Return no active network if the agent has not been learnt yet

Sometimes the agent message to get the active networks is
processed before the agent is learnt by Neutron. Neutron throws an
error, but it should simply return no network

Change-Id: I6da0ca578cfe1fe0885138a5e2da76278f791491
Closes-bug: #1302838

diff --git a/neutron/db/agentschedulers_db.py b/neutron/db/agentschedulers_db.py
index aa8dfadb63bbc6228648e42cbdb79dc25e97f043..2022dbe3ec79bcbb4111e86dca79aa1786ee7a88 100644 (file)
--- a/neutron/db/agentschedulers_db.py
+++ b/neutron/db/agentschedulers_db.py
@@ -23,6 +23,7 @@ from neutron.common import constants
 from neutron.common import utils
 from neutron.db import agents_db
 from neutron.db import model_base
+from neutron.extensions import agent as ext_agent
 from neutron.extensions import dhcpagentscheduler
 from neutron.openstack.common import log as logging
 
@@ -184,8 +185,13 @@ class DhcpAgentSchedulerDbMixin(dhcpagentscheduler
             return {'networks': []}
 
     def list_active_networks_on_active_dhcp_agent(self, context, host):
-        agent = self._get_agent_by_type_and_host(
-            context, constants.AGENT_TYPE_DHCP, host)
+        try:
+            agent = self._get_agent_by_type_and_host(
+                context, constants.AGENT_TYPE_DHCP, host)
+        except ext_agent.AgentNotFoundByTypeHost:
+            LOG.debug("DHCP Agent not found on host %s", host)
+            return []
+
         if not agent.admin_state_up:
             return []
         query = context.session.query(NetworkDhcpAgentBinding.network_id)

diff --git a/neutron/tests/unit/openvswitch/test_agent_scheduler.py b/neutron/tests/unit/openvswitch/test_agent_scheduler.py
index ddc1cee8b3cb7fa6b266587edd848858342b43bd..e1c5a669b19bd4ec45ead0b6506e880d2cf107eb 100644 (file)
--- a/neutron/tests/unit/openvswitch/test_agent_scheduler.py
+++ b/neutron/tests/unit/openvswitch/test_agent_scheduler.py
@@ -576,6 +576,12 @@ class OvsAgentSchedulerTestCase(OvsAgentSchedulerTestCaseBase):
         self.assertEqual(1, num_before_remove)
         self.assertEqual(0, num_after_remove)
 
+    def test_list_active_networks_on_not_registered_yet_dhcp_agent(self):
+        plugin = manager.NeutronManager.get_plugin()
+        nets = plugin.list_active_networks_on_active_dhcp_agent(
+            self.adminContext, host=DHCP_HOSTA)
+        self.assertEqual([], nets)
+
     def test_reserved_port_after_network_remove_from_dhcp_agent(self):
         dhcp_hosta = {
             'binary': 'neutron-dhcp-agent',