bootstrap.py

#!/usr/bin/env python
import os
import sys
import subprocess
import shutil

pwd = os.path.abspath(os.path.dirname(__file__))
vedir = os.path.join(pwd,"ve")

if os.path.exists(vedir):
    shutil.rmtree(vedir)

os.environ['PIP_DOWNLOAD_CACHE'] = os.path.expanduser(os.path.join('~','.cache','pip'))
pip = os.path.join(pwd,"pip.py")
requirements = os.path.join(pwd,"requirements.txt")
print pip,requirements
subprocess.call([pip,"install",
                 "-E",vedir,
                 "--enable-site-packages",
                 "--requirement",requirements])