Clarify the init logic for the ML2 plugin

This patch cleans up the init logic for the plugin so that
we better separate the tasks required for establishing
the integration with DHCP and RPC layers.

In other words: some bikeshedding whilst dealing with bug #1444112

Change-Id: I68710ad002b0e1b5bff40baa5de343b0bd7ecea6

diff --git a/neutron/plugins/ml2/plugin.py b/neutron/plugins/ml2/plugin.py
index 6656a88d2907209c10d17c27d7ccbf5fbd5cffd3..c57bfe71d62de5cd0109e70f59f08a6df92b9ac6 100644 (file)
--- a/neutron/plugins/ml2/plugin.py
+++ b/neutron/plugins/ml2/plugin.py
@@ -141,32 +141,36 @@ class Ml2Plugin(db_base_plugin_v2.NeutronDbPluginV2,
         self.mechanism_manager.initialize()
 
         self._setup_rpc()
-
-        # REVISIT(rkukura): Use stevedore for these?
-        self.network_scheduler = importutils.import_object(
-            cfg.CONF.network_scheduler_driver
-        )
-
-        self.start_periodic_dhcp_agent_status_check()
+        self._setup_dhcp()
         LOG.info(_LI("Modular L2 Plugin initialization complete"))
 
     def _setup_rpc(self):
+        """Initialize components to support agent communication."""
         self.notifier = rpc.AgentNotifierApi(topics.AGENT)
         self.agent_notifiers[const.AGENT_TYPE_DHCP] = (
             dhcp_rpc_agent_api.DhcpAgentNotifyAPI()
         )
+        self.endpoints = [
+            rpc.RpcCallbacks(self.notifier, self.type_manager),
+            securitygroups_rpc.SecurityGroupServerRpcCallback(),
+            dvr_rpc.DVRServerRpcCallback(),
+            dhcp_rpc.DhcpRpcCallback(),
+            agents_db.AgentExtRpcCallback(),
+            metadata_rpc.MetadataRpcCallback()
+        ]
+
+    def _setup_dhcp(self):
+        """Initialize components to support DHCP."""
+        self.network_scheduler = importutils.import_object(
+            cfg.CONF.network_scheduler_driver
+        )
+        self.start_periodic_dhcp_agent_status_check()
 
     def start_rpc_listeners(self):
-        self.endpoints = [rpc.RpcCallbacks(self.notifier, self.type_manager),
-                          securitygroups_rpc.SecurityGroupServerRpcCallback(),
-                          dvr_rpc.DVRServerRpcCallback(),
-                          dhcp_rpc.DhcpRpcCallback(),
-                          agents_db.AgentExtRpcCallback(),
-                          metadata_rpc.MetadataRpcCallback()]
+        """Start the RPC loop to let the plugin communicate with agents."""
         self.topic = topics.PLUGIN
         self.conn = n_rpc.create_connection(new=True)
-        self.conn.create_consumer(self.topic, self.endpoints,
-                                  fanout=False)
+        self.conn.create_consumer(self.topic, self.endpoints, fanout=False)
         return self.conn.consume_in_threads()
 
     def _filter_nets_provider(self, context, networks, filters):