Send a full instance via rpc for attach_volume.

Change the attach_volume 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: I85ad29e84b5e97a3f918059b10e2309312756050

3 files changed, 22 insertions, 15 deletions

diff --git a/nova/compute/manager.py b/nova/compute/manager.py
index 097905788..afe8cae51 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 = '1.8'
+    RPC_API_VERSION = '1.9'
 
     def __init__(self, compute_driver=None, *args, **kwargs):
         """Load configuration options and connect to the hypervisor."""
@@ -1961,15 +1961,17 @@ class ComputeManager(manager.SchedulerDependentManager):
     @exception.wrap_exception(notifier=notifier, publisher_id=publisher_id())
     @checks_instance_lock
     @wrap_instance_fault
-    def attach_volume(self, context, instance_uuid, volume_id, mountpoint):
+    def attach_volume(self, context, volume_id, mountpoint, instance_uuid=None,
+                      instance=None):
         """Attach a volume to an instance."""
         volume = self.volume_api.get(context, volume_id)
         context = context.elevated()
-        instance_ref = self.db.instance_get_by_uuid(context, instance_uuid)
+        if not instance:
+            instance = self.db.instance_get_by_uuid(context, instance_uuid)
         LOG.audit(_('Attaching volume %(volume_id)s to %(mountpoint)s'),
-                  locals(), context=context, instance=instance_ref)
+                  locals(), context=context, instance=instance)
         try:
-            connector = self.driver.get_volume_connector(instance_ref)
+            connector = self.driver.get_volume_connector(instance)
             connection_info = self.volume_api.initialize_connection(context,
                                                                     volume,
                                                                     connector)
@@ -1978,28 +1980,28 @@ class ComputeManager(manager.SchedulerDependentManager):
                 msg = _("Failed to connect to volume %(volume_id)s "
                         "while attaching at %(mountpoint)s")
                 LOG.exception(msg % locals(), context=context,
-                              instance=instance_ref)
+                              instance=instance)
                 self.volume_api.unreserve_volume(context, volume)
         try:
             self.driver.attach_volume(connection_info,
-                                      instance_ref['name'],
+                                      instance['name'],
                                       mountpoint)
         except Exception:  # pylint: disable=W0702
             with excutils.save_and_reraise_exception():
                 msg = _("Failed to attach volume %(volume_id)s "
                         "at %(mountpoint)s")
                 LOG.exception(msg % locals(), context=context,
-                              instance=instance_ref)
+                              instance=instance)
                 self.volume_api.terminate_connection(context,
                                                      volume,
                                                      connector)
 
         self.volume_api.attach(context,
                                volume,
-                               instance_ref['uuid'],
+                               instance['uuid'],
                                mountpoint)
         values = {
-            'instance_uuid': instance_ref['uuid'],
+            'instance_uuid': instance['uuid'],
             'connection_info': jsonutils.dumps(connection_info),
             'device_name': mountpoint,
             'delete_on_termination': False,
diff --git a/nova/compute/rpcapi.py b/nova/compute/rpcapi.py
index 726b520b5..b11b17144 100644
--- a/nova/compute/rpcapi.py
+++ b/nova/compute/rpcapi.py
@@ -67,6 +67,7 @@ class ComputeAPI(nova.openstack.common.rpc.proxy.RpcProxy):
               get_console_output()
         1.8 - Remove instance_uuid, add instance argument to
               add_fixed_ip_to_instance()
+        1.9 - Remove instance_uuid, add instance argument to attach_volume()
     '''
 
     BASE_RPC_API_VERSION = '1.0'
@@ -97,10 +98,12 @@ class ComputeAPI(nova.openstack.common.rpc.proxy.RpcProxy):
                 version='1.8')
 
     def attach_volume(self, ctxt, instance, volume_id, mountpoint):
+        instance_p = jsonutils.to_primitive(instance)
         self.cast(ctxt, self.make_msg('attach_volume',
-                instance_uuid=instance['uuid'], volume_id=volume_id,
+                instance=instance_p, volume_id=volume_id,
                 mountpoint=mountpoint),
-                topic=_compute_topic(self.topic, ctxt, None, instance))
+                topic=_compute_topic(self.topic, ctxt, None, instance),
+                version='1.9')
 
     def check_can_live_migrate_destination(self, ctxt, instance, destination,
             block_migration, disk_over_commit):
diff --git a/nova/tests/compute/test_rpcapi.py b/nova/tests/compute/test_rpcapi.py
index b5319d257..ee74f2c6b 100644
--- a/nova/tests/compute/test_rpcapi.py
+++ b/nova/tests/compute/test_rpcapi.py
@@ -49,8 +49,9 @@ class ComputeRpcAPITestCase(test.TestCase):
         ctxt = context.RequestContext('fake_user', 'fake_project')
 
         methods_with_instance = [
-            'add_fixed_ip_to_instance', 'get_console_output', 'pause_instance',
-            'reboot_instance', 'suspend_instance', 'unpause_instance'
+            'add_fixed_ip_to_instance', 'attach_volume', 'get_console_output',
+            'pause_instance', 'reboot_instance', 'suspend_instance',
+            'unpause_instance'
         ]
 
         if 'rpcapi_class' in kwargs:
@@ -126,7 +127,8 @@ class ComputeRpcAPITestCase(test.TestCase):
 
     def test_attach_volume(self):
         self._test_compute_api('attach_volume', 'cast',
-                instance=self.fake_instance, volume_id='id', mountpoint='mp')
+                instance=self.fake_instance, volume_id='id', mountpoint='mp',
+                version='1.9')
 
     def test_check_can_live_migrate_destination(self):
         self._test_compute_api('check_can_live_migrate_destination', 'call',