Django 1.9 Custom Logging Handler Class: “Unable to configure handler 'mail_admins': Apps aren't loaded yet.”

Question

I'm in the process of upgrading an existing Django application from 1.8 to 1.9 (1.9.4, specifically). I use a custom logging handler to send admin error emails through a third-party email provider (SendGrid).

When executing the runserver command, the following traceback is generated:

Traceback (most recent call last):
  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/Users/coredev/.virtualenvs/django19/lib/python3.4/site-packages/django/core/management/__init__.py", line 353, in execute_from_command_line
    utility.execute()
  File "/Users/coredev/.virtualenvs/django19/lib/python3.4/site-packages/django/core/management/__init__.py", line 327, in execute
    django.setup()
  File "/Users/coredev/.virtualenvs/django19/lib/python3.4/site-packages/django/__init__.py", line 17, in setup
    configure_logging(settings.LOGGING_CONFIG, settings.LOGGING)
  File "/Users/coredev/.virtualenvs/django19/lib/python3.4/site-packages/django/utils/log.py", line 71, in configure_logging
    logging_config_func(logging_settings)
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/logging/config.py", line 789, in dictConfig
    dictConfigClass(config).configure()
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/logging/config.py", line 565, in configure
    '%r: %s' % (name, e))
ValueError: Unable to configure handler 'mail_admins': Apps aren't loaded yet.

Here are the relevant code snippets for the custom logging class:

Custom handler in settings.LOGGING:

'mail_admins': {
    'level': 'ERROR',
    'class': 'coredev.utils.logging.SendgridAdminEmailHandler',
    'filters': ['require_debug_false'],
    'include_html': True,
}

coredev/utils/logging.py

from django.utils.log import AdminEmailHandler
from coredev.tasks import sendgrid_email
from settings import ADMINS

class SendgridAdminEmailHandler(AdminEmailHandler):

    def send_mail(self, subject, message, *args, **kwargs):

        for admin in ADMINS:
            try:
                if kwargs.get('html_message') is not None:
                    message_content = kwargs['html_message']
                else:
                    message_content = message

                sendgrid_email(admin[1], subject, message_content, message)
            except:
                pass

coredev/tasks.py (relevant snippet)

import sendgrid
from django.conf import settings

def sendgrid_email(to, subject, body, alt_body, from_email = settings.DEFAULT_FROM_EMAIL, template_id = settings.DEFAULT_TEMPLATE_ID):

    sg = sendgrid.SendGridClient(settings.EMAIL_HOST_USER, settings.EMAIL_HOST_PASSWORD, raise_errors = True)
    message = sendgrid.Mail()

    message.add_filter('templates', 'enable', '1')
    message.add_filter('templates', 'template_id', template_id)

    message.add_to(to)
    message.set_from(from_email)
    message.set_subject(subject)
    message.set_html(body)
    if alt_body:
        message.set_text(alt_body)

    sg.send(message)

I've looked through the Django documentation ( https://docs.djangoproject.com/en/1.9/topics/logging/ ), as well as StackOverflow and Google, but I've been unable to find a solution as of yet. I understand that models are not to be imported until all apps are "ready", but I don't believe that I am importing any models in this code, so I'm not sure why this error is occurring.

What part of my code is causing this issue? What steps do I need to take to make my custom logging handler compatible with Django 1.9's AppRegistry; specifically, so that I no longer get the "Apps aren't loaded yet" error?

Answer 1

I had a similar problem. I was able to resolve it by importing the settings before importing anything else. Also, take @Alasdair's advice.

from django.conf import settings
from django.utils.log import AdminEmailHandler
from coredev.tasks import sendgrid_email

class SendgridAdminEmailHandler(AdminEmailHandler):
    def send_mail(self, subject, message, *args, **kwargs):
        for admin in settings.ADMINS:
            try:
                if kwargs.get('html_message') is not None:
                    message_content = kwargs['html_message']
                else:
                    message_content = message
                sendgrid_email(admin[1], subject, message_content, message)
            except:
                pass