Use Service object instead of DB API directly

In cmd.manage and volume.api we had code accessing DB API directly.
This should be done through Service versioned object instead and this
commit fixes that.

Change-Id: I7c65323279b86c37fce7ffeb2b2626508842edfb
Closes-Bug: 1513806

cinder/cmd/manage.py

@@ -466,8 +466,8 @@ class ServiceCommands(object):
         """Completely removes a service."""
         ctxt = context.get_admin_context()
         try:
-            svc = db.service_get_by_args(ctxt, host_name, binary)
-            db.service_destroy(ctxt, svc['id'])
+            svc = objects.Service.get_by_args(ctxt, host_name, binary)
+            svc.destroy()
         except exception.HostBinaryNotFound as e:
             print(_("Host not found. Failed to remove %(service)s"
                     " on %(host)s.") %

cinder/tests/unit/api/contrib/test_snapshot_manage.py

@@ -20,6 +20,7 @@ from cinder import context
 from cinder import exception
 from cinder import test
 from cinder.tests.unit.api import fakes
+from cinder.tests.unit import fake_service
 
 
 def app():
@@ -77,6 +78,9 @@ class SnapshotManageTest(test.TestCase):
         called with the correct arguments, and that we return the correct HTTP
         code to the caller.
         """
+        ctxt = context.RequestContext('admin', 'fake', True)
+        mock_db.return_value = fake_service.fake_service_obj(ctxt)
+
         body = {'snapshot': {'volume_id': 'fake_volume_id', 'ref': 'fake_ref'}}
         res = self._get_resp(body)
         self.assertEqual(202, res.status_int, res)

cinder/tests/unit/test_cmd.py

@@ -802,7 +802,7 @@ class TestCinderManageCmd(test.TestCase):
 
     @mock.patch('cinder.db.service_destroy')
     @mock.patch('cinder.db.service_get_by_args',
-                return_value = {'id': 'volID'})
+                return_value = {'id': '12'})
     def test_remove_service_success(self, mock_get_by_args,
                                     mock_service_destroy):
         service_commands = cinder_manage.ServiceCommands()

cinder/volume/api.py

@@ -1598,8 +1598,8 @@ class API(base.Base):
                                  metadata=None):
         host = volume_utils.extract_host(volume['host'])
         try:
-            self.db.service_get_by_host_and_topic(
-                context.elevated(), host, CONF.volume_topic)
+            objects.Service.get_by_host_and_topic(context.elevated(), host,
+                                                  CONF.volume_topic)
         except exception.ServiceNotFound:
             with excutils.save_and_reraise_exception():
                 LOG.error(_LE('Unable to find service: %(service)s for '