Dockerfile

ARG BUILDER_IMAGE=golang:1.23
ARG BASE_IMAGE=gcr.io/distroless/static:nonroot

# Build the manager binary
FROM --platform=${BUILDPLATFORM} ${BUILDER_IMAGE} AS builder
ARG TARGETOS
ARG TARGETARCH

WORKDIR /workspace
# cache deps before building so that we don't need to re-download as much
# and so that source changes don't invalidate our downloaded layer
COPY . .
RUN go mod download
# Build
# the GOARCH has not a default value to allow the binary be built according to the host where the command
# was called. For example, if we call make docker-build in a local env which has the Apple Silicon M1 SO
# the docker BUILDPLATFORM arg will be linux/arm64 when for Apple x86 it will be linux/amd64. Therefore,
# by leaving it empty we can ensure that the container and binary shipped on it will have the same platform.
RUN CGO_ENABLED=${CGO_ENABLED:-0} GOOS=${TARGETOS:-linux} GOARCH=${TARGETARCH} go build -a -o manager cmd/main.go

FROM --platform=${BUILDPLATFORM} ${BASE_IMAGE}
WORKDIR /
COPY --from=builder /workspace/manager .
USER 65532:65532

ENTRYPOINT ["/manager"]