Dockerfile

# Build the manager binary
FROM golang:1.23 as builder
ARG TARGETOS
ARG TARGETARCH

WORKDIR /workspace
# Copy the Go Modules manifests
COPY go.mod go.mod
COPY go.sum go.sum
# cache deps before building and copying source so that we don't need to re-download as much
# and so that source changes don't invalidate our downloaded layer
RUN go mod download

# Copy the go source
COPY main.go main.go
COPY api/ api/
COPY internal/ internal/

# 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.
ENV CGO_ENABLED=0
ENV GOOS=${TARGETOS:-linux}
ENV GOARCH=${TARGETARCH}
ENV GO111MODULE=on

# Do an initial compilation before setting the version so that there is less to
# re-compile when the version changes
RUN go build -mod=readonly ./...

ARG VERSION

# Build
RUN go build \
  -ldflags="-X=github.com/cert-manager/sample-external-issuer/internal/version.Version=${VERSION}" \
  -mod=readonly \
  -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:nonroot
WORKDIR /
COPY --from=builder /workspace/manager .
USER 65532:65532

ENTRYPOINT ["/manager"]