Rules Rust

This repository provides rules for building Rust projects with Bazel.

Setup

The rules are released, and releases can be found on the GitHub Releases page. We recommend using the latest release from that page.

To use rules_rust in a project, add the following to your MODULE.bazel file:

bazel_dep(name = "rules_rust", version = "0.70.0")

Don't forget to substitute in your desired release's version number.

Specifying Rust version

To use a particular version of the Rust compiler, pass that version to the toolchain method of the rust extension, like this:

rust = use_extension("@rules_rust//rust:extensions.bzl", "rust")
rust.toolchain(
    edition = "2024",
    versions = [ "1.85.0" ],
)

As well as an exact version, versions can accept nightly/{iso_date} and beta/{iso_date} strings for toolchains from different release channels, as in

rust.toolchain(
    edition = "2021",
    versions = [ "nightly/1.85.0" ],
)

By default, a stable and nightly toolchain will be registered if no toolchain method is called (and thus no specific versions are registered). However, if only 1 version is passed and it is from the nightly or beta release channels (i.e. not stable), then the following build setting flag must be present, either on the command line or set in the project's .bazelrc file:

build --@rules_rust//rust/toolchain/channel=nightly

Failure to do so will result in rules attempting to match a stable toolchain when one was not registered, thus raising an error.

Supported bazel versions

The oldest version of Bazel the main branch is tested against is 7.4.1. Previous versions may still be functional in certain environments, but this is the minimum version we strive to fully support.

We test these rules against the latest rolling releases of Bazel, and aim for compatibility with them, but prioritise stable releases over rolling releases where necessary.

Supported platforms

We aim to support Linux and macOS.

We do not have sufficient maintainer expertise to support Windows. Most things probably work, but we have had to disable many tests in CI because we lack the expertise to fix them. We welcome contributions to help improve its support.