FROM rust:1.94-bookworm AS builder
WORKDIR /build

# Build dependencies against stub sources so this layer is only invalidated by Cargo.toml/Cargo.lock changes.
COPY Cargo.toml Cargo.lock ./
RUN mkdir -p src/bin \
    && touch src/lib.rs \
    && echo 'fn main() {}' > src/bin/rust-bfdd.rs \
    && cargo build --release --locked --bin rust-bfdd \
    && rm -rf src

COPY src ./src
# COPY keeps the host mtimes, which may predate the stub build; force cargo to rebuild the crate itself.
RUN touch src/lib.rs src/bin/rust-bfdd.rs \
    && cargo build --release --locked --bin rust-bfdd

FROM debian:bookworm-slim
RUN useradd --system --no-create-home --shell /usr/sbin/nologin bfd \
    && mkdir -p /etc/rust-bfd/hooks.d
COPY --from=builder /build/target/release/rust-bfdd /usr/local/bin/rust-bfdd
USER bfd
EXPOSE 3784/udp
ENTRYPOINT ["/usr/local/bin/rust-bfdd"]