Google app engine + python (django) deployment error: Error loading MySQLdb module

Question

I am creating an app on Google App Engine. I am using Django 1.4 and Python 2.7. Everything works fine on localhost. But after deployment it is not running, I keep getting this on admin logs:

    2012-12-15 15:02:41.870

    /base/python27_runtime/python27_lib/versions/1/lib/cacerts/urlfetch_cacerts.txt missing; without this urlfetch will not be able to validate SSL certificates.

    W 2012-12-15 15:02:41.870

    No ssl package found. urlfetch will not be able to validate SSL certificates.

    E 2012-12-15 15:02:46.086

    Traceback (most recent call last):
      File "/base/python27_runtime/python27_lib/versions/1/google/appengine/runtime/wsgi.py", line 196, in Handle
        handler = _config_handle.add_wsgi_middleware(self._LoadHandler())
      File "/base/python27_runtime/python27_lib/versions/1/google/appengine/runtime/wsgi.py", line 266, in _LoadHandler
        __import__(cumulative_path)
      File "/base/data/home/apps/s~cloudwallforever/1.363864476397206865/djangoappengine/main/__init__.py", line 28, in <module>
        setup_env()
      File "/base/data/home/apps/s~cloudwallforever/1.363864476397206865/djangoappengine/boot.py", line 82, in setup_env
        setup_logging()
      File "/base/data/home/apps/s~cloudwallforever/1.363864476397206865/djangoappengine/boot.py", line 130, in setup_logging
        if not settings.DEBUG:
      File "/base/data/home/apps/s~cloudwallforever/1.363864476397206865/django/utils/functional.py", line 276, in __getattr__
        self._setup()
      File "/base/data/home/apps/s~cloudwallforever/1.363864476397206865/django/conf/__init__.py", line 42, in _setup
        self._wrapped = Settings(settings_module)
      File "/base/data/home/apps/s~cloudwallforever/1.363864476397206865/django/conf/__init__.py", line 87, in __init__
        mod = importlib.import_module(self.SETTINGS_MODULE)
      File "/base/data/home/apps/s~cloudwallforever/1.363864476397206865/django/utils/importlib.py", line 35, in import_module
        __import__(name)
      File "/base/data/home/apps/s~cloudwallforever/1.363864476397206865/settings.py", line 6, in <module>
        import django.db.backends.mysql.base
      File "/base/data/home/apps/s~cloudwallforever/1.363864476397206865/django/db/backends/mysql/base.py", line 14, in <module>
        raise ImproperlyConfigured("Error loading MySQLdb module: %s" % e)
    ImproperlyConfigured: Error loading MySQLdb module: No module named MySQLdb

Any ideas why it is happening?

Answer 1

The 'Django Support' documentation hints at the solution, but doesn't make it explicit:

Since the standard django.db.backends.mysql backend uses MySQLdb internally, app.yaml must reference MySQLdb in the list of libraries.

Adding the following to app.yaml seems to fix the ImportError:

libraries:
- name: MySQLdb
  version: "latest"

Note that MySQLdb is not currently included in the list of available third party libraries. I tried it on a whim and it seems to have fixed the issue for me, YMMV.enter link description here

Answer 2

As the Cloud SQL docs clearly state, you should be using ''google.appengine.ext.django.backends.rdbms' as your database engine setting.