Updates for automatic triggering of policies

* Switch policy router queue to not be "tower" so that we don't
  fall into a chicken/egg scenario
* Show fixed policy list in serializer so a user can determine if
  an instance is manually managed
* Change IG membership mixin to not directly handle applying topology
  changes. Instead it just makes sure the policy instance list is
  accurate
* Add create/delete hooks for instances and groups to trigger policy
  re-evaluation
* Update policy algorithm for fairer distribution
* Fix an issue where CELERY_ROUTES wasn't renamed after celery/django
  upgrade
* Update unit tests to be more explicit
* Update count calculations used by algorithm to only consider
  non-manual instances
* Adding unit tests and fixture
* Don't propagate logging messages from awx.main.tasks and
  awx.main.scheduler
* Use advisory lock to prevent policy eval conflicts
* Allow updating instance groups from view

awx/main/models/ha.py

@@ -2,7 +2,7 @@
 # All Rights Reserved.
 
 from django.db import models
-from django.db.models.signals import post_save
+from django.db.models.signals import post_save, post_delete
 from django.dispatch import receiver
 from django.utils.translation import ugettext_lazy as _
 from django.conf import settings
@@ -136,6 +136,32 @@ class JobOrigin(models.Model):
         app_label = 'main'
 
 
+@receiver(post_save, sender=InstanceGroup)
+def on_instance_group_saved(sender, instance, created=False, raw=False, **kwargs):
+    if created:
+        from awx.main.tasks import apply_cluster_membership_policies
+        apply_cluster_membership_policies.apply_async(countdown=5)
+
+
+@receiver(post_save, sender=Instance)
+def on_instance_saved(sender, instance, created=False, raw=False, **kwargs):
+    if created:
+        from awx.main.tasks import apply_cluster_membership_policies
+        apply_cluster_membership_policies.apply_async(countdown=5)
+
+
+@receiver(post_delete, sender=InstanceGroup)
+def on_instance_group_deleted(sender, instance, using, **kwargs):
+    from awx.main.tasks import apply_cluster_membership_policies
+    apply_cluster_membership_policies.apply_async(countdown=5)
+
+
+@receiver(post_delete, sender=Instance)
+def on_instance_deleted(sender, instance, using, **kwargs):
+    from awx.main.tasks import apply_cluster_membership_policies
+    apply_cluster_membership_policies.apply_async(countdown=5)
+
+
 # Unfortunately, the signal can't just be connected against UnifiedJob; it
 # turns out that creating a model's subclass doesn't fire the signal for the
 # superclass model.