Try new strategy

Author: jorgensd

.github/workflows/publish_docker.yml

@@ -1,3 +1,4 @@
+# Recipe based on: https://docs.docker.com/build/ci/github-actions/multi-platform/#distribute-build-across-multiple-runners
 name: Publish tutorial docker image
 on:
   push:
@@ -29,8 +30,8 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v4
 
-      - name: Set up QEMU
-        uses: docker/setup-qemu-action@v3
+      # - name: Set up QEMU
+      #   uses: docker/setup-qemu-action@v3
 
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
@@ -41,6 +42,11 @@ jobs:
           registry: ${{ env.REGISTRY }}
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
 
       - name: Set architecture tag (amd64)
         if: ${{ matrix.os == 'ubuntu-24.04' }}
@@ -56,37 +62,97 @@ jobs:
         with:
           images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
 
-      - name: Build Docker image
+
+      - name: Build and push by digest
+        id: build
         uses: docker/build-push-action@v6
         with:
-          context: .
-          load: true
-          push: false
-          file: docker/Dockerfile
-          platforms: linux/${{ env.ARCH_TAG }}
-          tags: ${{ steps.meta.outputs.tags }}
+          platforms: ${{ matrix.os }}
           labels: ${{ steps.meta.outputs.labels }}
-          outputs: type=docker, dest=${{ runner.temp }}/image.tar
+          outputs: type=image,"name=${{ env.REGISTRY }}/${{ env.IMAGE_NAME}}",push-by-digest=true,name-canonical=true,push=true
+
+      - name: Export digest
+        run: |
+          mkdir -p ${{ runner.temp }}/digests
+          digest="${{ steps.build.outputs.digest }}"
+          touch "${{ runner.temp }}/digests/${digest#sha256:}"          
 
-      - name: Upload artifact
+      - name: Upload digest
         uses: actions/upload-artifact@v4
         with:
-          name: ${{ matrix.os}}.tar
-          path: ${{ runner.temp }}/image.tar
+          name: digests-${{ matrix.os }}
+          path: ${{ runner.temp }}/digests/*
+          if-no-files-found: error
           retention-days: 1
-
-  push:
+  
+  merge:
     runs-on: ubuntu-latest
-    needs: build
+    needs:
+      - build
     steps:
-      - name: Download artifacts
+      - name: Download digests
         uses: actions/download-artifact@v4
         with:
-          pattern: "ubuntu-*.tar"
-          path: images
+          path: ${{ runner.temp }}/digests
+          pattern: digests-*
+          merge-multiple: true
 
-      - name: Load image (arm)
+      - name: Log in to the Container registry
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+        
+
+      - name: Create manifest list and push
+        working-directory: ${{ runner.temp }}/digests
+        run: |
+          docker buildx imagetools create $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
+            $(printf '${{ env.REGISTRY }}/${{ env.IMAGE_NAME}}@sha256:%s ' *)          
+
+      - name: Inspect image
         run: |
-          docker load --input images/ubuntu-24.04-arm.tar
-          docker load --input images/ubuntu-24.04.tar
-          docker image ls -a
+          docker buildx imagetools inspect ${{ env.REGISTRY }}/${{ env.IMAGE_NAME}}:${{ steps.meta.outputs.version }}  
+
+  #     - name: Build Docker image
+  #       uses: docker/build-push-action@v6
+  #       with:
+  #         context: .
+  #         load: true
+  #         push: false
+  #         file: docker/Dockerfile
+  #         platforms: linux/${{ env.ARCH_TAG }}
+  #         tags: ${{ steps.meta.outputs.tags }}
+  #         labels: ${{ steps.meta.outputs.labels }}
+  #         outputs: type=docker, dest=${{ runner.temp }}/image.tar
+
+  #     - name: Upload artifact
+  #       uses: actions/upload-artifact@v4
+  #       with:
+  #         name: ${{ matrix.os}}
+  #         path: ${{ runner.temp }}/image.tar
+  #         retention-days: 1
+
+  # push:
+  #   runs-on: ubuntu-latest
+  #   needs: build
+  #   steps:
+  #     - name: Download artifacts
+  #       uses: actions/download-artifact@v4
+  #       with:
+  #         pattern: "ubuntu-*.tar"
+  #         path: images
+
+  #     - name: Load image (arm)
+  #       run: |
+  #         ls -l images/
+  #         # docker load --input images/ubuntu-24.04-arm.tar
+  #         # docker load --input images/ubuntu-24.04.tar
+  #         # docker image ls -a