setuptoolsrust

Setuptools-rust is a Python packaging tool that enables building Rust extensions within setuptools-based projects. It provides a RustExtension class to describe a Python extension implemented in Rust and a RustBuildExt command that coordinates building the Rust code as part of the Python package build. The extension expects a Rust crate located at a specified path (typically a directory containing Cargo.toml) and produces a compiled shared library that Python can import as a module. The build backend is usually maturin when available, with a fallback to cargo if maturin is not installed. This arrangement allows developers to create Python packages that include performance-critical Rust components and distribute them as wheels or source distributions for multiple platforms.

Setuptools-rust targets crates that use bindings such as PyO3 or rust-cpython, but it can be used with any Rust code that can be exposed to Python as a Python extension module, provided the build backend can generate a suitable shared library. It integrates with the standard setuptools workflow, enabling Rust code to live alongside Python code in the same project and to participate in the usual packaging steps, including wheel building.

Usage typically involves declaring the Rust extension in setup.py via ext_modules and RustExtension, for example by specifying the module name and the path to the Rust crate. Optional parameters can control binding type (such as pyo3), cargo features, and other build flags. The path points to the directory containing Cargo.toml, and the build_ext step invokes maturin or cargo to compile the Rust portion and include the resulting library in the distribution. The project can also be configured through pyproject.toml in setups that use setuptools as a build backend.

Setuptools-rust is maintained to support the Python Rust ecosystem, aiming to simplify packaging of Rust-based Python extensions across platforms and Python versions.