How to Use Multi-Stage Docker Builds for Rust

Use a multi-stage Dockerfile with a builder stage to compile your Rust binary and a final stage to copy only the binary, excluding the toolchain and dependencies.

FROM rust:1.80-bookworm AS builder
WORKDIR /app
COPY . .
RUN cargo build --release

FROM debian:bookworm-slim
COPY --from=builder /app/target/release/my_binary /usr/local/bin/
CMD ["my_binary"]

Replace my_binary with the name of your binary found in target/release/ after running cargo build --release.

Multi-stage builds let you compile your Rust code in one environment and then copy only the finished program into a tiny, clean environment for running. This keeps your final Docker image small and secure by leaving out the heavy compiler and development tools. Think of it like baking a cake in a full kitchen but serving it on a small plate.