From 34a1863eae878761999acd0ed5040cc3b6315af9 Mon Sep 17 00:00:00 2001
From: Paul Latzelsperger <paul.latzelsperger@beardyinc.com>
Date: Tue, 7 Jul 2026 16:27:16 +0200
Subject: [PATCH] feat(ci): improve multi-platform image build

Split the Docker publish workflow into per-platform build jobs (amd64 on
ubuntu-latest, arm64 on a native arm runner) that push by digest, plus a
merge job that assembles the multi-arch manifest. Tagging is now handled
by docker/metadata-action, all actions are pinned to commit SHAs, and
per-platform GHA build caches are used.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---
 .github/workflows/publish.yml | 128 ++++++++++++++++++++++++++++------
 1 file changed, 105 insertions(+), 23 deletions(-)

diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
index 372c9b5..225c829 100644
--- a/.github/workflows/publish.yml
+++ b/.github/workflows/publish.yml
@@ -8,44 +8,126 @@ on:
       - "*"
 
 env:
-  IMAGE: ghcr.io/eclipse-cfm/jwtlet
+  GHCR_IMAGE: ghcr.io/${{ github.repository }}
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 
 jobs:
-  publish:
-    runs-on: ubuntu-latest
+  build:
+    name: Build jwtlet for ${{ matrix.platform }}
+    runs-on: ${{ matrix.runner }}
     permissions:
       contents: read
       packages: write
 
+    strategy:
+      matrix:
+        include:
+          - platform: linux/amd64
+            runner: ubuntu-latest
+          - platform: linux/arm64
+            runner: ubuntu-24.04-arm
+
     steps:
-      - uses: actions/checkout@v4
+      - name: "Checkout code"
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
 
-      - name: Log in to GHCR
-        uses: docker/login-action@v3
+      - name: "Set up Docker Buildx"
+        uses: docker/setup-buildx-action@4d04d5d9486b7bd6fa91e7baf45bbb4f8b9deedd # v4.0.0
+
+      - name: "Log in to GitHub Container Registry"
+        uses: docker/login-action@4907a6ddec9925e35a0a9e82d7399ccc52663121 # v4.1.0
         with:
           registry: ghcr.io
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
-      - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3
+      - name: "Extract metadata"
+        id: meta
+        uses: docker/metadata-action@030e881283bb7a6894de51c315a6bfe6a94e05cf # v6.0.0
+        with:
+          images: ${{ env.GHCR_IMAGE }}
+          tags: |
+            type=ref,event=branch
+            type=ref,event=tag
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=sha
+            type=raw,value=latest,enable={{is_default_branch}}
 
-      - name: Determine tags
-        id: tags
-        run: |
-          if [[ "${{ github.ref_type }}" == "tag" ]]; then
-            echo "tags=${{ env.IMAGE }}:${{ github.ref_name }}" >> "$GITHUB_OUTPUT"
-          else
-            echo "tags=${{ env.IMAGE }}:${{ github.sha }},${{ env.IMAGE }}:latest" >> "$GITHUB_OUTPUT"
-          fi
-
-      - name: Build and push
-        uses: docker/build-push-action@v6
+      - name: "Build and push Docker image"
+        id: build
+        uses: docker/build-push-action@bcafcacb16a39f128d818304e6c9c0c18556b85f #v7.1.0
         with:
+          platforms: ${{ matrix.platform }}
+          labels: ${{ steps.meta.outputs.labels }}
           context: .
           file: crates/jwtlet-server/Dockerfile
           push: true
-          platforms: linux/amd64,linux/arm64
-          tags: ${{ steps.tags.outputs.tags }}
-          cache-from: type=gha
-          cache-to: type=gha,mode=max
+          outputs: type=image,name=${{ env.GHCR_IMAGE }},push-by-digest=true,name-canonical=true,push=true,oci-mediatypes=true
+          cache-from: type=gha,scope=${{ matrix.platform == 'linux/amd64' && 'amd64' || 'arm64' }}
+          cache-to: type=gha,scope=${{ matrix.platform == 'linux/amd64' && 'amd64' || 'arm64' }},mode=max
+      - name: Export digest
+        run: |
+          mkdir -p /tmp/digests
+          digest="${{ steps.build.outputs.digest }}"
+          touch "/tmp/digests/${digest#sha256:}"
+
+      - name: Upload digest
+        uses: actions/upload-artifact@bbbca2ddaa5d8feaa63e36b76fdaad77386f024f #v7.0.0
+        with:
+          name: digest-${{ matrix.platform == 'linux/amd64' && 'amd64' || 'arm64' }}
+          path: /tmp/digests/*
+          if-no-files-found: error
+          retention-days: 1
+
+  merge:
+    name: Merge jwtlet Docker Manifests
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+
+    needs:
+      - build
+
+    steps:
+      - name: Download digests
+        uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
+        with:
+          path: /tmp/digests
+          pattern: digest-*
+          merge-multiple: true
+
+      - name: "Set up Docker Buildx"
+        uses: docker/setup-buildx-action@4d04d5d9486b7bd6fa91e7baf45bbb4f8b9deedd # v4.0.0
+
+      - name: "Extract metadata"
+        id: meta
+        uses: docker/metadata-action@030e881283bb7a6894de51c315a6bfe6a94e05cf # v6.0.0
+        with:
+          images: ${{ env.GHCR_IMAGE }}
+          tags: |
+            type=ref,event=branch
+            type=ref,event=tag
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=sha
+            type=raw,value=latest,enable={{is_default_branch}}
+
+      - name: "Log in to GitHub Container Registry"
+        uses: docker/login-action@4907a6ddec9925e35a0a9e82d7399ccc52663121 # v4.1.0
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Create and push manifest
+        working-directory: /tmp/digests
+        run: |
+          docker buildx imagetools create \
+            $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
+            $(printf '${{ env.GHCR_IMAGE }}@sha256:%s ' *)