add: multiarch docker image build (#1059)

.github/workflows/docker.yml

@@ -9,7 +9,7 @@ on:
       - "v?[0-9]+.[0-9]+.[0-9]+-dev.[0-9]+"
 #  pull_request:
 env:
-  PLATFORMS: linux/amd64
+  PLATFORMS: linux/amd64,linux/arm64
 jobs:
   docker:
     name: Docker

Dockerfile

@@ -1,5 +1,11 @@
 # Build the manager binary
-FROM golang:1.19 as builder
+FROM --platform=${BUILDPLATFORM:-linux/amd64} golang:1.19 as builder
+
+ARG BUILDPLATFORM
+ARG TARGETPLATFORM
+ARG TARGETOS
+ARG TARGETARCH
+RUN echo "BUILDPLATFORM: ${BUILDPLATFORM}, TARGETPLATFORM: ${TARGETPLATFORM}, TARGETOS: ${TARGETOS}, TARGETARCH: ${TARGETARCH}"
 
 WORKDIR /workspace
 # Copy the Go Modules manifests
@@ -18,11 +24,11 @@ COPY internal/ internal/
 COPY pkg/ pkg/
 
 # Build
-RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 GO111MODULE=on go build -a -o manager main.go
+RUN CGO_ENABLED=0 GOOS=${TARGETOS:-linux} GOARCH=${TARGETARCH:-amd64} GO111MODULE=on go build -a -o manager main.go
 
 # Use distroless as minimal base image to package the manager binary
 # Refer to https://github.com/GoogleContainerTools/distroless for more details
-FROM gcr.io/distroless/static-debian11:nonroot
+FROM --platform=${TARGETPLATFORM:-linux/amd64} gcr.io/distroless/static-debian11:nonroot
 WORKDIR /
 COPY --from=builder /workspace/manager .
 ENTRYPOINT ["/manager"]