Rust app using build container and distroless

Turns out that, just like with Golang, it's really quite simple to craft a small container image for a Rust app. Taking a trivial "hello world" app using Actix, we can use a multi-stage build, and then one of the Google distroless container images as a base, to build a tiny final image. Dockerfile:

FROM rust:1.51 as builder
LABEL maintainer="yourname@whatever.com"

WORKDIR /app
COPY . /app
RUN cargo build --release

FROM gcr.io/distroless/cc-debian10
COPY --from=builder /app/target/release/hello-world /
EXPOSE 1111
CMD ["./hello-world"]

Don't forget to include a .dockerignore file at the same level as your Dockerfile (even if you're using podman/buildah - they will respect the .dockerignore). At a minimum, there's no need to include the git directories in the build context: .dockerignore

.git
target/

Finally, build your image:

docker build -t hello-world .

Although the build container (rust:1.51) is rather large, 1.27GB, and the intermediate images somehow balloon to 2.5GB, the final image is only ~30MB