virtualenv installer using builtin modules (python 2.7), also installs pip and wheel

virtualenv_installer.py

from hashlib import sha256

import os
import sys
import logging
import urllib2
import tempfile

# extracted from https://pypi.org/simple/virtualenv/
VIRTUALENV_URL = 'https://files.pythonhosted.org/packages/33/5d/' \
                 '314c760d4204f64e4a968275182b7751bd5c3249094757b39ba987dcfb5a/virtualenv-16.4.3-py2.py3-none-any.whl'
HASH = '6aebaf4dd2568a0094225ebbca987859e369e3e5c22dc7d52e5406d504890417'


logging.basicConfig(stream=sys.stdout, level=logging.DEBUG)

def _install_virtualenv(path):
    logging.info('Downloading virtualenv from %r ...' % VIRTUALENV_URL)
    data = urllib2.urlopen(VIRTUALENV_URL).read()
    assert sha256(data).hexdigest() == HASH, 'hash error... MITM?'

    with tempfile.NamedTemporaryFile('wb', suffix=".zip", delete=False) as zf:
        zf.write(data)
        zf.flush()

        sys.path.insert(0, zf.name)
        import virtualenv

        logging.info('Creating environment using virtualenv...')
        virtualenv.create_environment(path)
        logging.info('Done!')


def prepare_virtualenv(path):
    abspath = os.path.abspath(path)
    sys.path.insert(0, abspath)
    try:
        activator_path = os.path.join(abspath, 'Scripts', 'activate_this.py')

        if not os.path.isfile(activator_path):
            raise ImportError()

        execfile(activator_path, {'__file__': activator_path})
    except ImportError:
        logging.info('Will install virtualenv at %r since the module is not found...' % path)
        _install_virtualenv(path)
        prepare_virtualenv(path)


if __name__ == '__main__':
    prepare_virtualenv('./virtualenv_test')
    import pip
    print pip.__file__