Python Packaging

Compile Python extensions on Windows

  • Install Windows SDK

  • Run “Windows SDK Command Prompt”

  • Type:

    setenv /x64 /release
    set MSSDK=1
    set DISTUTILS_USE_SDK=1
    

See also Windows.

Build a Python Wheel package on Windows

For Python 2.7, you need: Download Visual C++ Compiler for Python 2.7.

Steps:

  • Install pip

  • Install wheel using pip:

    \python27\python.exe -m pip install wheel
    
  • Run “Windows SDK Command Prompt”

  • Setup the environment to build code in 64-bit mode (replace /x64 with /x86 for 32bit):

    setenv /x64 /release
    set MSSDK=1
    set DISTUTILS_USE_SDK=1
    
  • Go to your project

  • Cleanup the project (is it really needed?):

    del build\*
    del dist\*
    
  • Build the wheel and upload it:

    \python27\python.exe setup.py bdist_wheel upload
    

Notes:

  • To build a 32-bit wheel, you need 32-bit Python and configure the SDK using /x86.
  • Python 2.7 requires the Windows SDK v7.0 because Python 2.7 is built using Visual Studio 2008 (MSVCR90). Python 3.3 is built using Visual Studio 2010.
  • It looks like Python 3.3 doesn’t need MSSDK and DISTUTILS_USE_SDK environment variables anymore.

See also Windows.

Python environment markers

https://wiki.openstack.org/wiki/Python3#Environment_markers

pip supports environment markers in requirements since pip 6.0, example of requirement:

six
futures; python_version < '3.2'

pip uses “;” (colon) separator but requires “; ” (colon, space) if the requirement uses an URL. A space is added for readability (spaces are ignored).

Environment markers in extra requirements of setup.cfg:

[extras]
test =
    six
    futures :python_version < '3.2'

The separator is the “:” (colon), space is only used for readability (spaces are ignored).

Environment markers in extra requirements of setup.py:

expected_requirements = {
    "test:python_version < '3.2'": ['futures'],
    "test": ['six']
}

pip issues

  • Upgrading pip3 replaces /usr/bin/pip with the Python 3 pip
  • Once, I got two dist-info directories for pip (ls /usr/lib*/python3.4/site-packages/pip-*.dist-info -d) which broke python3 -m venv: ensurepip was unable to find the system pip and Fedora doesn’t include bundled wheel packages of ensurepip in the python3-libs package
  • With pip 7.0 and newer, pip3 install Routes; pip2 install Routes installs the Python 3 version of Routes on Python 2. pip3 creates a wheel package using 2to3 but Routes 2.1 announces universal wheel support which is wrong.
  • Wheel caching doesn’t work on pip 7.0, 7.0.1 and 7.0.2. It was fixed in pip 7.0.3.