions types

Official detailed documentation can be found here and we strongly recommend you read it.

There are two types of cloud functions that are offered by GCP:

1. HTTP Functions are used when you need to serve a response immediately and are activated usually by an HTTP call
2. Background functions performs usually longer running operations and responds to events such as a file change or PubSub event

Parameters and challenges for setting up functions are fundamentally different as well.

HTTP functions are similar to setting up a middleware and you will deal with topics such as HTTP verbs, CORS and multipart requests. A lot of useful examples here. There are two obvious parameters - request(req) and response(res), so if you are familiar with Express, it should be self explanatory

Background functions are used when response and request are processed asynchronously. There is a plenty of triggers provided by GCP, for example PubSub(message queue) and GCP Storage(file changes watchers). The full list of triggers is available here. There are two parameters - data or event trigger specific and the context contains additionally the information about the request.

Local setup

Functions framework allows to run functions locally by serving them as a web service. To start services just run

npm run background-function

OR

npm run http-function

The port is defined in package.json as localPort.

Smoke tests

To test HTTP function you can just curl the localhost port like this:

curl localhost:8080

Testing of background functions is more involved. Functions framework expects to pass certain headers, which does not correspond to actual behavior in productive environment. This is a bug well documented in #96 and in #41.

curl -d "@mockPubsub.json" \
  -X POST \
  -H "Ce-Type: true" \
  -H "Ce-Specversion: true" \
  -H "Ce-Source: true" \
  -H "Ce-Id: true" \
  -H "Content-Type: application/json" \
  http://localhost:8080

Features

• Templates functions
• Linting
• Unit test setup
• Integration test setup
• VS code configuration
• Deployment from local machine
• Deployment with Cloud Build
• System tests setup
• Docker image
• Git hooks