Ability to override the creation of the Celery App

Author: humitos

readthedocs/core/utils/__init__.py

@@ -16,7 +16,6 @@
 from future.backports.urllib.parse import urlparse
 from celery import group, chord
 
-from ..tasks import send_email_task
 from readthedocs.builds.constants import LATEST
 from readthedocs.doc_builder.constants import DOCKER_LIMITS
 
@@ -144,10 +143,13 @@ def send_email(recipient, subject, template, template_html, context=None,
         Task :py:func:`readthedocs.core.tasks.send_email_task`
             Task that handles templating and sending email message
     """
+
     if context is None:
         context = {}
     context['uri'] = '{scheme}://{host}'.format(
         scheme='https', host=settings.PRODUCTION_DOMAIN)
+
+    from ..tasks import send_email_task
     send_email_task.delay(recipient=recipient, subject=subject, template=template,
                           template_html=template_html, context=context, from_email=from_email,
                           **kwargs)

readthedocs/worker.py

@@ -1,3 +1,4 @@
+# -*- coding: utf-8 -*-
 """Celery worker application instantiation"""
 
 from __future__ import absolute_import, unicode_literals
@@ -6,14 +7,26 @@
 
 from celery import Celery
 
+from readthedocs.core.utils.extend import SettingsOverrideObject
 
-def create_application():
-    """Create a Celery application using Django settings"""
-    os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'readthedocs.settings.dev')
-    application = Celery('readthedocs')
-    application.config_from_object('django.conf:settings')
-    application.autodiscover_tasks(None)
-    return application
 
+class CeleryAppBase(object):
 
-app = create_application()  # pylint: disable=invalid-name
+    def create(self):
+        """Create a Celery application using Django settings"""
+        os.environ.setdefault(
+            'DJANGO_SETTINGS_MODULE',
+            'readthedocs.settings.dev',
+        )
+
+        application = Celery('readthedocs')
+        application.config_from_object('django.conf:settings')
+        application.autodiscover_tasks(None)
+        return application
+
+
+class CeleryApp(SettingsOverrideObject):
+    _default_class = CeleryAppBase
+
+
+app = CeleryApp().create()