ci: native multi-arch publish (amd64 + arm64)

.github/workflows/publish-image.yml

@@ -10,22 +10,71 @@ permissions:
   contents: read
   packages: write
 
+# Native multi-arch: each (image, arch) builds on a native runner (no QEMU),
+# pushes by digest, then a merge job stitches the per-arch digests into one
+# multi-arch manifest per image. amd64 on ubuntu-latest, arm64 on the native
+# ubuntu-24.04-arm runner.
 jobs:
-  publish:
-    runs-on: ubuntu-latest
+  build:
+    runs-on: ${{ matrix.runner }}
     strategy:
       fail-fast: false
       matrix:
         include:
-          - image: tidebase
-            dockerfile: apps/server/Dockerfile
-          - image: tidebase-mcp
-            dockerfile: apps/mcp/Dockerfile
+          - { image: tidebase, dockerfile: apps/server/Dockerfile, platform: linux/amd64, arch: amd64, runner: ubuntu-latest }
+          - { image: tidebase, dockerfile: apps/server/Dockerfile, platform: linux/arm64, arch: arm64, runner: ubuntu-24.04-arm }
+          - { image: tidebase-mcp, dockerfile: apps/mcp/Dockerfile, platform: linux/amd64, arch: amd64, runner: ubuntu-latest }
+          - { image: tidebase-mcp, dockerfile: apps/mcp/Dockerfile, platform: linux/arm64, arch: arm64, runner: ubuntu-24.04-arm }
     steps:
       - uses: actions/checkout@v4
 
       - uses: docker/setup-buildx-action@v3
 
+      - uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - id: build
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          file: ${{ matrix.dockerfile }}
+          platforms: ${{ matrix.platform }}
+          outputs: type=image,name=ghcr.io/blueprintlabio/${{ matrix.image }},push-by-digest=true,name-canonical=true,push=true
+          cache-from: type=gha,scope=${{ matrix.image }}-${{ matrix.arch }}
+          cache-to: type=gha,mode=max,scope=${{ matrix.image }}-${{ matrix.arch }}
+
+      - name: Export digest
+        run: |
+          mkdir -p "${{ runner.temp }}/digests"
+          digest="${{ steps.build.outputs.digest }}"
+          touch "${{ runner.temp }}/digests/${digest#sha256:}"
+
+      - uses: actions/upload-artifact@v4
+        with:
+          # `--` delimiter so `tidebase` does not prefix-match `tidebase-mcp`.
+          name: digests-${{ matrix.image }}--${{ matrix.arch }}
+          path: ${{ runner.temp }}/digests/*
+          if-no-files-found: error
+          retention-days: 1
+
+  merge:
+    needs: build
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        image: [tidebase, tidebase-mcp]
+    steps:
+      - uses: actions/download-artifact@v4
+        with:
+          path: ${{ runner.temp }}/digests
+          pattern: digests-${{ matrix.image }}--*
+          merge-multiple: true
+
+      - uses: docker/setup-buildx-action@v3
+
       - uses: docker/login-action@v3
         with:
           registry: ghcr.io
@@ -37,19 +86,16 @@ jobs:
         with:
           images: ghcr.io/blueprintlabio/${{ matrix.image }}
           tags: |
-            type=ref,event=tag
             type=raw,value=latest,enable={{is_default_branch}}
             type=sha
+            type=ref,event=tag
 
-      - uses: docker/build-push-action@v6
-        with:
-          context: .
-          file: ${{ matrix.dockerfile }}
-          # amd64 only: matches the deploy target (Coolify host) and builds
-          # natively on the GitHub runner. Native arm64 is added separately.
-          platforms: linux/amd64
-          push: true
-          tags: ${{ steps.meta.outputs.tags }}
-          labels: ${{ steps.meta.outputs.labels }}
-          cache-from: type=gha,scope=${{ matrix.image }}
-          cache-to: type=gha,mode=max,scope=${{ matrix.image }}
+      - name: Create multi-arch manifest
+        working-directory: ${{ runner.temp }}/digests
+        run: |
+          docker buildx imagetools create \
+            $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
+            $(printf 'ghcr.io/blueprintlabio/${{ matrix.image }}@sha256:%s ' *)
+
+      - name: Inspect
+        run: docker buildx imagetools inspect ghcr.io/blueprintlabio/${{ matrix.image }}:${{ steps.meta.outputs.version }}