Reset the compute_rpcapi in Compute manager on SIGHUP

This links Service.reset() to the manager, which for compute will
rebuild the compute_rpcapi and thus re-determine the appropriate
RPC versions.

Change-Id: Ifec7f6ff604d1e5f3663633065e9a55baacffec8

nova/compute/manager.py

@@ -718,6 +718,10 @@ class ComputeManager(manager.Manager):
         self.use_legacy_block_device_info = \
                             self.driver.need_legacy_block_device_info
 
+    def reset(self):
+        LOG.info(_LI('Reloading compute RPC API'))
+        self.compute_rpcapi = compute_rpcapi.ComputeAPI()
+
     def _get_resource_tracker(self, nodename):
         rt = self._resource_tracker_dict.get(nodename)
         if not rt:

nova/compute/rpcapi.py

@@ -333,7 +333,6 @@ class ComputeAPI(object):
         self.client = self.get_client(target, version_cap, serializer)
 
     def _determine_version_cap(self, target):
-        # FIXME(danms): We should reload this on SIGHUP, or by timer
         service_version = objects.Service.get_minimum_version(
             context.get_admin_context(), 'nova-compute')
         history = service_obj.SERVICE_VERSION_HISTORY

nova/manager.py

@@ -119,3 +119,9 @@ class Manager(base.Base, PeriodicTasks):
         Child classes should override this method.
         """
         pass
+
+    def reset(self):
+        """Hook called on SIGHUP to signal the manager to re-read any
+        dynamic configuration or do any reconfiguration tasks.
+        """
+        pass

nova/service.py

@@ -331,6 +331,9 @@ class Service(service.Service):
             LOG.error(_LE('Temporary directory is invalid: %s'), e)
             sys.exit(1)
 
+    def reset(self):
+        self.manager.reset()
+
 
 class WSGIService(service.Service):
     """Provides ability to launch API from a 'paste' configuration."""

nova/tests/unit/compute/test_compute_mgr.py

@@ -2867,6 +2867,13 @@ class ComputeManagerUnitTestCase(test.NoDBTestCase):
             mock_save.assert_called_once_with()
             mock_rt.assert_called_once_with(self.context, instance)
 
+    def test_reset_reloads_rpcapi(self):
+        orig_rpc = self.compute.compute_rpcapi
+        with mock.patch('nova.compute.rpcapi.ComputeAPI') as mock_rpc:
+            self.compute.reset()
+            mock_rpc.assert_called_once_with()
+            self.assertIsNot(orig_rpc, self.compute.compute_rpcapi)
+
 
 class ComputeManagerBuildInstanceTestCase(test.NoDBTestCase):
     def setUp(self):

nova/tests/unit/test_service.py

@@ -258,6 +258,15 @@ class ServiceTestCase(test.NoDBTestCase):
         serv.rpcserver.stop.assert_called_once_with()
         serv.rpcserver.wait.assert_called_once_with()
 
+    def test_reset(self):
+        serv = service.Service(self.host,
+                               self.binary,
+                               self.topic,
+                               'nova.tests.unit.test_service.FakeManager')
+        with mock.patch.object(serv.manager, 'reset') as mock_reset:
+            serv.reset()
+            mock_reset.assert_called_once_with()
+
 
 class TestWSGIService(test.NoDBTestCase):