Handle service creation race by service workers

This handle a race where a sibling has already created the service
record in the database.  This fix is similar to that of commit
f6c341b.

Change-Id: I7975fc632eee34390c5d7dc275b52363ad45475e
Closes-bug: 1326901
(cherry picked from commit 37247ab)

nova/service.py

@@ -170,7 +170,8 @@ def start(self):
         except exception.NotFound:
             try:
                 self.service_ref = self._create_service_ref(ctxt)
-            except exception.ServiceTopicExists:
+            except (exception.ServiceTopicExists,
+                    exception.ServiceBinaryExists):
                 # NOTE(danms): If we race to create a record with a sibling
                 # worker, don't fail here.
                 self.service_ref = self.conductor_api.service_get_by_args(ctxt,

nova/tests/test_service.py

@@ -186,7 +186,7 @@ def test_init_and_start_hooks(self):
                                'nova.tests.test_service.FakeManager')
         serv.start()
 
-    def test_service_check_create_race(self):
+    def _test_service_check_create_race(self, ex):
         self.manager_mock = self.mox.CreateMock(FakeManager)
         self.mox.StubOutWithMock(sys.modules[__name__], 'FakeManager',
                                  use_mock_anything=True)
@@ -201,7 +201,6 @@ def test_service_check_create_race(self):
 
         db.service_get_by_args(mox.IgnoreArg(), self.host, self.binary
                                ).AndRaise(exception.NotFound)
-        ex = exception.ServiceTopicExists(host='foo', topic='bar')
         db.service_create(mox.IgnoreArg(), mox.IgnoreArg()
                           ).AndRaise(ex)
 
@@ -219,6 +218,14 @@ class TestException(Exception):
                                'nova.tests.test_service.FakeManager')
         self.assertRaises(TestException, serv.start)
 
+    def test_service_check_create_race_topic_exists(self):
+        ex = exception.ServiceTopicExists(host='foo', topic='bar')
+        self._test_service_check_create_race(ex)
+
+    def test_service_check_create_race_binary_exists(self):
+        ex = exception.ServiceBinaryExists(host='foo', binary='bar')
+        self._test_service_check_create_race(ex)
+
     def test_parent_graceful_shutdown(self):
         self.manager_mock = self.mox.CreateMock(FakeManager)
         self.mox.StubOutWithMock(sys.modules[__name__],