environment.py

# -*- coding: utf-8 -*- 
"""Add current directory to Python's site-packages path.
"""
import os
import site
import sys

ROOT = os.path.dirname(os.path.abspath(__file__))
path = lambda *a: os.path.join(ROOT, *a)

prev_sys_path = list(sys.path)

site.addsitedir(path('lib'))
site.addsitedir(path('handlers'))
if os.path.exists(path('vendor')):
    for directory in os.listdir(path('vendor')):
        full_path = path('vendor/%s' % directory)
        if os.path.isdir(full_path):
            site.addsitedir(full_path)

# Move the new items to the front of sys.path. (via virtualenv)
new_sys_path = []
for item in list(sys.path):
    if item not in prev_sys_path:
        new_sys_path.append(item)
        sys.path.remove(item)
sys.path[:0] = new_sys_path