RustPython

A Python-3 (CPython >= 3.14.0) Interpreter written in Rust :snake: :scream: :metal:.

Usage

Check out our online demo running on WebAssembly.

RustPython requires Rust latest stable version (e.g 1.67.1 at February 7th 2023). If you don't currently have Rust installed on your system you can do so by following the instructions at rustup.rs.

To check the version of Rust you're currently running, use rustc --version. If you wish to update, rustup update stable will update your Rust installation to the most recent stable release.

To build RustPython locally, first, clone the source code:

git clone https://github.com/RustPython/RustPython

RustPython uses symlinks to manage python libraries in Lib/. If on windows, running the following helps:

git config core.symlinks true

Then you can change into the RustPython directory and run the demo (Note: --release is needed to prevent stack overflow on Windows):

$ cd RustPython
$ cargo run --release demo_closures.py
Hello, RustPython!

Or use the interactive shell:

$ cargo run --release
Welcome to rustpython
>>>>> 2+2
4

NOTE: For windows users, please set RUSTPYTHONPATH environment variable as Lib path in project directory. (e.g. When RustPython directory is C:\RustPython, set RUSTPYTHONPATH as C:\RustPython\Lib)

You can also install and run RustPython with the following:

$ cargo install --git https://github.com/RustPython/RustPython rustpython
$ rustpython
Welcome to the magnificent Rust Python interpreter
>>>>>

venv

Because RustPython currently doesn't provide a well-packaged installation, using venv helps to use pip easier.

$ rustpython -m venv <your_env_name>
$ . <your_env_name>/bin/activate
$ python # now `python` is the alias of the RustPython for the new env

PIP

If you'd like to make https requests, you can enable the ssl feature, which also lets you install the pip package manager. Note that on Windows, you may need to install OpenSSL, or you can enable the ssl-vendor feature instead, which compiles OpenSSL for you but requires a C compiler, perl, and make. OpenSSL version 3 is expected and tested in CI. Older versions may not work.

Once you've installed rustpython with SSL support, you can install pip by running:

cargo install --git https://github.com/RustPython/RustPython
rustpython --install-pip

You can also install RustPython through the conda package manager, though this isn't officially supported and may be out of date:

conda install rustpython -c conda-forge
rustpython

SSL provider

For HTTPS requests, ssl-rustls feature is enabled by default. You can replace it with ssl-openssl feature if your environment requires OpenSSL. Note that to use OpenSSL on Windows, you may need to install OpenSSL, or you can enable the ssl-vendor feature instead, which compiles OpenSSL for you but requires a C compiler, perl, and make. OpenSSL version 3 is expected and tested in CI. Older versions may not work.

WASI

You can compile RustPython to a standalone WebAssembly WASI module so it can run anywhere.

Build

cargo build --target wasm32-wasip1 --no-default-features --features freeze-stdlib,stdlib --release

Run by wasmer

wasmer run --dir `pwd` -- target/wasm32-wasip1/release/rustpython.wasm `pwd`/extra_tests/snippets/stdlib_random.py

Run by wapm

$ wapm install rustpython
$ wapm run rustpython
>>>>> 2+2
4

Building the WASI file

You can build the WebAssembly WASI file with:

cargo build --release --target wasm32-wasip1 --features="freeze-stdlib"

Note: we use the freeze-stdlib to include the standard library inside the binary. You also have to run once rustup target add wasm32-wasip1.

JIT (Just in time) compiler

RustPython has a very experimental JIT compiler that compile python functions into native code.

Building

By default the JIT compiler isn't enabled, it's enabled with the jit cargo feature.

cargo run --features jit

This requires autoconf, automake, libtool, and clang to be installed.

Using

To compile a function, call __jit__() on it.

def foo():
    a = 5
    return 10 + a

foo.__jit__()  # this will compile foo to native code and subsequent calls will execute that native code
assert foo() == 15

Embedding RustPython into your Rust Applications

Interested in exposing Python scripting in an application written in Rust, perhaps to allow quickly tweaking logic where Rust's compile times would be inhibitive? Then examples/hello_embed.rs and examples/mini_repl.rs may be of some assistance.

Disclaimer

RustPython is in development, and while the interpreter certainly can be used in interesting use cases like running Python in WASM and embedding into a Rust project, do note that RustPython is not totally production-ready.

Contribution is more than welcome! See our contribution section for more information on this.

Conference videos

Checkout those talks on conferences:

• FOSDEM 2019
• EuroPython 2018

Use cases

Although RustPython is a fairly young project, a few people have used it to make cool projects:

• GreptimeDB: an open-source, cloud-native, distributed time-series database. Using RustPython for embedded scripting.
• pyckitup: a game engine written in rust.
• Robot Rumble: an arena-based AI competition platform
• Ruff: an extremely fast Python linter, written in Rust

Goals

• Full Python-3 environment entirely in Rust (not CPython bindings)
• A clean implementation without compatibility hacks

Documentation

Currently along with other areas of the project, documentation is still in an early phase.

You can read the online documentation for the latest release, or the user guide.

You can also generate documentation locally by running:

cargo doc # Including documentation for all dependencies
cargo doc --no-deps --all # Excluding all dependencies

Documentation HTML files can then be found in the target/doc directory or you can append --open to the previous commands to have the documentation open automatically on your default browser.

For a high level overview of the components, see the architecture document.

Contributing

Contributions are more than welcome, and in many cases we are happy to guide contributors through PRs or on Discord. Please refer to the development guide as well for tips on developments.

With that in mind, please note this project is maintained by volunteers, some of the best ways to get started are below:

Most tasks are listed in the issue tracker. Check issues labeled with good first issue if you wish to start coding.

To enhance CPython compatibility, try to increase unittest coverage by checking this article: How to contribute to RustPython by CPython unittest

Another approach is to checkout the source code: builtin functions and object methods are often the simplest and easiest way to contribute.

You can also simply run python -I scripts/whats_left.py to assist in finding any unimplemented method.

Compiling to WebAssembly

See this doc

Community

Chat with us on Discord.

Code of conduct

Our code of conduct can be found here.

Credit

The initial work was based on windelbouwman/rspython and shinglyu/RustPython

Links

These are some useful links to related projects:

• https://github.com/ProgVal/pythonvm-rust
• https://github.com/shinglyu/RustPython
• https://github.com/windelbouwman/rspython

License

This project is licensed under the MIT license. Please see the LICENSE file for more details.

The project logo is licensed under the CC-BY-4.0 license. Please see the LICENSE-logo file for more details.