lint_docker_image.yml

name: Lint Docker Images

on:
  pull_request:
    paths:
      - '*Dockerfile'

jobs:
  changed-images:
    runs-on: ubuntu-latest
    name: List changed images
    steps:
      - name: Check out source repository
        uses: actions/checkout@v3
        with:
          fetch-depth: 0
      - name: Get changed files
        id: changed-files
        uses: tj-actions/changed-files@v38
        with:
          files: '*Dockerfile'
          json: true
      - name: Create Job Matrix
        id: image-matrix
        run: echo images=${{ steps.changed-files.outputs.all_changed_files }} >> $GITHUB_OUTPUT
    outputs:
      images: ${{ steps.image-matrix.outputs.images }}

  hadolint:
    name: Lint Docker Images
    runs-on: ubuntu-latest
    permissions:
      pull-requests: write
    # Skip job if there are no images to test
    # https://github.com/dorny/paths-filter/issues/66
    if: ${{ needs.changed-images.outputs.images != '' && toJson(fromJson(needs.changed-images.outputs.images)) != '[]' }}
    needs: [changed-images]
    strategy:
      matrix:
        image: ${{ fromJSON(needs.changed-images.outputs.images) }}
      fail-fast: false
    steps:
      - name: Checkout
        uses: actions/checkout@v3
      - uses: hadolint/hadolint-action@v3.1.0
        id: hadolint
        with:
          dockerfile: ${{ matrix.image }}
          ignore: DL3002,DL3008,DL3013,DL3016
      - name: Annotate Pull Request
        uses: actions/github-script@v6
        if: github.event_name == 'pull_request' && failure()
        with:
          script: |
            const output = `
            #### Hadolint: \`${{ steps.hadolint.outcome }}\`
            \`\`\`
            ${process.env.HADOLINT_RESULTS}
            \`\`\`
            `;

            github.rest.issues.createComment({
              issue_number: context.issue.number,
              owner: context.repo.owner,
              repo: context.repo.repo,
              body: output
            })