test_dockerfiles.yaml

name: Dockerfile tests
on:
  push:
    branches:
      - main
  pull_request:
    paths:
      - '**/Dockerfile'
  schedule:
    - cron: '23 2 * * 0'
concurrency:
  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
  cancel-in-progress: true
jobs:
  define_changed_dockerfile_matrix:
    runs-on: ubuntu-latest
    outputs:
      matrix: ${{ steps.changed-dockerfiles.outputs.all_changed_files }}
    steps:
      - uses: actions/checkout@v4
      -
        name: Get Changed Dockerfiles
        id: changed-dockerfiles
        uses: tj-actions/changed-files@v44
        with:
          matrix: true
          files: '**Dockerfile'
  
  define_all_dockerfile_matrix:
    runs-on: ubuntu-latest
    outputs:
      matrix: ${{ steps.all-dockerfiles.outputs.files}}
    steps:
      - uses: actions/checkout@v4
      -
        name: Get all Dockerfiles
        id: all-dockerfiles
        run: |
             find . -name "Dockerfile" | jq -Rs '{"files": split("\n") | map(select(. != ""))}' >> "$GITHUB_OUTPUT"

  test_builds:
    runs-on: ubuntu-latest
    needs: [define_changed_dockerfile_matrix, define_all_dockerfile_matrix]
    strategy:
      matrix:
        dockerfile: ${{ github.ref != 'refs/heads/main' && fromJSON(needs.define_changed_dockerfile_matrix.outputs.matrix) || fromJSON(needs.define_all_dockerfile_matrix.outputs.matrix) }}

    steps:
      - uses: actions/checkout@v4
      -
        name: Get context
        id: get-context
        run: |
            echo "context=$(dirname ${{ matrix.dockerfile }})" >> $GITHUB_OUTPUT

      -
        name: Build
        uses: docker/build-push-action@v6
        with:
          context: ${{ get-context.outputs.context }}
          file: ${{ matrix.dockerfile }}