And here is why GAE loses the path (sometimes) http://code.google.com/p/googleappengine/issues/detail?id=772#c11
All, this is now an officially acknowledged bug. The cause is a "feature" which resets sys.path to a fixed default at the start of each request. Due to where we are in the QA cycle for the next push it's not going to be fixed until the push after that one, but here is a work-around. The work-around saves a copy of sys.path in a global variable when main() is called for the first time, and resets sys.path to this value on each subsequent call. Here is sample code: import sys . . (code that modifies sys.path goes here) . ultimate_sys_path = None def main(): global ultimate_sys_path if ultimate_sys_path is None: ultimate_sys_path = list(sys.path) else: sys.path[:] = ultimate_sys_path ... (rest of main goes here) ... if __name__ == '__main__': main()
