The Setup
You may find yourself working in a Go mono repo and someone has asked you to deploy a Function to Google Cloud Platform (GCP).
You may have a few questions:
- How do I deploy a Go function to GCP?
- How do I deploy multiple functions from a single repo?
- Why is this so hard?
I’ll start with the last question first.
Why is this so hard?
There is a heuristic I like to use when I am building or designing software. If something is hard, I’m probably adding unnecessary complexity and I should rethink my approach.
That applies to this scenario. The Go tooling isn’t designed to support this use case well. There are easier ways to build and deploy multiple Go applications from a monorepo. But, you may find yourself in the situation where you do not have a choice (most likely due to a long-list of prior choices that can’t be undone).
How do I deploy a Go function to GCP?
Deploying a single function from a repository that only contains that function is pretty straightforward.
You can follow the official documentation to deploy a single function; but
all you need is a .go file with your handler and a go.mod file. Easy.
Things get a little more complicated when you have multiple functions in a single repository.
How do I deploy multiple functions in a single repo?
// TODO: add dummy repository with multiple functions and outline steps here
- Parent go.mod
- workspace file
- directory for each function
- go.mod for each function
- vendor directory for each function
- deploy script for easy deployments
#!/bin/bash
for d in */; do
gcloud functions deploy $(basename $d) \
--runtime go113 \
--trigger-http \
--entry-point=Handler \
--source=$d
done
The easier way
I prefer to use Cloud Run and deploy containers instead of functions. This allows me to build and deploy multiple Go applications from a single repository with ease.