Cannot run a simple helloworld in gae (python 2.7)

Question

I am trying to run the official helloworld program in google-appengine 1.6.4 for python 2.7.

It's so frustrating to be not able to run a simple helloworld. I would appreciate any kind of help here.

Error I encounter:-

shadyabhi@MBP-archlinux ~/codes/gae $ dev_appserver.py helloworld/
INFO     2012-04-06 23:25:55,030 appengine_rpc.py:160] Server: appengine.google.com
INFO     2012-04-06 23:25:55,034 appcfg.py:582] Checking for updates to the SDK.
INFO     2012-04-06 23:25:56,709 appcfg.py:616] This SDK release is newer than the advertised release.
WARNING  2012-04-06 23:25:56,710 datastore_file_stub.py:513] Could not read datastore data from /tmp/dev_appserver.datastore
INFO     2012-04-06 23:25:56,773 dev_appserver_multiprocess.py:647] Running application dev~helloworld on port 8080: http://localhost:8080
INFO     2012-04-06 23:25:56,774 dev_appserver_multiprocess.py:649] Admin console is available at: http://localhost:8080/_ah/admin
WARNING  2012-04-06 23:26:00,928 py_zipimport.py:139] Can't open zipfile /usr/lib/python2.7/site-packages/setuptools-0.6c11.egg-info: IOError: [Errno 13] file not accessible: '/usr/lib/python2.7/site-packages/setuptools-0.6c11.egg-info'
ERROR    2012-04-06 23:26:01,101 wsgi.py:189] 
Traceback (most recent call last):
  File "/opt/google-appengine-python/google/appengine/runtime/wsgi.py", line 187, in Handle
    handler = _config_handle.add_wsgi_middleware(self._LoadHandler())
  File "/opt/google-appengine-python/google/appengine/runtime/wsgi.py", line 239, in _LoadHandler
    raise ImportError('%s has no attribute %s' % (handler, name))
ImportError: <module 'helloworld' from '/home/shadyabhi/codes/gae/helloworld/helloworld.pyc'> has no attribute app
INFO     2012-04-06 23:26:01,110 dev_appserver.py:2884] "GET / HTTP/1.1" 500 -
ERROR    2012-04-06 23:26:01,479 wsgi.py:189] 
Traceback (most recent call last):
  File "/opt/google-appengine-python/google/appengine/runtime/wsgi.py", line 187, in Handle
    handler = _config_handle.add_wsgi_middleware(self._LoadHandler())
  File "/opt/google-appengine-python/google/appengine/runtime/wsgi.py", line 239, in _LoadHandler
    raise ImportError('%s has no attribute %s' % (handler, name))
ImportError: <module 'helloworld' from '/home/shadyabhi/codes/gae/helloworld/helloworld.pyc'> has no attribute app
INFO     2012-04-06 23:26:01,486 dev_appserver.py:2884] "GET /favicon.ico HTTP/1.1" 500 -

Answer 1

If you're using python2.7 libraries there's an error with the tutorial

This line is incorrect:

application = webapp2.WSGIApplication([('/', MainPage)], debug=True)

The correct line should be:

app = webapp2.WSGIApplication([('/', MainPage)], debug=True)

The WSGI handler is complaining because it is looking for an attribute called "app".