Merge pull request #297 from mjjohnson/ticket_17069

   through the filter. Handling of that record will not proceed if the callback

   returns False.

   For instance, to filter out :class:`~django.http.UnreadablePostError`

   (raised when a user cancels an upload) from the admin emails, you would

   create a filter function::

    from django.http import UnreadablePostError

    def skip_unreadable_post(record):

        if record.exc_info:

            exc_type, exc_value = record.exc_info[:2]

            if isinstance(exc_value, UnreadablePostError):

                return False

        return True

   and then add it to your logging config::

        'filters': {

            'skip_unreadable_posts': {

                '()': 'django.utils.log.CallbackFilter',

                'callback': skip_unreadable_post,

            }

        },

        'handlers': {

            'mail_admins': {

                'level': 'ERROR',

                'filters': ['skip_unreadable_posts'],

                'class': 'django.utils.log.AdminEmailHandler'

            }

        },

.. class:: RequireDebugFalse()

   .. versionadded:: 1.4