Adding Docker Bake to ease multi-stage/multi-platform builds

Author: rgrizzell

.github/workflows/docker-build.yml

@@ -3,40 +3,70 @@ name: Docker Image
 
 on:
   push:
-    tags: [ '*.*.*' ]
+#    tags: [ '*.*.*' ]
 
 env:
   REGISTRY_IMAGE: ghcr.io/rgrizzell/circuitpython
 
 jobs:
+  prepare:
+    runs-on: ubuntu-latest
+    outputs:
+      matrix: ${{ steps.platforms.outputs.matrix }}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Create matrix
+        id: platforms
+        run: |
+          echo "matrix=$(docker buildx bake runtime --print | jq -cr '.target."runtime".platforms')" >>${GITHUB_OUTPUT}          
+
+      - name: Show matrix
+        run: |
+          echo ${{ steps.platforms.outputs.matrix }}          
+
+      - name: Docker meta
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ${{ env.REGISTRY_IMAGE }}
+
+      - name: Rename meta bake definition file
+        run: |
+          mv "${{ steps.meta.outputs.bake-file }}" "/tmp/bake-meta.json"
+          mv "${{ steps.meta.outputs.bake-file-annotations }}" "/tmp/bake-annotations.json"
+
+      - name: Upload meta bake definition
+        uses: actions/upload-artifact@v4
+        with:
+          name: bake-meta
+          path: /tmp/bake-*.json
+          if-no-files-found: error
+          retention-days: 1
+
   build:
     runs-on: ubuntu-latest
+    needs:
+      - prepare
     strategy:
       fail-fast: false
       matrix:
-        platform:
-          - linux/amd64
-          - linux/arm64
+        platform: ${{ fromJson(needs.prepare.outputs.matrix) }}
     steps:
       - name: Prepare
         run: |
           platform=${{ matrix.platform }}
-          echo "PLATFORM_PAIR=${platform//\//-}" >> $GITHUB_ENV
+          echo "PLATFORM_PAIR=${platform//\//-}" >> $GITHUB_ENV          
 
       - name: Checkout
         uses: actions/checkout@v4
 
-      - name: Docker meta
-        id: meta
-        uses: docker/metadata-action@v5
+      - name: Download meta bake definition
+        uses: actions/download-artifact@v4
         with:
-          images: ${{ env.REGISTRY_IMAGE }}
-
-      - name: Set up QEMU
-        uses: docker/setup-qemu-action@v3
-
-      - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3
+          name: bake-meta
+          path: /tmp
 
       - name: Login to GitHub Container Registry
         uses: docker/login-action@v3
@@ -45,20 +75,31 @@ jobs:
           username: ${{ github.repository_owner }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
-      - name: Build and push by digest
-        id: build
-        uses: docker/build-push-action@v5
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Build
+        id: bake
+        uses: docker/bake-action@v5
         with:
-          context: .
-          platforms: ${{ matrix.platform }}
-          labels: ${{ steps.meta.outputs.labels }}
-          outputs: type=image,name=${{ env.REGISTRY_IMAGE }},push-by-digest=true,name-canonical=true,push=true,annotation-index.org.opencontainers.image.description=CircuitPython for Linux,annotation-index.org.opencontainers.image.license=MIT
+          files: |
+            ./docker-bake.hcl
+            /tmp/bake-meta.json
+            /tmp/bake-annotations.json
+          targets: image
+          set: |
+            *.tags=
+            *.platform=${{ matrix.platform }}
+            *.output=type=image,"name=${{ env.REGISTRY_IMAGE }}",push-by-digest=true,name-canonical=true,push=true            
 
       - name: Export digest
         run: |
           mkdir -p /tmp/digests
-          digest="${{ steps.build.outputs.digest }}"
-          touch "/tmp/digests/${digest#sha256:}"
+          digest="${{ fromJSON(steps.bake.outputs.metadata).image['containerimage.digest'] }}"
+          touch "/tmp/digests/${digest#sha256:}"          
 
       - name: Upload digest
         uses: actions/upload-artifact@v4
@@ -73,35 +114,35 @@ jobs:
     needs:
       - build
     steps:
+      - name: Download meta bake definition
+        uses: actions/download-artifact@v4
+        with:
+          name: bake-meta
+          path: /tmp
+
       - name: Download digests
         uses: actions/download-artifact@v4
         with:
           path: /tmp/digests
           pattern: digests-*
           merge-multiple: true
 
-      - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3
-
-      - name: Docker meta
-        id: meta
-        uses: docker/metadata-action@v5
-        with:
-          images: ${{ env.REGISTRY_IMAGE }}
-
       - name: Login to GitHub Container Registry
         uses: docker/login-action@v3
         with:
           registry: ghcr.io
           username: ${{ github.repository_owner }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
       - name: Create manifest list and push
         working-directory: /tmp/digests
         run: |
-          docker buildx imagetools create $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
-            $(printf '${{ env.REGISTRY_IMAGE }}@sha256:%s ' *)
+          docker buildx imagetools create $(jq -cr '.target."docker-metadata-action".tags | map(select(startswith("${{ env.REGISTRY_IMAGE }}")) | "-t " + .) | join(" ")' /tmp/bake-meta.json) \
+            $(printf '${{ env.REGISTRY_IMAGE }}@sha256:%s ' *)          
 
       - name: Inspect image
         run: |
-          docker buildx imagetools inspect ${{ env.REGISTRY_IMAGE }}:${{ steps.meta.outputs.version }}
+          docker buildx imagetools inspect ${{ env.REGISTRY_IMAGE }}:$(jq -r '.target."docker-metadata-action".args.DOCKER_META_VERSION' /tmp/bake-meta.json)

docker-bake.hcl

@@ -0,0 +1,36 @@
+variable "DEFAULT_TAG" {
+  default = "rgrizzell/circuitpython:9.2.1"
+}
+
+// Special target: https://github.com/docker/metadata-action#bake-definition
+target "docker-metadata-action" {
+  tags = ["${DEFAULT_TAG}"]
+}
+
+// Default target if none specified
+group "default" {
+  targets = ["local"]
+}
+
+target "image" {
+  inherits = ["docker-metadata-action"]
+}
+
+target "local" {
+  inherits = ["image"]
+  output = ["type=docker"]
+}
+
+target "base" {
+  inherits = ["image"]
+  target = "base"
+  platforms = [
+    "linux/amd64",
+    "linux/arm64"
+  ]
+}
+
+target "runtime" {
+  inherits = ["base"]
+  target = "runtime"
+}