Setup Go Faster

It's like actions/setup-go but faster.

A Note About Go 1.21.0

Use [email protected] or later if you want to install Go 1.21.0.

With the release of go1.21.0, the Go team has changed the way they style dot-zero releases. They used to be styled like go1.N, but now they are go1.N.0. This caused issues with earlier versions of setup-go-faster.

Faster

Setup-go-faster takes about a third as long as setup-go to install go on a runner.

These are the median times¹ for installing go 1.20.7 and tip as of August 2023.

runner os	go-version	setup-go	setup-go-faster	improvement
ubuntu-20.04	1.20.7	8s	3s	5s
macos-11	1.20.7	34s	12s	22s
windows-2022	1.20.7	80s	12s	68s
ubuntu20.04	tip	unsupported	311s	∞
macos-11	tip	unsupported	313s	∞
windows-2022	tip	unsupported	576s	∞

The performance improvements are achieved by:

• The magic of Bash, curl and Perl. Maybe they aren't the most modern, but they are a heck of a lot faster than loading nodejs to do some simple version checks and downloads.

• Installing to the faster volume on Windows. On windows runners it takes significantly longer to write to C: vs D:. Setup-go installs go to C:, but setup-go-faster installs to D:

• Shortcuts for version checks. Setup-go-faster supports all the same pseudo-semver ranges as setup-go, but it is optimized for exact versions ( like 1.15.7) and 1.15.x style ranges. Our version check is faster to begin with, but if you use one of those formats you can shave an additional half second off the time.

Install tip

Setup-go-faster will install go tip from source if you set go-version: tip.

Check out the outputs

Look at those outputs. If you want to use GOPATH or GOMODCACHE as input in some other step, you can just grab it from setup-go-faster's output instead of having to add another step just to set an environment variable.

What's missing?

Just the stable input. I don't understand what stable adds for actions/setup-go. If you only want stable builds you can set go-version accordingly. If there is good use case for stable, it can be added.

Inputs

go-version

The version of go to install. It can be an exact version or a semver constraint like '1.14.x' or '^1.14.4'. Do not add "go" or "v" to the beginning of the version.

Action runners come with some versions of go pre-installed. If any of those versions meet your semver constraint setup-go-faster will use those instead of checking whether a newer go available for download that meets your constraint. You can change this with the ignore-local input below.

A special case value for go-version is tip which causes setup-go-faster to install the gotip from source. Be warned there is nothing fast about this. It takes between 3 and 5 minutes on Ubuntu runners and is even slower on Windows and MacOS runners.

Go versions aren't really semvers, but they are close enough to use semver constraints for the most part. There are a some gotchas to watch out for:

• Prior to go1.21, Go doesn't release .0 versions. The first 1.15.x release is 1.15, not 1.15.0. This means if you have set go-version to 1.15, when 1.15.1 is released it won't be used because 1.15 is an exact match. If you want any go in the 1.15 family, set go-version to 1.15.x. For consistency, setup-go-faster@v1 continues to handle constraints for post 1.21 the same as pre 1.21. This may change in a future major version.

• Go's pre-releases are not valid semver. For example the beta for 1.16 is 1.16beta1. This means pre-releases need to be explicitely specified.

For those who learn best from examples:

go-version	description
1.15.6	installs 1.15.6
1.15beta1	installs 1.15beta1
1.15.x	installs the newest go that starts with 1.15
1.15	installs go 1.15, nothing newer. You generally do not want this and should use 1.15.x instead.
*	installs the newest go without any other constraints
^1.15.4	installs a go that is >= 1.15.4 and < 2
~1.15.4	installs a go that is >= 1.15.4 and < 1.16
< 1.15.6 >= 1.15.4	installs a go that is >= 1.15.4 and < 1.15.6
tip	installs gotip from source

go-version-file

Path to the go.mod or go.work file.

ignore-local

Normally a pre-installed version of go that meets the go-version constraints will be used instead of checking whether a newer version is available for download. With ignore-local, the action will always check for a newer version available for download. Set this to any non-empty value to enable.

Outputs

GOCACHE

output of go env GOCACHE

GOMODCACHE

output of go env GOMODCACHE

GOPATH

output of go env GOPATH

GOROOT

output of go env GOROOT

GOTOOLDIR

output of go env GOTOOLDIR

Footnotes

1. These results come from speedrun and speedrun-tip from the WillAbides/test-setup-go-faster repo. ↩