ci: use Go cross-compilation to eliminate slow arm64 runner

.github/workflows/docker.yml

@@ -14,22 +14,10 @@ env:
 
 jobs:
   build:
-    name: Build (${{ matrix.platform }})
-    runs-on: ${{ matrix.runner }}
+    runs-on: ubuntu-latest
     permissions:
       contents: read
       packages: write
-    outputs:
-      digest-amd64: ${{ steps.digest.outputs.digest-linux-amd64 }}
-      digest-arm64: ${{ steps.digest.outputs.digest-linux-arm64 }}
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - platform: linux/amd64
-            runner: ubuntu-latest
-          - platform: linux/arm64
-            runner: ubuntu-24.04-arm
 
     steps:
       - name: Checkout
@@ -39,6 +27,11 @@ jobs:
         id: image
         run: echo "name=$(echo '${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}' | tr '[:upper:]' '[:lower:]')" >> "$GITHUB_OUTPUT"
 
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+        with:
+          platforms: arm64
+
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
 
@@ -50,74 +43,6 @@ jobs:
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
-      - name: Extract metadata
-        id: meta
-        uses: docker/metadata-action@v5
-        with:
-          images: ${{ steps.image.outputs.name }}
-
-      - name: Build and push by digest
-        id: build
-        uses: docker/build-push-action@v6
-        with:
-          context: .
-          platforms: ${{ matrix.platform }}
-          push: ${{ github.event_name != 'pull_request' }}
-          labels: ${{ steps.meta.outputs.labels }}
-          outputs: type=image,name=${{ steps.image.outputs.name }},push-by-digest=true,name-canonical=true,push=${{ github.event_name != 'pull_request' }}
-          cache-from: type=gha,scope=${{ matrix.platform }}
-          cache-to: type=gha,mode=max,scope=${{ matrix.platform }}
-          provenance: false
-
-      - name: Export digest
-        if: github.event_name != 'pull_request'
-        id: digest
-        run: |
-          PLATFORM_SAFE=$(echo "${{ matrix.platform }}" | tr '/' '-')
-          echo "digest-${PLATFORM_SAFE}=${{ steps.build.outputs.digest }}" >> "$GITHUB_OUTPUT"
-          mkdir -p /tmp/digests
-          echo "${{ steps.build.outputs.digest }}" > "/tmp/digests/${PLATFORM_SAFE}.txt"
-
-      - name: Upload digest artifact
-        if: github.event_name != 'pull_request'
-        uses: actions/upload-artifact@v4
-        with:
-          name: digest-${{ matrix.runner }}
-          path: /tmp/digests/
-          if-no-files-found: error
-          retention-days: 1
-
-  merge:
-    name: Merge manifests
-    runs-on: ubuntu-latest
-    if: github.event_name != 'pull_request'
-    needs: build
-    permissions:
-      contents: read
-      packages: write
-
-    steps:
-      - name: Download digests
-        uses: actions/download-artifact@v4
-        with:
-          pattern: digest-*
-          path: /tmp/digests
-          merge-multiple: true
-
-      - name: Set lowercase image name
-        id: image
-        run: echo "name=$(echo '${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}' | tr '[:upper:]' '[:lower:]')" >> "$GITHUB_OUTPUT"
-
-      - 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.actor }}
-          password: ${{ secrets.GITHUB_TOKEN }}
-
       - name: Extract metadata
         id: meta
         uses: docker/metadata-action@v5
@@ -130,12 +55,15 @@ jobs:
             type=semver,pattern={{major}}.{{minor}}
             type=sha,prefix=
 
-      - name: Create and push manifest
-        run: |
-          DIGESTS=$(find /tmp/digests -name '*.txt' -exec cat {} \; | xargs -I{} echo "${{ steps.image.outputs.name }}@{}")
-          TAGS=$(echo "${{ steps.meta.outputs.tags }}" | xargs -I{} echo "--tag {}")
-          docker buildx imagetools create $TAGS $DIGESTS
+      - name: Build and push
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          platforms: linux/amd64,linux/arm64
+          push: ${{ github.event_name != 'pull_request' }}
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+          provenance: false
 
-      - name: Inspect manifest
-        run: |
-          docker buildx imagetools inspect ${{ steps.image.outputs.name }}:${{ steps.meta.outputs.version }}

Dockerfile

@@ -1,4 +1,8 @@
-FROM golang:1.21-alpine AS builder
+# builder 阶段始终运行在构建机原生平台（amd64），用 Go 交叉编译目标平台二进制
+FROM --platform=$BUILDPLATFORM golang:1.21-alpine AS builder
+
+ARG TARGETOS
+ARG TARGETARCH
 
 WORKDIR /app
 COPY go.mod go.sum ./
@@ -8,7 +12,7 @@ RUN --mount=type=cache,target=/go/pkg/mod \
 COPY . .
 RUN --mount=type=cache,target=/go/pkg/mod \
     --mount=type=cache,target=/root/.cache/go-build \
-    CGO_ENABLED=0 GOOS=linux go build -o kiro-go .
+    CGO_ENABLED=0 GOOS=${TARGETOS} GOARCH=${TARGETARCH} go build -o kiro-go .
 
 FROM alpine:latest
 RUN apk --no-cache add ca-certificates