Use conductor for migration_get()

This patch removes direct database accesses for looking up
migrations by id, and instead queries conductor.

Related to blueprint no-db-compute

Change-Id: Ia7df121971b14b1eb4ce65063246968b3603309d

5 files changed, 30 insertions, 11 deletions

diff --git a/nova/compute/manager.py b/nova/compute/manager.py
index fd8dc7d17..f0c0fe961 100644
--- a/nova/compute/manager.py
+++ b/nova/compute/manager.py
@@ -1625,8 +1625,7 @@ class ComputeManager(manager.SchedulerDependentManager):
                        migration=None, migration_id=None):
         """Destroys the source instance."""
         if not migration:
-            migration = self.db.migration_get(context.elevated(),
-                    migration_id)
+            migration = self.conductor_api.migration_get(context, migration_id)
 
         self._notify_about_instance_usage(context, instance,
                                           "resize.confirm.start")
@@ -1662,8 +1661,7 @@ class ComputeManager(manager.SchedulerDependentManager):
 
         """
         if not migration:
-            migration = self.db.migration_get(context.elevated(),
-                                                  migration_id)
+            migration = self.conductor_api.migration_get(context, migration_id)
 
         # NOTE(comstud): A revert_resize is essentially a resize back to
         # the old size, so we need to send a usage event here.
@@ -1706,10 +1704,8 @@ class ComputeManager(manager.SchedulerDependentManager):
         in the database.
 
         """
-        elevated = context.elevated()
-
         if not migration:
-            migration = self.db.migration_get(elevated, migration_id)
+            migration = self.conductor_api.migration_get(context, migration_id)
 
         with self._error_out_instance_on_exception(context, instance['uuid'],
                                                    reservations):
@@ -1889,7 +1885,7 @@ class ComputeManager(manager.SchedulerDependentManager):
                         instance_type=None):
         """Starts the migration of a running instance to another host."""
         if not migration:
-            migration = self.db.migration_get(context.elevated(), migration_id)
+            migration = self.conductor_api.migration_get(context, migration_id)
         with self._error_out_instance_on_exception(context, instance['uuid'],
                                                    reservations):
             if not instance_type:
@@ -2026,8 +2022,7 @@ class ComputeManager(manager.SchedulerDependentManager):
 
         """
         if not migration:
-            migration = self.db.migration_get(context.elevated(),
-                    migration_id)
+            migration = self.conductor_api.migration_get(context, migration_id)
         try:
             self._finish_resize(context, instance, migration,
                                 disk_info, image)
diff --git a/nova/conductor/api.py b/nova/conductor/api.py
index ddbd64d03..781a6ea90 100644
--- a/nova/conductor/api.py
+++ b/nova/conductor/api.py
@@ -53,6 +53,9 @@ class LocalAPI(object):
     def instance_get_all_by_host(self, context, host):
         return self._manager.instance_get_all_by_host(context, host)
 
+    def migration_get(self, context, migration_id):
+        return self._manager.migration_get(context, migration_id)
+
     def migration_update(self, context, migration, status):
         return self._manager.migration_update(context, migration, status)
 
@@ -81,6 +84,9 @@ class API(object):
     def instance_get_all_by_host(self, context, host):
         return self.conductor_rpcapi.instance_get_all_by_host(context, host)
 
+    def migration_get(self, context, migration_id):
+        return self.conductor_rpcapi.migration_get(context, migration_id)
+
     def migration_update(self, context, migration, status):
         return self.conductor_rpcapi.migration_update(context, migration,
                                                       status)
diff --git a/nova/conductor/manager.py b/nova/conductor/manager.py
index 824875b3c..ce76fe02d 100644
--- a/nova/conductor/manager.py
+++ b/nova/conductor/manager.py
@@ -41,7 +41,7 @@ datetime_fields = ['launched_at', 'terminated_at']
 class ConductorManager(manager.SchedulerDependentManager):
     """Mission: TBD"""
 
-    RPC_API_VERSION = '1.3'
+    RPC_API_VERSION = '1.4'
 
     def __init__(self, *args, **kwargs):
         super(ConductorManager, self).__init__(service_name='conductor',
@@ -69,6 +69,11 @@ class ConductorManager(manager.SchedulerDependentManager):
         return jsonutils.to_primitive(
             self.db.instance_get_all_by_host(context.elevated(), host))
 
+    def migration_get(self, context, migration_id):
+        migration_ref = self.db.migration_get(context.elevated(),
+                                              migration_id)
+        return jsonutils.to_primitive(migration_ref)
+
     def migration_update(self, context, migration, status):
         migration_ref = self.db.migration_update(context.elevated(),
                                                  migration['id'],
diff --git a/nova/conductor/rpcapi.py b/nova/conductor/rpcapi.py
index ae82856e4..0ca1269c4 100644
--- a/nova/conductor/rpcapi.py
+++ b/nova/conductor/rpcapi.py
@@ -30,6 +30,7 @@ class ConductorAPI(nova.openstack.common.rpc.proxy.RpcProxy):
     1.1 - Added migration_update
     1.2 - Added instance_get_by_uuid and instance_get_all_by_host
     1.3 - Added aggregate_host_add and aggregate_host_delete
+    1.4 - Added migration_get
     """
 
     BASE_RPC_API_VERSION = '1.0'
@@ -55,6 +56,10 @@ class ConductorAPI(nova.openstack.common.rpc.proxy.RpcProxy):
         msg = self.make_msg('instance_get_all_by_host', host=host)
         return self.call(context, msg, version='1.2')
 
+    def migration_get(self, context, migration_id):
+        msg = self.make_msg('migration_get', migration_id=migration_id)
+        return self.call(context, msg, version='1.4')
+
     def migration_update(self, context, migration, status):
         migration_p = jsonutils.to_primitive(migration)
         msg = self.make_msg('migration_update', migration=migration_p,
diff --git a/nova/tests/conductor/test_conductor.py b/nova/tests/conductor/test_conductor.py
index 880a3a717..8c97c4cdc 100644
--- a/nova/tests/conductor/test_conductor.py
+++ b/nova/tests/conductor/test_conductor.py
@@ -90,6 +90,14 @@ class ConductorTestCase(BaseTestCase):
             self.assertRaises(KeyError,
                               self._do_update, 'any-uuid', foobar=1)
 
+    def test_migration_get(self):
+        migration = db.migration_create(self.context.elevated(),
+                {'instance_uuid': 'fake-uuid',
+                 'status': 'migrating'})
+        self.assertEqual(jsonutils.to_primitive(migration),
+                         self.conductor.migration_get(self.context,
+                                                      migration['id']))
+
     def test_migration_update(self):
         migration = db.migration_create(self.context.elevated(),
                 {'instance_uuid': 'fake-uuid',