Send a full instance via rpc for check_can_live_migrate_source.

Change the check_can_live_migrate_source method of the compute
rpc API to take a full instance over rpc instead of just the instance
UUID.  This cuts down on database access needed by nova-compute.

Part of blueprint no-db-messaging.

Change-Id: Ifc655fb86c94adc9a64e878a89a77342313cace2

4 files changed, 21 insertions, 14 deletions

diff --git a/nova/compute/manager.py b/nova/compute/manager.py
index 339dbcb5f..1a423a3c8 100644
--- a/nova/compute/manager.py
+++ b/nova/compute/manager.py
@@ -297,7 +297,7 @@ def _get_additional_capabilities():
 class ComputeManager(manager.SchedulerDependentManager):
     """Manages the running instances from creation to destruction."""
 
-    RPC_API_VERSION = '1.10'
+    RPC_API_VERSION = '1.11'
 
     def __init__(self, compute_driver=None, *args, **kwargs):
         """Load configuration options and connect to the hypervisor."""
@@ -2119,19 +2119,22 @@ class ComputeManager(manager.SchedulerDependentManager):
                     dest_check_data)
 
     @exception.wrap_exception(notifier=notifier, publisher_id=publisher_id())
-    def check_can_live_migrate_source(self, ctxt, instance_id,
-                                      dest_check_data):
+    def check_can_live_migrate_source(self, ctxt, dest_check_data,
+                                      instance_id=None, instance=None):
         """Check if it is possible to execute live migration.
 
         This checks if the live migration can succeed, based on the
         results from check_can_live_migrate_destination.
 
         :param context: security context
-        :param instance_id: nova.db.sqlalchemy.models.Instance.Id
+        :param instance: dict of instance data
+        :param instance_id: (deprecated and only supplied if no instance passed
+                             in) nova.db.sqlalchemy.models.Instance.Id
         :param dest_check_data: result of check_can_live_migrate_destination
         """
-        instance_ref = self.db.instance_get(ctxt, instance_id)
-        self.driver.check_can_live_migrate_source(ctxt, instance_ref,
+        if not instance:
+            instance = self.db.instance_get(ctxt, instance_id)
+        self.driver.check_can_live_migrate_source(ctxt, instance,
                                                   dest_check_data)
 
     def pre_live_migration(self, context, instance_id,
diff --git a/nova/compute/rpcapi.py b/nova/compute/rpcapi.py
index 89a9e9e5f..9644781f4 100644
--- a/nova/compute/rpcapi.py
+++ b/nova/compute/rpcapi.py
@@ -70,6 +70,8 @@ class ComputeAPI(nova.openstack.common.rpc.proxy.RpcProxy):
         1.9 - Remove instance_uuid, add instance argument to attach_volume()
         1.10 - Remove instance_id, add instance argument to
                check_can_live_migrate_destination()
+        1.11 - Remove instance_id, add instance argument to
+               check_can_live_migrate_source()
     '''
 
     BASE_RPC_API_VERSION = '1.0'
@@ -118,11 +120,12 @@ class ComputeAPI(nova.openstack.common.rpc.proxy.RpcProxy):
                   version='1.10')
 
     def check_can_live_migrate_source(self, ctxt, instance, dest_check_data):
+        instance_p = jsonutils.to_primitive(instance)
         self.call(ctxt, self.make_msg('check_can_live_migrate_source',
-                           instance_id=instance['id'],
+                           instance=instance_p,
                            dest_check_data=dest_check_data),
                   topic=_compute_topic(self.topic, ctxt, None, instance),
-                  version='1.2')
+                  version='1.11')
 
     def check_shared_storage_test_file(self, ctxt, filename, host):
         raise rpc_common.RPCException(message=_('Deprecated from version 1.2'))
diff --git a/nova/tests/compute/test_compute.py b/nova/tests/compute/test_compute.py
index e2c736c54..6ccf2e312 100644
--- a/nova/tests/compute/test_compute.py
+++ b/nova/tests/compute/test_compute.py
@@ -1404,7 +1404,8 @@ class ComputeTestCase(BaseTestCase):
     def test_check_can_live_migrate_source_works_correctly(self):
         """Confirm check_can_live_migrate_source works on positive path"""
         context = self.context.elevated()
-        inst_ref = self._create_fake_instance({'host': 'fake_host_2'})
+        inst_ref = jsonutils.to_primitive(self._create_fake_instance(
+                                          {'host': 'fake_host_2'}))
         inst_id = inst_ref["id"]
         dest = "fake_host_1"
 
@@ -1413,14 +1414,13 @@ class ComputeTestCase(BaseTestCase):
                                  'check_can_live_migrate_source')
 
         dest_check_data = {"test": "data"}
-        db.instance_get(context, inst_id).AndReturn(inst_ref)
         self.compute.driver.check_can_live_migrate_source(context,
                                                           inst_ref,
                                                           dest_check_data)
 
         self.mox.ReplayAll()
-        self.compute.check_can_live_migrate_source(context, inst_id,
-                                                   dest_check_data)
+        self.compute.check_can_live_migrate_source(context,
+                dest_check_data=dest_check_data, instance=inst_ref)
 
     def test_check_can_live_migrate_destination_works_correctly(self):
         """Confirm check_can_live_migrate_destination works on positive path"""
diff --git a/nova/tests/compute/test_rpcapi.py b/nova/tests/compute/test_rpcapi.py
index 6d9e32fc7..9be465ca9 100644
--- a/nova/tests/compute/test_rpcapi.py
+++ b/nova/tests/compute/test_rpcapi.py
@@ -50,7 +50,8 @@ class ComputeRpcAPITestCase(test.TestCase):
 
         methods_with_instance = [
             'add_fixed_ip_to_instance', 'attach_volume',
-            'check_can_live_migrate_destination', 'get_console_output',
+            'check_can_live_migrate_destination',
+            'check_can_live_migrate_source', 'get_console_output',
             'pause_instance', 'reboot_instance', 'suspend_instance',
             'unpause_instance'
         ]
@@ -139,7 +140,7 @@ class ComputeRpcAPITestCase(test.TestCase):
 
     def test_check_can_live_migrate_source(self):
         self._test_compute_api('check_can_live_migrate_source', 'call',
-                version='1.2', instance=self.fake_instance,
+                version='1.11', instance=self.fake_instance,
                 dest_check_data={"test": "data"})
 
     def test_confirm_resize_cast(self):