Google Cloud Functions Go

This project contains a collection of tutorials and hacks for using Go with Google Cloud Functions.

Disclaimer

This is not an official Google product (experimental or otherwise), it is just code that happens to be owned by Google.

How it Works

Google Cloud Functions only supports node.js so shims must be used to wrap calls to Go code. The cloud-functions-go-shim binary bridges node.js and Go functions. Each Go function to be executed must be exported from a Go plugin.

The use of Go plugins limit the runtime environment to Linux.

Install

Download the cloud-functions-go and cloud-functions-go-shim binaries and put them in your path.

Usage

Build

Create a Go plugin holding the function to be executed:

go build -buildmode=plugin -o functions.so examples/topic/main.go

Test

Use the cloud-functions-go-shim to test your function:

cat examples/topic/event.json | \
  cloud-functions-go-shim -entry-point F -event-type topic -plugin-path functions.so 

Testing only works on Linux; a current limitation of Go plugins.

Package

The cloud-functions-go command is used to package your function along with the necessary shims for execution in the Cloud Functions environment.

cloud-functions-go -entry-point F -event-type topic -plugin-path functions.so

Output

wrote F-topic-1491796383.zip

The zip archive containes the following files:

• index.js - node.js shim that calls out to the cloud-functions-go-shim binary
• functions.so - the Go function to be executed
• cloud-functions-go-shim - the shim between node.js and Go

Deploy

Upload the zip archive and set the function to F and the trigger to topic.