Merge "Fix DetachedInstanceError for Agent instance"

neutron/scheduler/dhcp_agent_scheduler.py

@@ -35,22 +35,25 @@ class ChanceScheduler(object):
     can be introduced later.
     """
 
-    def _schedule_bind_network(self, context, agent, network_id):
+    def _schedule_bind_network(self, context, agents, network_id):
-        try:
+        for agent in agents:
-            binding = agentschedulers_db.NetworkDhcpAgentBinding()
+            context.session.begin(subtransactions=True)
-            binding.dhcp_agent = agent
+            try:
-            binding.network_id = network_id
+                binding = agentschedulers_db.NetworkDhcpAgentBinding()
-            context.session.add(binding)
+                binding.dhcp_agent = agent
-            # try to actually write the changes and catch integrity
+                binding.network_id = network_id
-            # DBDuplicateEntry
+                context.session.add(binding)
-            context.session.flush()
+                # try to actually write the changes and catch integrity
-        except db_exc.DBDuplicateEntry:
+                # DBDuplicateEntry
-            # it's totally ok, someone just did our job!
+                context.session.commit()
-            pass
+            except db_exc.DBDuplicateEntry:
-        LOG.debug(_('Network %(network_id)s is scheduled to be hosted by '
+                # it's totally ok, someone just did our job!
-                    'DHCP agent %(agent_id)s'),
+                context.session.rollback()
-                  {'network_id': network_id,
+                LOG.info(_('Agent %s already present'), agent)
-                   'agent_id': agent})
+            LOG.debug(_('Network %(network_id)s is scheduled to be '
+                        'hosted by DHCP agent %(agent_id)s'),
+                      {'network_id': network_id,
+                       'agent_id': agent})
 
     def schedule(self, plugin, context, network):
         """Schedule the network to active DHCP agent(s).
@@ -87,8 +90,7 @@ class ChanceScheduler(object):
                 return
             n_agents = min(len(active_dhcp_agents), n_agents)
             chosen_agents = random.sample(active_dhcp_agents, n_agents)
-            for agent in chosen_agents:
+        self._schedule_bind_network(context, chosen_agents, network['id'])
-                self._schedule_bind_network(context, agent, network['id'])
         return chosen_agents
 
     def auto_schedule_networks(self, plugin, context, host):

neutron/tests/unit/test_dhcp_scheduler.py

@@ -0,0 +1,90 @@
+# Copyright 2014 OpenStack Foundation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import mock
+
+from neutron.common import constants
+from neutron.common import topics
+from neutron import context
+from neutron.db import agents_db
+from neutron.db import agentschedulers_db
+from neutron.db import api as db
+from neutron.db import models_v2
+from neutron.openstack.common import timeutils
+from neutron.scheduler import dhcp_agent_scheduler
+from neutron.tests import base
+
+
+class DhcpSchedulerTestCase(base.BaseTestCase):
+
+    def setUp(self):
+        super(DhcpSchedulerTestCase, self).setUp()
+        db.configure_db()
+        self.ctx = context.get_admin_context()
+        self.network_id = 'foo_network_id'
+        self._save_networks([self.network_id])
+        self.addCleanup(db.clear_db)
+
+    def _get_agents(self, hosts):
+        return [
+            agents_db.Agent(
+                binary='neutron-dhcp-agent',
+                host=host,
+                topic=topics.DHCP_AGENT,
+                configurations="",
+                agent_type=constants.AGENT_TYPE_DHCP,
+                created_at=timeutils.utcnow(),
+                started_at=timeutils.utcnow(),
+                heartbeat_timestamp=timeutils.utcnow())
+            for host in hosts
+        ]
+
+    def _save_agents(self, agents):
+        for agent in agents:
+            with self.ctx.session.begin(subtransactions=True):
+                self.ctx.session.add(agent)
+
+    def _save_networks(self, networks):
+        for network_id in networks:
+            with self.ctx.session.begin(subtransactions=True):
+                self.ctx.session.add(models_v2.Network(id=network_id))
+
+    def _test__schedule_bind_network(self, agents, network_id):
+        scheduler = dhcp_agent_scheduler.ChanceScheduler()
+        scheduler._schedule_bind_network(self.ctx, agents, network_id)
+        results = (
+            self.ctx.session.query(agentschedulers_db.NetworkDhcpAgentBinding).
+            filter_by(network_id=network_id).all())
+        self.assertEqual(len(agents), len(results))
+        for result in results:
+            self.assertEqual(network_id, result.network_id)
+
+    def test__schedule_bind_network_single_agent(self):
+        agents = self._get_agents(['host-a'])
+        self._save_agents(agents)
+        self._test__schedule_bind_network(agents, self.network_id)
+
+    def test__schedule_bind_network_multi_agents(self):
+        agents = self._get_agents(['host-a', 'host-b'])
+        self._save_agents(agents)
+        self._test__schedule_bind_network(agents, self.network_id)
+
+    def test__schedule_bind_network_multi_agent_fail_one(self):
+        agents = self._get_agents(['host-a'])
+        self._save_agents(agents)
+        self._test__schedule_bind_network(agents, self.network_id)
+        with mock.patch.object(dhcp_agent_scheduler.LOG, 'info') as fake_log:
+            self._test__schedule_bind_network(agents, self.network_id)
+            self.assertEqual(1, fake_log.call_count)