rust-musl-builder/README.md

rust-musl-builder: Docker container for easily building static Rust binaries

Do you want to compile a completely static Rust binary with no external dependencies? If so, try:

alias rust-musl-builder='docker run --rm -it -v "$(pwd)":/home/rust/src ekidd/rust-musl-builder'
rust-musl-builder cargo build --rebase

This command assumes that $(pwd) is readable and writable by uid 1000, gid 1000. It will output binaries in target/x86_64-unknown-linux-musl/release. At the moment, it doesn't attempt to cache libraries between builds, so this is best reserved for making final release builds.

Deploying your Rust application

With a bit of luck, you should be able to just copy your application binary from target/x86_64-unknown-linux-musl/release, and install it directly on any reasonably modern x86_64 Linux machine. In particular, you should be able to copy your Rust application into an Alpine Linux container.

How it works

rust-musl-builder uses musl-libc, musl-gcc, and the new rustup target support. It includes static versions of several libraries:

• The standard musl-libc libraries.
• OpenSSL, which is needed by many Rust applications.

Adding more C libraries

If you're using Docker crates which require specific C libraries to be installed, you can create a Dockerfile based on this one, and use musl-gcc to compile the libraries you need. For example:

FROM ekidd/rust-musl-builder:stable

RUN VERS=1.2.8 && \
    mkdir -p /home/rust/libs && cd /home/rust/libs && \
    curl -LO http://zlib.net/zlib-$VERS.tar.gz && \
    tar xzf zlib-$VERS.tar.gz && cd zlib-$VERS && \
    CC=musl-gcc ./configure --static --prefix=/usr/local/musl && \
    make && sudo make install && \
    rm -rf /home/rust/libs/zlib-$VERS.tar.gz /home/rust/libs/zlib-$VERS

This usually involves a bit of experimentation for each new library, but it seems to work well for most simple, standalone libraries.

If you need an especially common library, please feel free to submit a pull request adding it to the main Dockerfile! We'd like to support popular Rust crates out of the box.