platten / rust-musl-builder

Docker images for compiling static Rust binaries using musl-libc and musl-gcc, with static version of OpenSSL.

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

• Source on GitHub

However, rustls now works well with most of the Rust ecosystem, including reqwest, tokio and many others.

• See if you can switch away from OpenSSL, typically by using features in Cargo.toml to ask your dependencies to use rustls instead.
• If you don't need OpenSSL, try cross build --target=x86_64-unknown-linux-musl --release to cross-compile your binaries for libmusl. This supports many more platforms, with less hassle!

What is this?

This image allows you to build static Rust binaries using openssl. These images can be distributed as single executable files with no dependencies, and they should work on any modern Linux system.

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 make static release binaries using TravisCI and GitHub, or you can copy your Rust application into an Alpine Linux container. See below for details!

How it works

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

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

Development notes

After modifying the image, run ./test-image to make sure that everything works.

Other ways to build portable Rust binaries

If for some reason this image doesn't meet your needs, there's a variety of other people working on similar projects:

• messense/rust-musl-cross shows how to build binaries for many different architectures.
• japaric/rust-cross has extensive instructions on how to cross-compile Rust applications.
• clux/muslrust also supports libcurl.
• golddranks/rust_musl_docker. Another Docker image.

License

Either the Apache 2.0 license, or the MIT license.