Using Werkzeug's debugger on GAE dev server

There is a very good web framework called Werkzeug. The debugger of Werkzeug is pretty nice and we can use inline console on our web browser with it.

The author of Werkzeug wrote an article of how to use this debugger with GAE dev server. However according this article, the inline console is not usable.

After a little struggling, finally I can use the debugger on GAE dev server. GAE dev server creates an instance of DebuggedApplication on every request. I think its the reason why. So, it seems that specifying the instance as the module global singleton made it work.

_debugged_app = None
app = ... build your wsgi app ...

def main():
  # Only run the debugger in development.
  import os, sys
  if 'SERVER_SOFTWARE' in os.environ and os.environ['SERVER_SOFTWARE'].startswith('Dev'):
    # use our debug.utils with Jinja2 templates
    import debug.utils
    sys.modules['werkzeug.debug.utils'] = debug.utils

    # don't use inspect.getsourcefile because the imp module is empty 
    import inspect
    inspect.getsourcefile = inspect.getfile
    
    # wrap the application
    from werkzeug import DebuggedApplication
    global _debugged_app
    if _debugged_app is None:
      _debugged_app = app = DebuggedApplication(app, evalex=True)
    else:
      app = _debugged_app