Don't throw NotConnectedError in queue_txn

Before Ifc74a834ca1a7d914c7ca66d71b47694f9eef1e5, queueing a
transaction before we had connected to an ovsdb-server would
happily work. When the connection started, the run() method would
pull the queued transaction off the queue and process it. Adding
the exception added a race condition in existing code, so this
patch removes it.

Change-Id: I0b620b0040ef5f7cb99d2f27140f605e97f95512
Related-Bug: #1731063

ovsdbapp/backend/ovs_idl/connection.py

@@ -21,7 +21,6 @@ from ovs import poller
 from six.moves import queue as Queue
 
 from ovsdbapp.backend.ovs_idl import idlutils
-from ovsdbapp import exceptions
 
 if os.name == 'nt':
     from ovsdbapp.backend.ovs_idl.windows import connection_utils
@@ -116,8 +115,8 @@ class Connection(object):
         return True
 
     def queue_txn(self, txn):
-        if not self._is_running:
-            raise exceptions.NotConnectedError(txn=txn)
+        # Even if we aren't started, we can queue a transaction and it will
+        # run when we are started
         self.txns.put(txn)
 
 

ovsdbapp/exceptions.py

@@ -59,7 +59,3 @@ class OvsdbConnectionUnavailable(OvsdbAppException):
                "'%(error)s'. Verify that the OVS and OVN services are "
                "available and that the 'ovn_nb_connection' and "
                "'ovn_sb_connection' configuration options are correct.")
-
-
-class NotConnectedError(OvsdbAppException):
-    message = "Cannot commit transaction %(txn)s. Not connected"

ovsdbapp/tests/functional/schema/open_vswitch/test_impl_idl.py

@@ -104,11 +104,12 @@ class TestOvsdbIdl(base.FunctionalTestCase):
     def test_connection_reconnect(self):
         self.api.ovsdb_connection.stop()
         existsCmd = self.api.br_exists(self.brname)
-        self.assertRaises(exc.NotConnectedError,
-                          existsCmd.execute, check_error=True)
+        txn = self.api.create_transaction(check_error=True)
+        txn.add(existsCmd)
+        self.api.ovsdb_connection.queue_txn(txn)
         self.api.ovsdb_connection.start()
-        exists = self.api.br_exists(self.brname).execute(check_error=True)
-        self.assertFalse(exists)
+        result = txn.results.get(timeout=self.api.ovsdb_connection.timeout)
+        self.assertEqual(result, [False])
 
     def test_connection_disconnect_timeout(self):
         _is_running_mock = mock.PropertyMock(return_value=True)