Switched to using GHA artifacts for PRs from forks

Author: cmraible

.github/workflows/docker-build.yml

@@ -57,6 +57,22 @@ jobs:
             org.opencontainers.image.vendor=TryGhost
             maintainer=TryGhost
 
+      - name: Determine build strategy
+        id: strategy
+        run: |
+          IS_FORK_PR="false"
+          if [ "${{ github.event_name }}" = "pull_request" ] && [ "${{ github.event.pull_request.head.repo.full_name }}" != "${{ github.repository }}" ]; then
+            IS_FORK_PR="true"
+          fi
+          echo "is-fork-pr=$IS_FORK_PR" >> $GITHUB_OUTPUT
+          echo "should-push=${{ github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name == github.repository }}" >> $GITHUB_OUTPUT
+          echo "should-load=$IS_FORK_PR" >> $GITHUB_OUTPUT
+          
+          echo "Build strategy determined:"
+          echo "- Is fork PR: $IS_FORK_PR"
+          echo "- Should push: ${{ github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name == github.repository }}"
+          echo "- Should load: $IS_FORK_PR"
+
       - name: Display Docker metadata
         run: |
           echo "Generated tags:"
@@ -72,9 +88,9 @@ jobs:
           context: .
           file: .docker/Dockerfile
           # Only push on main branch or PRs from the main repo (not forks)
-          push: ${{ github.event_name != 'pull_request' || (github.event_name == 'pull_request' && github.event.pull_request.head.repo.full_name == github.repository) }}
+          push: ${{ steps.strategy.outputs.should-push }}
           # Only load image on PRs from forks (to allow testing without pushing)
-          load: ${{ github.event_name == 'pull_request' && github.event.pull_request.head.repo.full_name != github.repository }}
+          load: ${{ steps.strategy.outputs.should-load }}
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}
           # On PRs: use both main cache and PR-specific cache
@@ -83,12 +99,29 @@ jobs:
             type=registry,ref=${{ steps.cache.outputs.image }}:cache-main
             ${{ github.event_name == 'pull_request' && format('type=registry,ref={0}:cache-pr-{1}', steps.cache.outputs.image, github.event.pull_request.number) || '' }}
           # Only export cache if we can push (not on fork PRs)
-          cache-to: ${{ (github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name == github.repository) && format('type=registry,ref={0}:cache-{1},mode=max', steps.cache.outputs.image, github.event_name == 'pull_request' && format('pr-{0}', github.event.pull_request.number) || 'main') || '' }}
+          cache-to: ${{ steps.strategy.outputs.should-push == 'true' && format('type=registry,ref={0}:cache-{1},mode=max', steps.cache.outputs.image, github.event_name == 'pull_request' && format('pr-{0}', github.event.pull_request.number) || 'main') || '' }}
+
+      - name: Save image as artifact (fork PR)
+        if: steps.strategy.outputs.is-fork-pr == 'true'
+        run: |
+          IMAGE_TAG=$(echo "${{ steps.meta.outputs.tags }}" | head -n1)
+          echo "Saving image: $IMAGE_TAG"
+          docker save "$IMAGE_TAG" | gzip > docker-image.tar.gz
+          echo "Image saved as docker-image.tar.gz"
+          ls -lh docker-image.tar.gz
+
+      - name: Upload image artifact (fork PR)
+        if: steps.strategy.outputs.is-fork-pr == 'true'
+        uses: actions/upload-artifact@v4
+        with:
+          name: docker-image
+          path: docker-image.tar.gz
+          retention-days: 1
 
     outputs:
       image-tags: ${{ steps.meta.outputs.tags }}
       image-digest: ${{ steps.build.outputs.digest }}
-      is-fork: ${{ github.event_name == 'pull_request' && github.event.pull_request.head.repo.full_name != github.repository }}
+      is-fork: ${{ steps.strategy.outputs.is-fork-pr }}
   test:
     needs: build
     runs-on: ubuntu-latest-16-cores
@@ -97,6 +130,20 @@ jobs:
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
 
+      - name: Download image artifact (fork PR)
+        if: needs.build.outputs.is-fork == 'true'
+        uses: actions/download-artifact@v4
+        with:
+          name: docker-image
+
+      - name: Load image from artifact (fork PR)
+        if: needs.build.outputs.is-fork == 'true'
+        run: |
+          echo "Loading Docker image from artifact..."
+          gunzip -c docker-image.tar.gz | docker load
+          echo "Available images after load:"
+          docker images
+
       - name: Log in to GitHub Container Registry
         if: needs.build.outputs.is-fork == 'false'
         uses: docker/login-action@v3
@@ -119,21 +166,26 @@ jobs:
           echo "Pulling image from registry..."
           docker pull ${{ steps.image.outputs.tag }}
 
-      - name: List available images (fork PR)
-        if: needs.build.outputs.is-fork == 'true'
-        run: |
-          echo "Images loaded locally:"
-          docker images
-          echo "Looking for image: ${{ steps.image.outputs.tag }}"
-
       - name: Verify image is available
         run: |
-          if docker inspect ${{ steps.image.outputs.tag }} > /dev/null 2>&1; then
-            echo "✅ Image ${{ steps.image.outputs.tag }} is available"
+          IMAGE_TAG="${{ steps.image.outputs.tag }}"
+          echo "Checking for image: $IMAGE_TAG"
+          
+          if docker inspect "$IMAGE_TAG" > /dev/null 2>&1; then
+            echo "✅ Image $IMAGE_TAG is available"
+            echo "Image details:"
+            docker inspect "$IMAGE_TAG" --format='{{.Id}} {{.Created}}'
           else
-            echo "❌ Image ${{ steps.image.outputs.tag }} is not available"
+            echo "❌ Image $IMAGE_TAG is not available"
             echo "Available images:"
             docker images
+            
+            # For fork PRs, the image might have been loaded with a different tag
+            if [ "${{ needs.build.outputs.is-fork }}" = "true" ]; then
+              echo ""
+              echo "Searching for any loaded Ghost images..."
+              docker images --format "table {{.Repository}}:{{.Tag}}\t{{.ID}}\t{{.CreatedAt}}" | grep -E "(ghost|Ghost)" || echo "No Ghost images found"
+            fi
             exit 1
           fi