prebuilt-binaries 0.4.0

A setuptools command for packaging pre-built binary python extension modules.

A setuptools command for packaging pre-built binary python extension modules.

If you are already using cmake as your build tool, having to then build your library with setuptools in order to package it can be annoying.

prebuild_binaries allows you to pass an already built extension module (.pyd file) to setuptools for inclusion in a wheel.

Note that it is your responsibility to do this with the same python version as the file was created with - however this is pretty easy to get right when it’s part of the same build chain.

API

class PrebuiltExtension (input_filename, package=None)

input_filename is the full path to the pre-built extension module (.pyd file) The stem of input_filename is used for the name of the extension module.

If package is passed then the name of the extension module will be <package>.<name>

class prebuilt_binary

setuptools command class that takes PrebuiltExtension instances as parameters and copies the input file to the correct location. It is a replacement for the setuptools build_ext command.

Minimal setup.py example

import os
from setuptools import setup
from prebuilt_binaries import prebuilt_binary, PrebuiltExtension

ext_module = PrebuiltExtension(os.environ['PREBUILT_FILE'])

setup(
    name='my_package',
    version='version',
    cmdclass={
        'build_ext': prebuilt_binary,
    },
    ext_modules=[ext_module]
)

In this example the PREBUILT_FILE environment variable contains the desired path. The cmdclass mapping is required to tell setuptools to use the prebuilt_binary class to “build” the extensions specified in ext_modules.

CMakeLists.txt example

find_package(Python REQUIRED)

file(GLOB build_wheel_SOURCE_FILES pyproject.toml setup.py)

add_custom_target(build_wheel
    COMMAND ${CMAKE_COMMAND} -E env PREBUILT_FILE=$<TARGET_FILE:py_module> ${Python_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/setup.py bdist_wheel
    SOURCES ${build_wheel_SOURCE_FILES}
    )

add_dependencies(build_wheel py_module)

In this example cmake file py_module is the name of the target that builds the extension module. It sets the PREBUILT_FILE environment variable used by setup.py to the output file of the py_module target.

Build dependencies

Don’t forget to set prebuilt_binaries as a build-time dependancy in your pyproject.toml file:

[build-system]
requires = ["setuptools", "prebuilt_binaries"]

or in your setup.cfg file:

[options]
setup_requires =
    setuptools
    prebuilt_binaries