Enhance Docker publish workflow for multi-architecture

.github/workflows/docker-publish.yml

@@ -1,69 +1,82 @@
-name: Publish Docker image
-
-# To use this workflow:
-# * Change the IMAGE_NAME to yours - use lowercase only
-# * Enable automated build if you wish
+name: Publish Multi-Architecture Docker image
 
 env:
+  # The name of your image. This will be combined with your username/org.
   IMAGE_NAME: pihole
+  # Target registry
+  REGISTRY: ghcr.io
 
 on:
   workflow_dispatch:
-  ## Enable automated build by uncommenting the following lines:
   push:
-    # Publish `master` as Docker `latest` image.
+    # Trigger on pushes to the main branch (tags it as 'latest')
     branches:
       - main
-    # Publish `v1.2.3` tags as release `1.2.3`.
+    # Trigger on version tags like v1.0.1
     tags:
       - v*
 
 jobs:
-  # Test docker build before publishing
-  # test:
-  #   runs-on: ubuntu-latest
-
-  #   steps:
-  #     - uses: actions/checkout@v2
-
-  #     - name: Run tests
-  #       run: |
-  #         if [ -f docker-compose.test.yml ]; then
-  #           docker-compose --file docker-compose.test.yml build
-  #           # docker-compose --file docker-compose.test.yml run sut
-  #         else
-  #           docker build . --file Dockerfile
-  #         fi
-
-  # Push image to GitHub Packages.
   push:
-    # Ensure test job passes before pushing image.
-    # needs: test
-
     runs-on: ubuntu-latest
-    permissions: write-all
+    permissions:
+      contents: read
+      packages: write
+
     steps:
-      - uses: actions/checkout@v2
+      # 1. Checkout the source code from the repository
+      - name: Checkout repository
+        uses: actions/checkout@v4
 
-      - name: Build image
-        run: docker build . --file Dockerfile --tag $IMAGE_NAME
+      # 2. Set up QEMU (Quick Emulator)
+      # This allows building for different architectures (like ARM64) on an AMD64 runner
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+        with:
+          platforms: all
 
+      # 3. Set up Docker Buildx
+      # Buildx is the modern Docker CLI plugin that enables multi-platform builds
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      # 4. Login to GitHub Container Registry (GHCR)
+      # Uses the automatic GITHUB_TOKEN for authentication
       - name: Log into GitHub Container Registry
-        run: echo "${{ secrets.GITHUB_TOKEN }}" | docker login https://ghcr.io -u ${{ github.actor }} --password-stdin
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      # 5. Extract metadata (Tags & Labels)
+      # Automatically handles:
+      # - Lowercasing the image name
+      # - Creating 'latest' for the main branch
+      # - Creating semver tags (1.2.3) from git tags (v1.2.3)
+      - name: Extract Docker metadata
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ${{ env.REGISTRY }}/${{ github.repository_owner }}/${{ env.IMAGE_NAME }}
+          tags: |
+            type=ref,event=branch
+            type=semver,pattern={{version}}
+            type=raw,value=latest,enable=${{ github.ref == 'refs/heads/main' }}
 
-      - name: Push image to GitHub Container Registry
-        
-        run: |
-          IMAGE_ID=ghcr.io/${{ github.repository_owner }}/$IMAGE_NAME
-          # Change all uppercase to lowercase
-          IMAGE_ID=$(echo $IMAGE_ID | tr '[A-Z]' '[a-z]')
-          # Strip git ref prefix from version
-          VERSION=$(echo "${{ github.ref }}" | sed -e 's,.*/\(.*\),\1,')
-          # Strip "v" prefix from tag name
-          [[ "${{ github.ref }}" == "refs/tags/"* ]] && VERSION=$(echo $VERSION | sed -e 's/^v//')
-          # Use Docker `latest` tag convention
-          [ "$VERSION" == "main" ] && VERSION=latest
-          echo IMAGE_ID=$IMAGE_ID
-          echo VERSION=$VERSION
-          docker tag $IMAGE_NAME $IMAGE_ID:$VERSION
-          docker push $IMAGE_ID:$VERSION
+      # 6. Build and Push the Multi-Arch Image
+      # This builds the image for all specified platforms and pushes it to GHCR
+      - name: Build and push
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          # Pushes the image only on push events (not on PRs by default)
+          push: true
+          # List the architectures you want to support here:
+          platforms: linux/amd64,linux/arm64,linux/arm/v7
+          # Uses the tags and labels generated in step 5
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          # Enable caching to speed up subsequent builds
+          cache-from: type=gha
+          cache-to: type=gha,mode=max