How to force a python wheel to be platform specific when building it?

I am working on a python2 package in which the setup.py contains some custom install commands. These commands actually build some Rust code and output some .dylib files that are moved into the python package.

An important point is that the Rust code is outside the python package.

setuptools is supposed to detect automatically if the python package is pure python or platform specific (if it contains some C extensions for instance).
In my case, when I run python setup.py bdist_wheel, the generated wheel is tagged as a pure python wheel: <package_name>-<version>-py2-none-any.whl.
This is problematic because I need to run this code on different platforms, and thus I need to generated one wheel per platform.

Is there a way, when building a wheel, to force the build to be platform specific ?

Answers:

Thank you for visiting the Q&A section on Magenaut. Please note that all the answers may not help you solve the issue immediately. So please treat them as advisements. If you found the post helpful (or not), leave a comment & I’ll get back to you as soon as possible.

Method 1

Here’s the code that I usually look at from uwsgi

The basic approach is:

setup.py

# ...

try:
    from wheel.bdist_wheel import bdist_wheel as _bdist_wheel
    class bdist_wheel(_bdist_wheel):
        def finalize_options(self):
            _bdist_wheel.finalize_options(self)
            self.root_is_pure = False
except ImportError:
    bdist_wheel = None

setup(
    # ...
    cmdclass={'bdist_wheel': bdist_wheel},
)

The root_is_pure bit tells the wheel machinery to build a non-purelib (pyX-none-any) wheel. You can also get fancier by saying there are binary platform-specific components but no cpython abi specific components.

Method 2

The modules setuptools, distutils and wheel decide whether a python distribution is pure by checking if it has ext_modules.

If you build an external module on your own, you can still list it in ext_modules so that the building tools know it exists. The trick is to provide an empty list of sources so that setuptools and distutils will not try to build it. For example,

setup(
    ...,
    ext_modules=[
        setuptools.Extension(
            name='your.external.module',
            sources=[]
        )
    ]
)

This solution worked better for me than patching the bdist_wheel command. The reason is that bdist_wheel calls the install command internally and that command checks again for the existence of ext_modules to decide between purelib or platlib install. If you don’t list the external module, you end up with the lib installed in a purelib subfolder inside the wheel. That causes problems when using auditwheel repair, which complains about the extensions being installed in a purelib folder.

Method 3

You can also specify/spoof a specific platform name when building wheels by specifying a --plat-name:

python setup.py bdist_wheel --plat-name=manylinux1_x86_64

Method 4

Neither the root_is_pure trick nor the empty ext_modules trick worked for me, but after MUCH searching myself, I finally found a working solution in ‘pip setup.py bdist_wheel’ no longer builds forced non-pure wheels

Basically, you override the ‘has_ext_modules’ function in the Distribution class, and set distclass to point to the overriding class. At that point, setup.py will believe you have a binary distribution, and will create a wheel with the specific version of python, the ABI, and the current architecture. As suggested by https://stackoverflow.com/users/5316090/py-j:

from setuptools import setup
from setuptools.dist import Distribution

DISTNAME = "packagename"
DESCRIPTION = ""
MAINTAINER = ""
MAINTAINER_EMAIL = ""
URL = ""
LICENSE = ""
DOWNLOAD_URL = ""
VERSION = '1.2'
PYTHON_VERSION = (2, 7)


# Tested with wheel v0.29.0
class BinaryDistribution(Distribution):
    """Distribution which always forces a binary package with platform name"""
    def has_ext_modules(foo):
        return True


setup(name=DISTNAME,
      description=DESCRIPTION,
      maintainer=MAINTAINER,
      maintainer_email=MAINTAINER_EMAIL,
      url=URL,
      license=LICENSE,
      download_url=DOWNLOAD_URL,
      version=VERSION,
      packages=["packagename"],

      # Include pre-compiled extension
      package_data={"packagename": ["_precompiled_extension.pyd"]},
      distclass=BinaryDistribution)

Method 5

I find Anthony Sottile’s answer great, but didn’t work for me.

My case is that I have to enforce the wheel to be created for x86_64, but any python3, so making root impure actually caused my wheel to be py36-cp36 🙁

A better way, IMO, in general is just to use sys.argv:

from setuptools import setup
import sys

sys.argv.extend(['--plat-name', 'x86_64'])
setup(name='example-wheel')

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0