Cross build for amd64 and arm64 platforms (#3)

.github/workflows/docker-publish.yml

@@ -30,9 +30,6 @@ jobs:
       # https://github.com/docker/setup-buildx-action
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
-        with:
-          # Only build for amd64 for now, we should extend to arm64 eventually
-          platforms: linux/amd64
 
       # Login against a Docker registry except on PR
       # https://github.com/docker/login-action
@@ -59,6 +56,7 @@ jobs:
         uses: docker/build-push-action@v5
         with:
           context: .
+          platforms: linux/amd64,linux/arm64
           push: ${{ github.event_name != 'pull_request' }}
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}

Dockerfile

@@ -1,18 +1,22 @@
-FROM golang:1.22.5-alpine3.19 AS builder
+# Use the $BUILDPLATFORM for the build stage
+FROM --platform=$BUILDPLATFORM golang:1.22.5-alpine3.19 AS builder
+
 WORKDIR /app
-RUN cat /etc/resolv.conf && apk add --no-cache git && \
-	git config --add --global url."[email protected]:".insteadOf https://github.com
 
 # Prepare dependencies
-COPY go.mod go.sum ./
+COPY go.mod go.sum .
 RUN go mod download
-# Build the binary
+
+# Copy the sources and config
 COPY ./cmd ./cmd
 COPY ./internal ./internal
 COPY ./config ./config
-RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o api ./cmd/api
 
+# Build the binary based on the target platform
+ARG TARGETOS TARGETARCH
+RUN CGO_ENABLED=0 GOOS=$TARGETOS GOARCH=$TARGETARCH go build -o api ./cmd/api
 
+# Use the $TARGETPLATFORM by default for the runtime stage
 FROM alpine:3.19
 WORKDIR /app
 COPY --from=builder /app/api ./api