Dockerfile

ARG RUST_VERSION=1.84.0
ARG APP_NAME=rust-kubernetes-operator-example

# Build the controller binary.
FROM rust:${RUST_VERSION}-slim-bullseye AS build
ARG APP_NAME
WORKDIR /app

# Leverage a cache mount to /usr/local/cargo/registry/
# for downloaded dependencies and a cache mount to /app/target/ for
# compiled dependencies which will speed up subsequent builds.
# Leverage a bind mount to the src directory to avoid having to copy the
# source code into the container. Once built, copy the executable to an
# output directory before the cache mounted /app/target is unmounted.
RUN --mount=type=bind,source=src,target=src \
    --mount=type=bind,source=Cargo.toml,target=Cargo.toml \
    --mount=type=cache,target=/app/target/ \
    --mount=type=cache,target=/usr/local/cargo/registry/ \
    <<EOF
set -e
cargo build --release
cp ./target/release/$APP_NAME /bin/operator
EOF

# Build the controller image.
FROM debian:bullseye-slim AS final

# Create a non-privileged user that the app will run under.
ARG UID=10001
RUN adduser \
    --disabled-password \
    --gecos "" \
    --home "/nonexistent" \
    --shell "/sbin/nologin" \
    --no-create-home \
    --uid "${UID}" \
    operatoruser
USER operatoruser

# Copy the executable from the "build" stage.
COPY --from=build /bin/operator /bin/

# What the container should run when it is started.
CMD ["/bin/operator"]