PyO3
Rust bindings for Python. This includes running and interacting with Python code from a Rust binary, as well as writing native Python modules.
A comparison with rust-cpython can be found in the guide.
Usage
PyO3 supports Python 3.5 and up. The minimum required Rust version is 1.37.0-nightly 2019-07-19.
PyPy is also supported (via cpyext) for Python 3.5 only, targeted PyPy version is 7.0.0. Please refer to the pypy section.
You can either write a native Python module in Rust, or use Python from a Rust binary.
However, on some OSs, you need some additional packages. E.g. if you are on Ubuntu 18.04, please run
sudo apt install python3-dev python-dev
Using Rust from Python
PyO3 can be used to generate a native Python module.
Cargo.toml
[package]
name = "string-sum"
version = "0.1.0"
edition = "2018"
[lib]
name = "string_sum"
crate-type = ["cdylib"]
[dependencies.pyo3]
version = "0.8.2"
features = ["extension-module"]
src/lib.rs
# #![allow(unused_variables)] #fn main() { use pyo3::prelude::*; use pyo3::wrap_pyfunction; #[pyfunction] /// Formats the sum of two numbers as string fn sum_as_string(a: usize, b: usize) -> PyResult<String> { Ok((a + b).to_string()) } /// This module is a python module implemented in Rust. #[pymodule] fn string_sum(py: Python, m: &PyModule) -> PyResult<()> { m.add_wrapped(wrap_pyfunction!(sum_as_string))?; Ok(()) } #}
On Windows and Linux, you can build normally with cargo build --release
. On macOS, you need to set additional linker arguments. One option is to compile with cargo rustc --release -- -C link-arg=-undefined -C link-arg=dynamic_lookup
, the other is to create a .cargo/config
with the following content:
[target.x86_64-apple-darwin]
rustflags = [
"-C", "link-arg=-undefined",
"-C", "link-arg=dynamic_lookup",
]
For developing, you can copy and rename the shared library from the target folder: On MacOS, rename libstring_sum.dylib
to string_sum.so
, on Windows libstring_sum.dll
to string_sum.pyd
and on Linux libstring_sum.so
to string_sum.so
. Then open a Python shell in the same folder and you'll be able to import string_sum
.
To build, test and publish your crate as a Python module, you can use maturin or setuptools-rust. You can find an example for setuptools-rust in examples/word-count, while maturin should work on your crate without any configuration.
Using Python from Rust
Add pyo3
to your Cargo.toml
like this:
[dependencies]
pyo3 = "0.8.2"
Example program displaying the value of sys.version
and the current user name:
use pyo3::prelude::*; use pyo3::types::IntoPyDict; fn main() -> Result<(), ()> { let gil = Python::acquire_gil(); let py = gil.python(); main_(py).map_err(|e| { // We can't display python error type via ::std::fmt::Display, // so print error here manually. e.print_and_set_sys_last_vars(py); }) } fn main_(py: Python) -> PyResult<()> { let sys = py.import("sys")?; let version: String = sys.get("version")?.extract()?; let locals = [("os", py.import("os")?)].into_py_dict(py); let code = "os.getenv('USER') or os.getenv('USERNAME') or 'Unknown'"; let user: String = py.eval(code, None, Some(&locals))?.extract()?; println!("Hello {}, I'm Python {}", user, version); Ok(()) }
Our guide has a section with lots of examples about this topic.
Examples and tooling
- examples/word-count Counting the occurrences of a word in a text file
- hyperjson A hyper-fast Python module for reading/writing JSON data using Rust's serde-json
- rust-numpy Rust binding of NumPy C-API
- html-py-ever Using html5ever through kuchiki to speed up html parsing and css-selecting.
- pyo3-built Simple macro to expose metadata obtained with the
built
crate as aPyDict
- point-process High level API for pointprocesses as a Python library
- autopy A simple, cross-platform GUI automation library for Python and Rust.
- orjson Fast Python JSON library