GitHub Actions includes CI/CD for free for Open Source repositories. This document contains information on making it work well for Go. See them in action:

$ cat .github/workflows/test.yml
on: [push, pull_request]
name: Test
jobs:
  test:
    strategy:
      matrix:
        go-version: [1.20.x, 1.21.x]
        os: [ubuntu-latest, macos-latest, windows-latest]
    runs-on: ${{ matrix.os }}
    steps:
    - uses: actions/checkout@v3
    - uses: actions/setup-go@v4
      with:
        go-version: ${{ matrix.go-version }}
    - run: go test ./...

Each workflow file has a number of jobs, which get run on specified events, and run concurrently with each other. You can have workflow status badges.

Each job runs on a configuration matrix. For example, we can test two major Go versions on three operating systems.

Each job has a number of steps, such as installing Go, or checking out the repository's code.

Note that name fields are optional.

They can be set up via env for an entire workflow, a job, or for each step:

env:
  GOPROXY: "https://proxy.company.com"
jobs:
  [...]

You can use environment files to set environment variables or add an element to $PATH. For example:

steps:
- name: Set env vars
  run: |
      echo "CGO_ENABLED=0" >> $GITHUB_ENV
      echo "${HOME}/goroot/bin" >> $GITHUB_PATH

Note that these take effect for future steps in the job.

Since v4, actions/setup-go caches GOCACHE and GOMODCACHE automatically, using go.sum as the cache key. You can turn that off via cache: false, and then you may also use your own custom caching, for example to only keep GOMODCACHE:

- uses: actions/cache@v3
  with:
    path: ~/go/pkg/mod
    key: ${{ runner.os }}-go-${{ hashFiles('**/go.sum') }}
    restore-keys: |
      ${{ runner.os }}-go-

See this guide for more details.

You can use if conditionals, using their custom expression language:

- if: github.event_name == 'push' && matrix.os == 'ubuntu-latest'
  run: go run ./endtoend

You can include extra matrix jobs, and you can exclude specific matrix jobs.

- name: Series of commands
  run: |
    go test ./...
    go test -race ./...

The biggest difference is the UI; workflow results are shown separately. Grouping jobs in workflows can also be useful if one wants to customize the workflow triggers, or to set up dependencies via needs.

Follow these steps to set up the secret in the repo's settings. After adding a secret like FOO_SECRET, use it on a step as follows:

- run: some-command
  env:
    FOO_SECRET: ${{ secrets.FOO_SECRET }}

It's possible to install modules from private GitHub repositories without using your own proxy. You'll need to add a personal access token as a secret environment variable, as well as configure GOPRIVATE. You can also directly used the token provided by GitHub in the workflow. You can define anything as username in the URL, it is not taken into account by GitHub.

- name: Configure git for private modules
  env:
    TOKEN: ${{ secrets.PERSONAL_ACCESS_TOKEN }}
  run: git config --global url."https://user:${TOKEN}@github.com".insteadOf "https://github.com"

env:
  GOPRIVATE: "*.company.com"
jobs:
  [...]

Use sudo apt, making sure to only run the step on Linux:

- if: matrix.os == 'ubuntu-latest'
  run: sudo apt update && sudo apt install -y --no-install-recommends mypackage

Declare GOPATH and clone inside of it:

jobs:
  test-gopath:
    env:
      GOPATH: ${{ github.workspace }}
      GO111MODULE: off
    defaults:
      run:
        working-directory: ${{ env.GOPATH }}/src/github.com/${{ github.repository }}
    steps:
    - uses: actions/checkout@v3
      with:
        path: ${{ env.GOPATH }}/src/github.com/${{ github.repository }}

• Concepts, rate limits, etc: https://docs.github.com/en/actions/learn-github-actions

• Syntax and fields reference: https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions

• Environment reference: https://docs.github.com/en/actions/using-github-hosted-runners/about-github-hosted-runners

• To report bugs: https://github.com/orgs/community/discussions/categories/actions-and-packages

• actions/checkout#135

git config core.autocrlf defaults to true, so be careful about CRLF endings in your plaintext testdata files on Windows. To work around this, set up the following .gitattributes:

* -text

• actions/runner-images#712

os.TempDir on Windows will contain a short name, since %TEMP% also contains it. Note that case sensitivity doesn't matter, and that os.Open should still work; but some programs not treating short names might break.

> echo %USERPROFILE%
C:\Users\runneradmin
> echo %TEMP%
C:\Users\RUNNER~1\AppData\Local\Temp