ci: publish multi-platform preview images

.github/workflows/ci.yml

@@ -102,6 +102,8 @@ jobs:
     permissions:
       contents: read
       packages: write
+    outputs:
+      digest: ${{ steps.preview-build.outputs.digest }}
     steps:
       - uses: actions/checkout@v7
         if: "!env.ACT"
@@ -184,38 +186,132 @@ jobs:
           path: e2e/test-results/
           retention-days: 7
 
-      - name: Determine preview tag
+      - name: Log in to GHCR for preview publication
-        id: preview
         if: |
           !env.ACT &&
           (
             (github.event_name == 'pull_request' && github.event.pull_request.head.repo.full_name == github.repository) ||
             (github.event_name == 'workflow_dispatch' && inputs.operation == 'publish')
           )
-        env:
-          PR_NUMBER: ${{ github.event.pull_request.number || inputs.pr_number }}
-        run: echo "tag=pr-${PR_NUMBER}" >> "$GITHUB_OUTPUT"
-
-      - name: Log in to GHCR
-        if: steps.preview.outputs.tag != ''
         uses: docker/login-action@v4
         with:
           registry: ${{ env.REGISTRY }}
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
-      - name: Push preview image
+      - name: Push amd64 preview image by digest
-        if: steps.preview.outputs.tag != ''
+        id: preview-build
-        env:
+        if: |
-          PREVIEW_TAG: ${{ steps.preview.outputs.tag }}
+          !env.ACT &&
-        run: |
+          (
-          docker tag homarr-ci "${PREVIEW_IMAGE}:${PREVIEW_TAG}"
+            (github.event_name == 'pull_request' && github.event.pull_request.head.repo.full_name == github.repository) ||
-          docker push "${PREVIEW_IMAGE}:${PREVIEW_TAG}"
+            (github.event_name == 'workflow_dispatch' && inputs.operation == 'publish')
+          )
+        uses: docker/build-push-action@v7
+        with:
+          context: .
+          network: host
+          platforms: linux/amd64
+          outputs: type=image,"name=${{ env.PREVIEW_IMAGE }}",push-by-digest=true,name-canonical=true,push=true
+          cache-from: type=gha,scope=homarr-linux-amd64
+          secrets: |
+            TURBO_API=${{ secrets.TURBO_API }}
+            TURBO_TEAM=${{ secrets.TURBO_TEAM }}
+            TURBO_TOKEN=${{ secrets.TURBO_TOKEN }}
+            TURBO_REMOTE_CACHE_SIGNATURE_KEY=${{ secrets.TURBO_REMOTE_CACHE_SIGNATURE_KEY }}
 
       - name: Show Act publication result
         if: env.ACT
         run: echo "Act validated the publication path; external GHCR writes are disabled locally."
 
+  preview-arm64:
+    name: Build arm64 preview image
+    needs: fast-gate
+    if: |
+      (
+        (github.event_name == 'pull_request' && github.event.pull_request.head.repo.full_name == github.repository) ||
+        (github.event_name == 'workflow_dispatch' && inputs.operation == 'publish')
+      )
+    runs-on: ubuntu-24.04-arm
+    timeout-minutes: 20
+    permissions:
+      contents: read
+      packages: write
+    outputs:
+      digest: ${{ steps.preview-build.outputs.digest }}
+    steps:
+      - uses: actions/checkout@v7
+        if: "!env.ACT"
+        with:
+          persist-credentials: false
+          ref: ${{ github.event_name == 'workflow_dispatch' && inputs.ref || '' }}
+
+      - name: Log in to GHCR
+        if: "!env.ACT"
+        uses: docker/login-action@v4
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Set up Docker Buildx
+        if: "!env.ACT"
+        uses: docker/setup-buildx-action@v4
+
+      - name: Build and push arm64 preview image by digest
+        id: preview-build
+        if: "!env.ACT"
+        uses: docker/build-push-action@v7
+        with:
+          context: .
+          network: host
+          platforms: linux/arm64
+          outputs: type=image,"name=${{ env.PREVIEW_IMAGE }}",push-by-digest=true,name-canonical=true,push=true
+          cache-from: type=gha,scope=homarr-linux-arm64
+          cache-to: type=gha,scope=homarr-linux-arm64,mode=max
+          secrets: |
+            TURBO_API=${{ secrets.TURBO_API }}
+            TURBO_TEAM=${{ secrets.TURBO_TEAM }}
+            TURBO_TOKEN=${{ secrets.TURBO_TOKEN }}
+            TURBO_REMOTE_CACHE_SIGNATURE_KEY=${{ secrets.TURBO_REMOTE_CACHE_SIGNATURE_KEY }}
+
+  publish-preview:
+    name: Publish multi-platform preview image
+    needs: [container, preview-arm64]
+    if: |
+      (
+        (github.event_name == 'pull_request' && github.event.pull_request.head.repo.full_name == github.repository) ||
+        (github.event_name == 'workflow_dispatch' && inputs.operation == 'publish')
+      )
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    permissions:
+      packages: write
+    env:
+      PREVIEW_TAG: pr-${{ github.event.pull_request.number || inputs.pr_number }}
+    steps:
+      - name: Log in to GHCR
+        if: "!env.ACT"
+        uses: docker/login-action@v4
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Set up Docker Buildx
+        if: "!env.ACT"
+        uses: docker/setup-buildx-action@v4
+
+      - name: Publish preview manifest
+        if: "!env.ACT"
+        env:
+          AMD64_DIGEST: ${{ needs.container.outputs.digest }}
+          ARM64_DIGEST: ${{ needs.preview-arm64.outputs.digest }}
+        run: |
+          docker buildx imagetools create -t "${PREVIEW_IMAGE}:${PREVIEW_TAG}" \
+            "${PREVIEW_IMAGE}@${AMD64_DIGEST}" \
+            "${PREVIEW_IMAGE}@${ARM64_DIGEST}"
+
   cleanup:
     name: Clean up preview image
     if: github.event_name == 'pull_request_target' || (github.event_name == 'workflow_dispatch' && inputs.operation == 'cleanup')