golangci-lint-action

It's the official GitHub action for golangci-lint from its authors. The action runs golangci-lint and reports issues from linters.

Compatibility

• v3.0.0+ requires explicit setup-go installation step prior to using this action: uses: actions/setup-go@v3. The skip-go-installation option has been removed.
• v2.0.0+ works with golangci-lint version >= v1.28.3
• v1.2.2 is deprecated due to we forgot to change the minimum version of golangci-lint to v1.28.3 (issue)
• v1.2.1 works with golangci-lint version >= v1.14.0 (issue)

How to use

Add .github/workflows/golangci-lint.yml with the following contents:

name: golangci-lint
on:
  push:
    branches:
      - master
      - main
  pull_request:

permissions:
  contents: read
  # Optional: allow read access to pull request. Use with `only-new-issues` option.
  # pull-requests: read

jobs:
  golangci:
    name: lint
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - uses: actions/setup-go@v4
        with:
          go-version: '1.21'
          cache: false
      - name: golangci-lint
        uses: golangci/golangci-lint-action@v3
        with:
          # Require: The version of golangci-lint to use.
          # When `install-mode` is `binary` (default) the value can be v1.2 or v1.2.3 or `latest` to use the latest version.
          # When `install-mode` is `goinstall` the value can be v1.2.3, `latest`, or the hash of a commit.
          version: v1.54

          # Optional: working directory, useful for monorepos
          # working-directory: somedir

          # Optional: golangci-lint command line arguments.
          #
          # Note: By default, the `.golangci.yml` file should be at the root of the repository.
          # The location of the configuration file can be changed by using `--config=`
          # args: --timeout=30m --config=/my/path/.golangci.yml --issues-exit-code=0 

          # Optional: show only new issues if it's a pull request. The default value is `false`.
          # only-new-issues: true

          # Optional: if set to true, then all caching functionality will be completely disabled,
          #           takes precedence over all other caching options.
          # skip-cache: true

          # Optional: if set to true, then the action won't cache or restore ~/go/pkg.
          # skip-pkg-cache: true

          # Optional: if set to true, then the action won't cache or restore ~/.cache/go-build.
          # skip-build-cache: true

          # Optional: The mode to install golangci-lint. It can be 'binary' or 'goinstall'.
          # install-mode: "goinstall"

We recommend running this action in a job separate from other jobs (go test, etc) because different jobs run in parallel.

Multiple OS Support

If you need to run linters for specific operating systems, you will need to use the action >=v2. Here is a sample configuration file:

name: golangci-lint
on:
  push:
    branches:
      - master
      - main
  pull_request:

permissions:
  contents: read
  # Optional: allow read access to pull request. Use with `only-new-issues` option.
  # pull-requests: read

jobs:
  golangci:
    strategy:
      matrix:
        go: ['1.21']
        os: [macos-latest, windows-latest]
    name: lint
    runs-on: ${{ matrix.os }}
    steps:
      - uses: actions/checkout@v3
      - uses: actions/setup-go@v4
        with:
          go-version: ${{ matrix.go }}
          cache: false
      - name: golangci-lint
        uses: golangci/golangci-lint-action@v3
        with:
          # Require: The version of golangci-lint to use.
          # When `install-mode` is `binary` (default) the value can be v1.2 or v1.2.3 or `latest` to use the latest version.
          # When `install-mode` is `goinstall` the value can be v1.2.3, `latest`, or the hash of a commit.
          version: v1.54

          # Optional: working directory, useful for monorepos
          # working-directory: somedir

          # Optional: golangci-lint command line arguments.
          # 
          # Note: by default the `.golangci.yml` file should be at the root of the repository.
          # The location of the configuration file can be changed by using `--config=`
          # args: --timeout=30m --config=/my/path/.golangci.yml --issues-exit-code=0

          # Optional: show only new issues if it's a pull request. The default value is `false`.
          # only-new-issues: true

          # Optional:The mode to install golangci-lint. It can be 'binary' or 'goinstall'.
          # install-mode: "goinstall"

You will also likely need to add the following .gitattributes file to ensure that line endings for Windows builds are properly formatted:

*.go text eol=lf

Comments and Annotations

Currently, GitHub parses the action's output and creates annotations.

The restrictions of annotations are the following:

1. Currently, they don't support markdown formatting (see the feature request)
2. They aren't shown in the list of comments like it was with golangci.com. If you would like to have comments - please, up-vote the issue.

To enable annotations, you need to add the `checks' permission to your action.

permissions:
  # Required: allow read access to the content for analysis.
  contents: read
  # Optional: allow read access to pull request. Use with `only-new-issues` option.
  pull-requests: read
  # Optional: Allow write access to checks to allow the action to annotate code in the PR.
  checks: write

Performance

The action was implemented with performance in mind:

1. We cache data by @actions/cache between builds: Go build cache, Go modules cache, golangci-lint analysis cache.
2. We don't use Docker because image pulling is slow.
3. We do as much as we can in parallel, e.g. we download cache, go, and golangci-lint binary in parallel.

For example, in a repository of golangci-lint running this action without the cache takes 50s, but with cache takes 14s:

• in parallel:
  • 4s to restore 50 MB of cache
  • 1s to find and install golangci-lint
• 1s to run golangci-lint (it takes 35s without cache)

Internals

We use JavaScript-based action. We don't use Docker-based action because:

1. docker pulling is slow currently
2. it's easier to use caching from @actions/cache

We support different platforms, such as ubuntu, macos, and windows with x32 and x64 archs.

Inside our action, we perform 3 steps:

1. Setup environment running in parallel:

• restore cache of previous analyses
• fetch action config and find the latest golangci-lint patch version for needed version (users of this action can specify only minor version of golangci-lint). After that install golangci-lint using @actions/tool-cache

2. Run golangci-lint with specified by user args
3. Save cache for later builds

Caching internals

1. We save and restore the following directories: ~/.cache/golangci-lint, ~/.cache/go-build, ~/go/pkg.
2. The primary caching key looks like golangci-lint.cache-{interval_number}-{go.mod_hash}. Interval number ensures that we periodically invalidate our cache (every 7 days). go.mod hash ensures that we invalidate the cache early - as soon as dependencies have changed.
3. We use restore keys: golangci-lint.cache-{interval_number}-. GitHub matches keys by prefix if we have no exact match for the primary cache.

This scheme is basic and needs improvements. Pull requests and ideas are welcome.

Development of this action

1. Install act
2. Make a symlink for act to work properly: ln -s . golangci-lint-action
3. Prepare deps once: npm run prepare-deps
4. Run npm run local after any change to test it