Update the wheels that are used to install pip and setuptools in each newly-created virtualenv

venv_support_update.py

#!/usr/bin/env python3.4

import re
import sys
import os.path
import logging
import subprocess
from pathlib import Path

from six import text_type


log = logging.getLogger('venv_support_update')


# Will be passed to each invocation of 'pip'.  (If you need e.g. '--trusted-host ...', this is the place for it.)
PIP_ARGS = []


def main():
    # For pyenv/pyenv-virtualenvwrapper installations.
    for path in Path(os.path.expanduser('~/.pyenv/versions')).iterdir():
        if re.match(r'^\d+(\.\d+)+$', path.name):
            log.debug('{}...'.format(path.name))
            version_info = tuple(int(x) for x in path.name.split('.'))
            pip_path = path / 'bin/pip'
            venv_support_path = path / 'lib/python{}.{}/site-packages/virtualenv_support'.format(*version_info[:2])
            update_virtualenv_support(pip_path, venv_support_path)

    # For user-level installations of virtualenv without pyenv.
    for path in Path(os.path.expanduser('~/.local/lib')).iterdir():
        m = re.match(r'^python(\d+)\.(\d+)$', path.name)
        if m:
            pip_path = '/usr/local/bin/pip{}.{}'.format(m.group(1), m.group(2))  # XXX: This is probably not true in every environment.
            update_virtualenv_support(pip_path, path / 'site-packages/virtualenv_support')


def update_virtualenv_support(pip_path, venv_support_path):
    if not venv_support_path.exists():
        print('WARNING: No virtualenv_support directory: {}'.format(venv_support_path), file=sys.stderr)
        return

    cmd = [text_type(pip_path)] + list(PIP_ARGS) + ['install', '-d', '.']
    log.debug(' - Checking setuptools...')
    subprocess.check_call(cmd + ['setuptools'], cwd=text_type(venv_support_path))
    log.debug(' - Checking pip...')
    subprocess.check_call(cmd + ['pip'], cwd=text_type(venv_support_path))

    # TODO: Check if we upgraded anything.  (You'll see a "file already downloaded" message if not.)

    # TODO: Clean up old versions (though it seems that the most-recent one is automatically used;
    # small miracles, right?).


if __name__ == '__main__':
    logging.basicConfig(level=logging.DEBUG)
    main()