GCF Go Template

Purpose

A template project to quickly start writing and deploying Google Cloud Functions using Go (Golang).

Usage

Build functions (create zip files). make build-functions

Deploy functions from pre-built zip files. make deploy-functions

Both of them. make update-functions

Clean everything. make clean

Note: Only macOS and Linux are supported.

The problem

According to the docs, you can either provide go.mod, or provide the vendor directory. But what if you want to use both a 3rd party module, and also a local shared module to be used by all of your functions (and the rest of the project?)

Solutions

• Easily use both a local shared module that is on your GOPATH (no relative imports) and 3rd party modules.
• Vendor once. Use everywhere.
• No unecessary copying of shared code / directories between functions.
• Easily upload multiple functions.

How is this working?

Taking advantage of the feature that symlinks are followed when zipping.

• Linking the the right spot in vendor directory to local shared module.
  • I guess that this is a bad practice, but it is overrided if we go mod vendor again so there are no implications.
• Linking each function directory to the vendor directory.
• Zipping each function.
• Uploading to GCS bucket.
• Creating functions from GCS.

Tree

This is basically the directory structure after building.

.
├── Makefile
├── README.md
├── functions
│   ├── HelloWorld
│   │   ├── fn.go
│   │   └── vendor -> /path/to/my/project/vendor
│   └── HelloWorld2
│       ├── fn.go
│       └── vendor -> /path/to/my/project/vendor
├── go.mod
├── go.sum
├── lib
│   └── consts.go
├── tmp
│   ├── HelloWorld.zip
│   └── HelloWorld2.zip
└── vendor
    ├── path
    │   └── to
    │       └── my
    │           └── project
    │               └── lib -> /path/to/my/project/lib
    ├── github.com
    │   ...
    └── modules.txt

TODO

• Automatically figure out local shared libs.