rust-musl-cross

Docker images for compiling static Rust binaries using musl-cross-make, inspired by rust-musl-builder

Prebuilt images

Currently we have the following prebuilt Docker images on Docker Hub.

Rust toolchain	Cross Compile Target	Docker Image Tag
stable	x86_64-unknown-linux-musl	x86_64-musl
stable	i686-unknown-linux-musl	i686-musl
stable	arm-unknown-linux-musleabi	arm-musleabi
stable	arm-unknown-linux-musleabihf	arm-musleabihf
stable	armv7-unknown-linux-musleabihf	armv7-musleabihf
stable	armv5te-unknown-linux-musleabi	armv5te-musleabi
stable	mips-unknown-linux-musl	mips-musl
stable	mipsel-unknown-linux-musl	mipsel-musl

To use armv7-unknown-linux-musleabihf target for example, first pull the image:

docker pull messense/rust-musl-cross:armv7-musleabihf

Then you can do:

alias rust-musl-builder='docker run --rm -it -v "$(pwd)":/home/rust/src messense/rust-musl-cross:armv7-musleabihf'
rust-musl-builder cargo build --release

This command assumes that $(pwd) is readable and writable. It will output binaries in armv7-unknown-linux-musleabihf. At the moment, it doesn't attempt to cache libraries between builds, so this is best reserved for making final release builds.

How it works

rust-musl-cross uses musl-libc, musl-gcc with the help of musl-cross-make to make it easy to compile, 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.

Making OpenSSL work

If your application uses OpenSSL, you will also need to take a few extra steps to make sure that it can find OpenSSL's list of trusted certificates, which is stored in different locations on different Linux distributions. You can do this using openssl-probe as follows:

extern crate openssl_probe;

fn main() {
    openssl_probe::init_ssl_cert_env_vars();
    //... your code
}

Use beta/nightly Rust

Currently we install stable Rust by default, if you want to switch to beta/nightly Rust, you can do it by extending from our Docker image, for example to use beta Rust for target x86_64-unknown-linux-musl:

FROM messense/rust-musl-cross:x86_64-musl
RUN rustup update beta && \
    rustup target add --toolchain beta x86_64-unknown-linux-musl

Strip binaries

You can use the musl-strip command inside the image to strip binaries, for example:

docker run --rm -it -v "$(pwd)":/home/rust/src messense/rust-musl-cross:armv7-musleabihf musl-strip /home/rust/src/target/release/example

License

Licensed under The MIT License