Pyo3-pack

Build and publish crates with pyo3, rust-cpython and cffi bindings as well as rust binaries as python packages.

This project was meant as a zero configuration replacement for setuptools-rust. It supports building wheels for python 2.7 and 3.5+ on windows, linux and mac and can upload them to pypi.

Usage

You can either download binaries from the latest release or install it with pip:

pip install pyo3-pack

You can also install pyo3-pack from source, though it's an older version:

cargo install pyo3-pack

There are three main subcommands:

• publish builds the crate into python packages and publishes them to pypi.
• build builds the wheels and stores them in a folder (target/wheels by default), but doesn't upload them.
• develop builds the crate and install it's as a python module directly in the current virtualenv

pyo3 and rust-cpython bindings are automatically detected, for cffi or binaries you need to pass -b cffi or -b bin. pyo3-pack needs no extra configuration files, and also doesn't clash with an existing setuptools-rust or milksnake configuration. You can even integrate it with testing tools such as tox (see get-fourtytwo for an example).

The name of the package will be the name of the cargo project, i.e. the name field in the [package] section of Cargo.toml. The name of the module, which you are using when importing, will be the name value in the [lib] section (which defaults to the name of the package). For binaries it's simply the name of the binary generated by cargo.

Pip allows adding so called console scripts, which are shell commands that execute some function in you program. You can add console scripts in a section [package.metadata.pyo3-pack.scripts]. The keys are the script names while the values are the path to the function in the format some.module.path:class.function, where the class part is optional. The function is called with no arguments. Example:

[package.metadata.pyo3-pack.scripts]
get_42 = "get_fourtytwo:DummyClass.get_42"

You can also specify trove classifiers in your Cargo.toml under package.metadata.pyo3-pack.classifier, e.g.:

[package.metadata.pyo3-pack]
classifier = ["Programming Language :: Python"]

pyo3 and rust-cpython

For pyo3 and rust-cpython, pyo3-pack can only build packages for installed python versions. On linux and mac, all python versions in PATH are used. If you don't set your own interpreters with -i, a heuristic is used to search for python installations. On windows all versions from the python launcher (which is installed by default by the python.org installer) and all conda environments except base are used. You can check which versions are picked up with the list-python subcommand.

Cffi

Cffi wheels are compatible with all python versions, but they need to have cffi installed for the python used for building (pip install cffi).

pyo3-pack will run cbindgen and generate cffi bindings. You can override this with a build script that writes a header to target/header.h.

use cbindgen; // Use `extern crate cbindgen` in rust 2015
use std::env;
use std::path::Path;

fn main() {
    let crate_dir = env::var("CARGO_MANIFEST_DIR").unwrap();

    let bindings = cbindgen::Builder::new()
        .with_no_includes()
        .with_language(cbindgen::Language::C)
        .with_crate(crate_dir)
        .generate()
        .unwrap();
    bindings.write_to_file(Path::new("target").join("header.h"));
}

Manylinux and auditwheel

For portability reasons, native python modules on linux must only dynamically link a set of very few libraries which are installed basically everywhere, hence the name manylinux. The pypa offers a special docker container and a tool called auditwheel to ensure compliance with the manylinux rules.

pyo3-pack contains a reimplementation of a major part of auditwheel automatically checking the generated library. If you want to disable those checks or build for native linux target, use the --manylinux flag.

For full manylinux compliance you need to compile in a cent os 5 docker container. The konstin2/pyo3-pack image is based on the official manylinux image. You can use it like this:

docker run --rm -v $(pwd):/io konstin2/pyo3-pack build

pyo3-pack itself is manylinux compliant when compiled for the musl target. The binaries on the release pages have additional keyring integration (through the password-storage feature), which is not manylinux compliant.

Build

FLAGS:
    -h, --help
            Prints help information

        --release
            Pass --release to cargo

        --skip-auditwheel
            [deprecated, use --manylinux instead] Don't check for manylinux compliance

        --strip
            Strip the library for minimum file size

    -V, --version
            Prints version information


OPTIONS:
    -m, --manifest-path <PATH>
            The path to the Cargo.toml [default: Cargo.toml]

        --target <TRIPLE>
            The --target option for cargo

    -b, --bindings <bindings>
            Which kind of bindings to use. Possible values are pyo3, rust-cpython, cffi and bin

        --cargo-extra-args <cargo_extra_args>...
            Extra arguments that will be passed to cargo as `cargo rustc [...] [arg1] [arg2] --`

            Use as `--cargo-extra-args="--my-arg"`
    -i, --interpreter <interpreter>...
            The python versions to build wheels for, given as the names of the interpreters. Uses autodiscovery if not
            explicitly set.
        --manylinux <manylinux>
            Whether to use and check for compliance with the manylinux1 tag (1), use it but don't check compliance (1-
            unchecked) or use the native linux tag (off)

            This option is ignored on all non-linux platforms [default: 1]  [possible values: 1, 1-unchecked, off]
    -o, --out <out>
            The directory to store the built wheels in. Defaults to a new "wheels" directory in the project's target
            directory
        --rustc-extra-args <rustc_extra_args>...
            Extra arguments that will be passed to rustc as `cargo rustc [...] -- [arg1] [arg2]`

            Use as `--rustc-extra-args="--my-arg"`

Publish

FLAGS:
        --debug
            Do not pass --release to cargo

    -h, --help
            Prints help information

        --no-strip
            Strip the library for minimum file size

        --skip-auditwheel
            [deprecated, use --manylinux instead] Don't check for manylinux compliance

    -V, --version
            Prints version information


OPTIONS:
    -m, --manifest-path <PATH>
            The path to the Cargo.toml [default: Cargo.toml]

        --target <TRIPLE>
            The --target option for cargo

    -b, --bindings <bindings>
            Which kind of bindings to use. Possible values are pyo3, rust-cpython, cffi and bin

        --cargo-extra-args <cargo_extra_args>...
            Extra arguments that will be passed to cargo as `cargo rustc [...] [arg1] [arg2] --`

            Use as `--cargo-extra-args="--my-arg"`
    -i, --interpreter <interpreter>...
            The python versions to build wheels for, given as the names of the interpreters. Uses autodiscovery if not
            explicitly set.
        --manylinux <manylinux>
            Whether to use and check for compliance with the manylinux1 tag (1), use it but don't check compliance (1-
            unchecked) or use the native linux tag (off)

            This option is ignored on all non-linux platforms [default: 1]  [possible values: 1, 1-unchecked, off]
    -o, --out <out>
            The directory to store the built wheels in. Defaults to a new "wheels" directory in the project's target
            directory
    -p, --password <password>
            Password for pypi or your custom registry. Note that you can also pass the password through
            PYO3_PACK_PASSWORD
    -r, --repository-url <registry>
            The url of registry where the wheels are uploaded to [default: https://upload.pypi.org/legacy/]

        --rustc-extra-args <rustc_extra_args>...
            Extra arguments that will be passed to rustc as `cargo rustc [...] -- [arg1] [arg2]`

            Use as `--rustc-extra-args="--my-arg"`
    -u, --username <username>
            Username for pypi or your custom registry

Develop

FLAGS:
    -h, --help
            Prints help information

        --release
            Pass --release to cargo

        --strip
            Strip the library for minimum file size

    -V, --version
            Prints version information


OPTIONS:
    -b, --bindings <binding_crate>
            Which kind of bindings to use. Possible values are pyo3, rust-cpython, cffi and bin

        --cargo-extra-args <cargo_extra_args>...
            Extra arguments that will be passed to cargo as `cargo rustc [...] [arg1] [arg2] --`

            Use as `--cargo-extra-args="--my-arg"`
    -m, --manifest-path <manifest_path>
            The path to the Cargo.toml [default: Cargo.toml]

        --rustc-extra-args <rustc_extra_args>...
            Extra arguments that will be passed to rustc as `cargo rustc [...] -- [arg1] [arg2]`

            Use as `--rustc-extra-args="--my-arg"`

Code

The main part is the pyo3-pack library, which is completely documented and should be well integratable. The accompanying main.rs takes care username and password for the pypi upload and otherwise calls into the library.

There are three different examples, which are also used for integration testing: get_fourtytwo with pyo3 bindings, points crate with cffi bindings and hello-world as a binary. The sysconfig folder contains the output of python -m sysconfig for different python versions and platform, which is helpful during development.

You need to install virtualenv and cffi (pip install virtualenv cffi) to run the tests.

You might want to have look into my blog post which explains the intricacies of building native python packages.