build(ci): optimise docker builds (#83)

.github/workflows/release.yml

@@ -25,6 +25,10 @@ concurrency:
   group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
   cancel-in-progress: true
 
+env:
+  REGISTRY: ghcr.io
+  REGISTRY_IMAGE: ghcr.io/${{ github.repository }}
+
 permissions:
   contents: write
   packages: write
@@ -96,6 +100,17 @@ jobs:
     name: Build Docker images
     runs-on: ubuntu-latest
     needs: test
+    strategy:
+      fail-fast: true
+      matrix:
+        platform:
+          - linux/386
+          - linux/amd64
+          - linux/amd64/v2
+          - linux/amd64/v3
+          - linux/arm/v6
+          - linux/arm/v7
+          - linux/arm64
     steps:
       - name: Checkout
         uses: actions/checkout@v4
@@ -105,15 +120,15 @@ jobs:
       - name: Login to GitHub Container Registry
         uses: docker/login-action@v3
         with:
-          registry: ghcr.io
+          registry: ${{ env.REGISTRY }}
           username: ${{ github.repository_owner }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Extract metadata
         id: meta
         uses: docker/metadata-action@v5
         with:
-          images: ghcr.io/nuxencs/seasonpackarr
+          images: ${{ env.REGISTRY_IMAGE }}
           tags: |
             type=semver,pattern={{version}},prefix=v
             type=semver,pattern={{major}}.{{minor}},prefix=v
@@ -128,15 +143,17 @@ jobs:
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
 
+      - name: Supported Architectures
+        run: docker buildx ls
+
       - name: Build and publish image
         id: docker_build
         uses: docker/build-push-action@v5
         with:
           context: .
           file: ./ci.Dockerfile
-          platforms: linux/amd64,linux/arm/v7,linux/arm64/v8
-          push: ${{ github.event.pull_request.head.repo.full_name == 'nuxencs/seasonpackarr' || github.event_name != 'pull_request' }}
-          tags: ${{ steps.meta.outputs.tags }}
+          platforms: ${{ matrix.platform }}
+          outputs: type=image,name=${{ env.REGISTRY_IMAGE }},push-by-digest=true,name-canonical=true,push=${{ (github.event.pull_request.head.repo.full_name == github.repository || github.event_name != 'pull_request') && 'true' || 'false' }}
           labels: ${{ steps.meta.outputs.labels }}
           build-args: |
             BUILDTIME=${{ fromJSON(steps.meta.outputs.json).labels['org.opencontainers.image.created'] }}
@@ -146,5 +163,64 @@ jobs:
           cache-to: type=gha,mode=max
           provenance: false
 
-      - name: Image digest
-        run: echo ${{ steps.docker_build.outputs.digest }}
+      - name: Export image digest
+        id: digest-prep
+        run: |
+          mkdir -p /tmp/digests
+          digest="${{ steps.docker_build.outputs.digest }}"
+          echo "manifest-hash=${digest#sha256:}" >> "$GITHUB_OUTPUT"
+          touch "/tmp/digests/${digest#sha256:}"
+
+      - name: Upload image digest
+        uses: actions/upload-artifact@v4
+        with:
+          name: docker-digests-${{ steps.digest-prep.outputs.manifest-hash }}
+          path: /tmp/digests/*
+          if-no-files-found: error
+          retention-days: 1
+
+  docker-merge:
+    name: Publish Docker multi-arch manifest
+    if: ${{ github.event.pull_request.head.repo.full_name == github.repository || github.event_name != 'pull_request' }}
+    runs-on: ubuntu-latest
+    needs: [docker, test]
+    steps:
+      - name: Download image digests
+        uses: actions/download-artifact@v4
+        with:
+          path: /tmp/digests
+          pattern: docker-digests-*
+          merge-multiple: true
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Login to GitHub Container Registry
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract metadata
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ${{ env.REGISTRY_IMAGE }}
+          tags: |
+            type=semver,pattern={{version}},prefix=v
+            type=semver,pattern={{major}}.{{minor}},prefix=v
+            type=ref,event=branch
+            type=ref,event=pr
+          flavor: |
+            latest=auto
+
+      - name: Create manifest list and push
+        working-directory: /tmp/digests
+        run: |
+          docker buildx imagetools create $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
+            $(printf '${{ env.REGISTRY_IMAGE }}@sha256:%s ' *)
+
+      - name: Inspect image
+        run: |
+          docker buildx imagetools inspect ${{ env.REGISTRY_IMAGE }}:${{ steps.meta.outputs.version }}

ci.Dockerfile

@@ -6,17 +6,22 @@ WORKDIR /src
 ARG VERSION=dev \
     REVISION=dev \
     BUILDTIME \
-    TARGETOS TARGETARCH
+    TARGETOS TARGETARCH TARGETVARIANT
 
 COPY go.mod go.sum ./
 RUN go mod download
 COPY . ./
 
 # build seasonpackarr
 FROM --platform=$BUILDPLATFORM app-base AS seasonpackarr
-
-RUN --mount=target=. \
-    GOOS=$TARGETOS GOARCH=$TARGETARCH go build -ldflags "-s -w -X main.version=${VERSION} -X main.commit=${REVISION} -X main.date=${BUILDTIME}" -o /out/bin/seasonpackarr cmd/seasonpackarr/main.go
+RUN --network=none --mount=target=. \
+export GOOS=$TARGETOS; \
+export GOARCH=$TARGETARCH; \
+[[ "$GOARCH" == "amd64" ]] && export GOAMD64=$TARGETVARIANT; \
+[[ "$GOARCH" == "arm" ]] && [[ "$TARGETVARIANT" == "v6" ]] && export GOARM=6; \
+[[ "$GOARCH" == "arm" ]] && [[ "$TARGETVARIANT" == "v7" ]] && export GOARM=7; \
+echo $GOARCH $GOOS $GOARM$GOAMD64; \
+go build -ldflags "-s -w -X main.version=${VERSION} -X main.commit=${REVISION} -X main.date=${BUILDTIME}" -o /out/bin/seasonpackarr cmd/seasonpackarr/main.go
 
 # build runner
 FROM alpine:latest as RUNNER