Fix copy API

In web/task split deployment web and task container no longer share the same redis cache

In the original code we use redis cache to pass the list of sub objects that need to be copied to the new object

In this PR we extracted out the logic that computes the sub_object_list and move it into deep_copy_model_obj task

awx/api/generics.py

@@ -5,13 +5,11 @@
 import inspect
 import logging
 import time
-import uuid
 
 # Django
 from django.conf import settings
 from django.contrib.auth import views as auth_views
 from django.contrib.contenttypes.models import ContentType
-from django.core.cache import cache
 from django.core.exceptions import FieldDoesNotExist
 from django.db import connection, transaction
 from django.db.models.fields.related import OneToOneRel
@@ -967,16 +965,11 @@ class CopyAPIView(GenericAPIView):
         if hasattr(new_obj, 'admin_role') and request.user not in new_obj.admin_role.members.all():
             new_obj.admin_role.members.add(request.user)
         if sub_objs:
-            # store the copied object dict into cache, because it's
-            # often too large for postgres' notification bus
-            # (which has a default maximum message size of 8k)
-            key = 'deep-copy-{}'.format(str(uuid.uuid4()))
-            cache.set(key, sub_objs, timeout=3600)
             permission_check_func = None
             if hasattr(type(self), 'deep_copy_permission_check_func'):
                 permission_check_func = (type(self).__module__, type(self).__name__, 'deep_copy_permission_check_func')
             trigger_delayed_deep_copy(
-                self.model.__module__, self.model.__name__, obj.pk, new_obj.pk, request.user.pk, key, permission_check_func=permission_check_func
+                self.model.__module__, self.model.__name__, obj.pk, new_obj.pk, request.user.pk, permission_check_func=permission_check_func
             )
         serializer = self._get_copy_return_serializer(new_obj)
         headers = {'Location': new_obj.get_absolute_url(request=request)}