Pass rpc connection to pre_start_hook.

The pre_start_hook allows a manager to perform some additional service
setup before the service starts reading messages from message queues.
This patch moves the hook just a bit so that it's after creating the rpc
connection, but before creating the default queues, and most importantly
still before the service starts reading from the queues.

The pre_start_hook now gets the rpc_connection as an argument.  That
will allow this hook to set up some additional queues beyond the ones
that are set up by default in the base service code.

Change-Id: I5bf7795fca21627566ef4f688d45dc83bb953d1b

nova/compute/manager.py

@@ -407,7 +407,7 @@ class ComputeManager(manager.SchedulerDependentManager):
         self._report_driver_status(context)
         self.publish_service_capabilities(context)
 
-    def pre_start_hook(self):
+    def pre_start_hook(self, **kwargs):
         """After the service is initialized, but before we fully bring
         the service up by listening on RPC queues, make sure to update
         our available resources.

nova/manager.py

@@ -189,7 +189,7 @@ class Manager(base.Base):
         """
         pass
 
-    def pre_start_hook(self):
+    def pre_start_hook(self, **kwargs):
         """Hook to provide the manager the ability to do additional
         start-up work before any RPC queues/consumers are created. This is
         called after other initialization has succeeded and a service

nova/service.py

@@ -400,8 +400,6 @@ class Service(object):
         except exception.NotFound:
             self._create_service_ref(ctxt)
 
-        self.manager.pre_start_hook()
-
         if self.backdoor_port is not None:
             self.manager.backdoor_port = self.backdoor_port
 
@@ -409,6 +407,8 @@ class Service(object):
         LOG.debug(_("Creating Consumer connection for Service %s") %
                   self.topic)
 
+        self.manager.pre_start_hook(rpc_connection=self.conn)
+
         rpc_dispatcher = self.manager.create_rpc_dispatcher()
 
         # Share this same connection for these Consumers

nova/tests/test_service.py

@@ -159,7 +159,7 @@ class ServiceTestCase(test.TestCase):
         self._service_start_mocks()
         # pre_start_hook is called after service record is created,
         # but before RPC consumer is created
-        self.manager_mock.pre_start_hook()
+        self.manager_mock.pre_start_hook(rpc_connection=mox.IgnoreArg())
         self.manager_mock.create_rpc_dispatcher()
         # post_start_hook is called after RPC consumer is created.
         self.manager_mock.post_start_hook()