distutils: How to pass a user defined parameter to setup.py?

Question

Please prompt me how to pass a user-defined parameter both from the command line and setup.cfg configuration file to distutils\' setup.py script. I want to write a setup.py

Answer 1

Yes, it's 2015 and the documentation for adding commands and options in both setuptools and distutils is still largely missing.

After a few frustrating hours I figured out the following code for adding a custom option to the install command of setup.py:

from setuptools.command.install import install


class InstallCommand(install):
    user_options = install.user_options + [
        ('custom_option=', None, 'Path to something')
    ]

    def initialize_options(self):
        install.initialize_options(self)
        self.custom_option = None

    def finalize_options(self):
        #print('The custom option for install is ', self.custom_option)
        install.finalize_options(self)

    def run(self):
        global my_custom_option
        my_custom_option = self.custom_option
        install.run(self)  # OR: install.do_egg_install(self)

It's worth to mention that install.run() checks if it's called "natively" or had been patched:

if not self._called_from_setup(inspect.currentframe()):
    orig.install.run(self)
else:
    self.do_egg_install()

At this point you register your command with setup:

setup(
    cmdclass={
        'install': InstallCommand,
    },
    :