cannot run appengine-admin on dev_server

Question

I've decided to try out this project:

http://code.google.com/p/appengine-admin/wiki/QuickStart

For the sake of the experiment, I took the demo guest-book shipped with app-engine. The import park look like this:

import cgi
import datetime
import wsgiref.handlers

from google.appengine.ext import db
from google.appengine.api import users
from google.appengine.ext import webapp
from google.appengine.ext.webapp.util import run_wsgi_app
from google import appengine_admin

The db model and the admin look like this

class Greeting(db.Model):

 author = db.UserProperty()
 content = db.StringProperty(multiline=True)
 date = db.DateTimeProperty(auto_now_add=True)

class AdminGreeting(appengine_admin.ModelAdmin):

 model = Greeting
 listFields = ('author','content','date')
 editFields = ('author','content','date')

appengine_admin.register(AdminGreeting)

Yet I get this exception, trying to run the site:

File "/home/<username>/python/google_appengine/google/appengine/tools/    dev_appserver.py", line 2875, in _HandleRequest
    base_env_dict=env_dict)
  File "/home/<username>/python/google_appengine/google/appengine/tools/dev_appserver.py", line 387, in Dispatch
    base_env_dict=base_env_dict)
  File "/home/<username>/python/google_appengine/google/appengine/tools/dev_appserver.py", line 2162, in Dispatch
    self._module_dict)
  File "/home/<username>/python/google_appengine/google/appengine/tools/dev_appserver.py", line 2080, in ExecuteCGI
    reset_modules = exec_script(handler_path, cgi_path, hook)
  File "/home/<username>/python/google_appengine/google/appengine/tools/dev_appserver.py", line 1976, in ExecuteOrImportScript
    exec module_code in script_module.__dict__
  File "/home/<username>/python/google_appengine/demos/guestbook/guestbook.py", line 37, in <module>
    appengine_admin.register(AdminGreeting)
  File "/home/<username>/python/google_appengine/google/appengine_admin/model_register.py", line 120, in register
    modelAdminInstance = modelAdminClass()
  File "/home/<username>/python/google_appengine/google/appengine_admin/model_register.py", line 64, in __init__
    self._extractProperties(self.listFields, self._listProperties)
  File "/home/<username>/python/google_appengine/google/appengine_admin/model_register.py", line 76, in _extractProperties
    storage.append(PropertyWrapper(getattr(self.model, propertyName), propertyName))
  File "/home/<username>/python/google_appengine/google/appengine_admin/model_register.py", line 17, in __init__
    logging.info("Caching info about property '%s'" % name)
  File "/usr/lib/python2.6/logging/__init__.py", line 1451, in info
    root.info(*((msg,)+args), **kwargs)
  File "/usr/lib/python2.6/logging/__init__.py", line 1030, in info
    self._log(INFO, msg, args, **kwargs)
  File "/usr/lib/python2.6/logging/__init__.py", line 1142, in _log
record = self.makeRecord(self.name, level, fn, lno, msg, args, exc_info, func, extra)
  File "/usr/lib/python2.6/logging/__init__.py", line 1117, in makeRecord
rv = LogRecord(name, level, fn, lno, msg, args, exc_info, func)
  File "/usr/lib/python2.6/logging/__init__.py", line 272, in __init__
from multiprocessing import current_process
  File "/home/<username>/python/google_appengine/google/appengine/tools/dev_appserver.py", line 1089, in decorate
return func(self, *args, **kwargs)
  File "/home/<username>/python/google_appengine/google/appengine/tools/dev_appserver.py", line 1736, in load_module
return self.FindAndLoadModule(submodule, fullname, search_path)
  File "/home/<username>/python/google_appengine/google/appengine/tools/dev_appserver.py", line 1089, in decorate
    return func(self, *args, **kwargs)
  File "/home/<username>/python/google_appengine/google/appengine/tools/dev_appserver.py", line 1638, in FindAndLoadModule
description)
  File "/home/<username>/python/google_appengine/google/appengine/tools/dev_appserver.py", line 1089, in decorate
return func(self, *args, **kwargs)
  File "/home/<username>/python/google_appengine/google/appengine/tools/dev_appserver.py", line 1589, in LoadModuleRestricted
description)
  File "/usr/lib/python2.6/multiprocessing/__init__.py", line 83, in <module>
    import _multiprocessing
ImportError: No module named _multiprocessing
INFO     2009-04-25 23:34:27,628 dev_appserver.py:2934] "GET / HTTP/1.1" 500 -

Any idea what could have went wrong?

Answer 1

You appear to be using Python 2.6 (given that some of the messages are from files in /usr/lib/python2.6 ...!), but Google App Engine needs Python 2.5 (any 2.5.x will do for any versions of x), so you should install and use that to run the App Engine SDK.

Answer 2

It wired that I have been using GAE with python2.6(probably 2.6.1), and every thing worked fine.

But now I get the same _multiprocess import error.(python2.6.2).

Answer 3

just do the following at the top of your something.py

import logging logging.logMultiprocessing = 0

Answer 4

import logging
logging.logMultiprocessing = 0

Worked for me

Answer 5

import logging
logging.logMultiprocessing = 0

Worked for me too. Before uploading to GAE, comment those lines.

Answer 6

Google App Engine only supports Python 2.5, and you're on a newer version.

By the look of your directories, you might be on a Linux (or is it a Mac?). On, say, Ubuntu you can "sudo apt-get install python2.5" (it won't affect your Python 2.6 at all), and then rather than:

<path-to-gae>/dev_appserver.py ...

do

python2.5 <path-to-gae>/dev_appserver.py ...

This is better than just blithely developing on 2.6 and deploying on 2.5 which is surely asking for hassles later on.

Answer 7

To make this work on my local machine (with 2.6) and on GAE, I used:

import sys, logging
if sys.version[:3] == "2.6": logging.logMultiprocessing = 0

Answer 8

As others have said, this problem occurs in Python 2.6. I used the fix proposed in this comment in the App Engine issue tracker:

A quickfix is to create a file in your app's root named `_multiprocessing.py' with 
the contents:

  import multiprocessing

This way it's possible to import the _multiprocessing module.

It worked for me using Python 2.6.2

Cheers,
Kaji