Set up Go

Repo: actions/setup-go

Set up your GitHub Actions workflow with a specific version of Go

Samples

Download a single Go version

The Go version will be the latest unless you specify a version.

Previously downloaded versions will be used from cache, to save on downloading. Which means if omit the version, I think you’d end up loading from cache 1.15 even when 1.18 is latest.

steps:
  - name: Set up Go
    uses: actions/setup-go@v2
    with:
      go-version: 1.15

Or a version range like '^1.13.1'.

Sample output:

Run actions/setup-go@v2

Set up go stable version spec 1.15
Found in cache @ /opt/hostedtoolcache/go/1.15.6/x64
Added go to the path
Successfully set up go version 1.15
go version go1.15.6 linux/amd64

go env
  GO111MODULE=""
  GOARCH="amd64"
  GOBIN=""
  ...

Download and run Go in your project

Here is the Action with more steps around it.

• main.yml

    steps:
      - name: Checkout
      - uses: actions/checkout@v2
  
      - name: Set up Go
        uses: actions/setup-go@v2
        with:
          go-version: '^1.13.1'
  
      - name: Show Go version
        run: go version
  
      - name: Greet
        run: go run hello.go
  

Load Go version dynamically

Use grep to find the version in go.mod file or Dockerfile.

Use GitHub env file and go.mod

This stores GO_VERSION=1.15 in a file that named using $GITHUB_ENV. That file is then read in the next step. See more info on $GITHUB_ENV on this Persist guide in my cheatsheets.

• main.yml

    steps:
      - name: Checkout
        uses: actions/checkout@v2
  
      - name: Get Go version
        run: echo "GO_VERSION=$(grep 'go \d\.' go.mod | cut -d ' ' -f 2)" >> $GITHUB_ENV
  
      - name: Set up Go
        uses: actions/setup-go@v2
        with:
          go-version: ${{ env.GO_VERSION }}
  

Thanks to comment here on a setup-go issue.

That the regex groups or -o flag are not used here, but cut command is. Which means the regex pattern can be short as go \d\. (assuming single digit major version) or longer as go \d+\.\d+' but with egrep.

Use outputs and Dockerfile

Based on iron-go-project.

• Dockerfile

    FROM golang:1.15
  

• main.yml

    steps:
      - name: Checkout
        uses: actions/checkout@v2
  
      - name: Get Go version
        id: vars
        run: |
          echo ::set-output name=go_version::$(grep '^FROM go' .github/go/Dockerfile | cut -d ' ' -f 2 | cut -d ':' -f 2)
          echo "Using Go version ${{ steps.vars.outputs.go_version }}"
  
      - name: Set up Go
        uses: actions/setup-go@v2
        with:
          go-version: ${{ steps.vars.outputs.go_version }}
  

Matrix version

How to run against multiple Go version. Based on the action’s doc.

• main.yml

    jobs:
      build:
        runs-on: ubuntu-latest
  
        strategy:
          matrix:
            go: [ '1.14', '1.13' ]
  
        name: Go ${{ matrix.go }}
  
        steps:
          - uses: actions/checkout@v2
          - name: Set up go
            uses: actions/setup-go@v1
            with:
              go-version: ${{ matrix.go }}
  
          - run: go run hello.go