build.yaml

name: Create and publish Docker images
on:
  push:
    branches: ["main"]
    paths:
      - "images/**"
      - ".github/workflows/build.yaml"
  workflow_dispatch: 
    inputs:
      imageName:
        description: 'Name of the image to build (leave empty to build all changed images)'
        required: false
        default: ''
env:
  REGISTRY: ghcr.io

jobs:
  find-changes:
    runs-on: ubuntu-latest
    outputs:
      matrix: ${{ steps.set-matrix.outputs.matrix }}
    steps:
      - name: Checkout repository
        uses: actions/checkout@v3

      - name: Get changed files
        id: getfile
        uses: lots0logs/gh-action-get-changed-files@2.2.2
        with:
          token: ${{ secrets.GITHUB_TOKEN }}

      - name: Determine changed images or rebuild all
        id: set-matrix
        run: |
          if [ "${{ github.event_name }}" == "workflow_dispatch" ]; then
            # Special Case for workflow_dispatch
            if [ -n "${{ github.event.inputs.imageName }}" ]; then
              images=($(ls -d images/* | sed 's|images/||'))
              matrix_value=$(echo "[\"${images[@]}\"]" | sed 's/ /","/g')
            else
              matrix_value="[\"${{ github.event.inputs.imageName }}\"]"
            fi
          else
            all_files=$(echo '${{ steps.getfile.outputs.all }}' | jq -r '.[]')
            if echo "$all_files" | grep -q ".github/workflows/build.yaml"; then
              images=($(ls -d images/* | sed 's|images/||'))
              matrix_value=$(echo "[\"${images[@]}\"]" | sed 's/ /","/g')
            else
              images=()
              for file in $all_files
              do
                if [[ $file == images/* ]]; then
                  image_name=$(echo $file | cut -d'/' -f2)
                  images+=("$image_name")
                fi
              done
              # Removing duplicate entries
              images=($(echo "${images[@]}" | tr ' ' '\n' | sort -u | tr '\n' ' '))
              matrix_value="[\"${images[*]}\"]"
            fi
          fi
          echo "matrix=${matrix_value}" >> $GITHUB_OUTPUT

  build-and-push-image:
    needs: find-changes
    runs-on: ubuntu-latest
    strategy:
      fail-fast: false
      matrix:
        image: ${{fromJson(needs.find-changes.outputs.matrix)}}
    permissions:
      contents: read
      packages: write
    env:
      IMAGE_NAME: ${{ github.repository_owner }}/example-${{ matrix.image }}
    steps:
      - name: Checkout repository
        uses: actions/checkout@v3
      - name: Set up QEMU
        uses: docker/setup-qemu-action@v3
      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3
      - name: Log in to the Container registry
        uses: docker/login-action@v2
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}
      - name: Extract metadata (tags, labels) for Docker
        id: meta
        uses: docker/metadata-action@v4
        with:
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
      - name: Build and push Docker image
        uses: docker/build-push-action@4c1b68d83ad20cc1a09620ca477d5bbbb5fa14d0
        with:
          context: ./images/${{ matrix.image }}
          push: true
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}
          cache-from: type=gha
          cache-to: type=gha,mode=max
          platforms: linux/amd64,linux/arm64