Dockerfile

# syntax=docker/dockerfile:1
FROM --platform=$BUILDPLATFORM golang:1.26 AS build
WORKDIR /src

COPY go.mod go.sum ./
RUN --mount=type=cache,target=/go/pkg/mod \
    --mount=type=cache,target=/root/.cache/go-build \
    go mod download

COPY . .
ARG TARGETOS
ARG TARGETARCH
RUN --mount=type=cache,target=/root/.cache/go-build \
    CGO_ENABLED=0 \
    GOOS=${TARGETOS:-linux} \
    GOARCH=${TARGETARCH:-amd64} \
    go build -trimpath -ldflags="-s -w" -o /out/k8s-copycat ./cmd/manager

FROM alpine:3.23 AS certs
RUN apk --no-cache add ca-certificates

FROM scratch
WORKDIR /
COPY --from=certs /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
COPY --from=build /out/k8s-copycat /k8s-copycat
USER 65532:65532
ENTRYPOINT ["/k8s-copycat"]