pybuild-header-dependency

pybuild-header-dependency

pybuild-header-dependency is a helper package to resolve C/C++ header-only libraries for Python build with native extensions.

Why this project?

Are you developing a Python project with C/C++ extensions? You are likely to have some dependencies on C/C++ libraries. Managing C/C++ dependencies can be tricky in this case because setuptools, the standard build system for Python extension module, does not have a proper package management for C/C++ libraries.

In many cases, your C/C++ dependencies are header-only libraries. You need to then tell setuptools the path to the needed header files. Some header-only libraries, e.g. pybind11, are directly installable from PyPI and you can resolve the header location by calling the function get_include. This is however not universally applicable for all header-only libraries.

This project is a helper package aiming to facilitate the build process by automatically downloading the needed C/C++ header-only libraries and providing a include path to the build system (setuptools).

Alternatives to this project

pybind11 also provides a way to build C/C++ extensions using full cmake build system. In this way, all the C/C++ dependencies can be resolved in cmake. Please refer to their documentation. This project, however, aims at the developers using setuptools to build the extensions.

Installation

You rarely need to install it manually. If you do, you can directly install it from PyPI:

pip install pybuild-header-dependency

Usage

The usage below is under the assumption that you develop your project according to PEP518 with pyproject.toml.

Build dependency

Specify pybuild-header-dependency as a build dependency in your pyproject.toml. It should include something like below:

[build-system]
requires = [
    "setuptools",
    "wheel",
    "pybuild-header-dependency"
    # your other Python build dependencies
]
build-backend = "setuptools.build_meta"

Get headers

To resolve your needed headers in build time, call pybuild-header-dependency in your setup.py. See below for some clues:

from setuptools import Extension
from setuptools import setup
from pybuild_header_dependency import HeaderResolver

# resolve your C/C++ header-only dependencies
resolver = HeaderResolver({
    "eigen": None,  # None as latest version
    "boost": "1.78"  # pinned version
})

# define an extension module
ext = Extension(
    include_dirs=[str(resolver.get_include())],
    # your other extension configurations
)

# begin build
setup(
    ext_modules=[ext],
    # your other package configurations
)

You can look at pkg.json for supported header-only libraries.

Build

Once you configure your project as above, you should be able to build it without any C/C++ packages or packages managers installed.

pip wheel -w dist --no-deps .

The build process will download the necessary header files automatically.

Limitation

As the name of this project suggests, this project supports header-only C/C++ libraries. If you project depends on some static/dynamic libraries, you need to use a full build system like cmake.

The default way of downloading packages from GitLab/GitHub is based on releases. You can of course make a custom downloader.

License

This project is licensed under the BSD-3-Clause license, see LICENSE for details.

Licenses of the libraries

Each supported head-only library is licensed under its own terms. Please consult them individually.

Contribution

You are more than welcome to make contributions to this project. Please have a look at the pkg.json for some examples about how to add new packages. Also refer to boost.py for an example of custom downloader.