connection: tolerate clean startup close

Author: dkropachev

cassandra/connection.py

@@ -986,8 +986,6 @@ def factory(cls, endpoint, timeout, host_conn = None, *args, **kwargs):
             conn.close()
             raise OperationTimedOut("Timed out creating connection (%s seconds)" % timeout,
                                     timeout=timeout)
-        elif conn.is_closed:
-            raise ConnectionShutdown("Connection to %s was closed by server" % conn.endpoint)
         else:
             return conn
 

tests/unit/test_connection.py

@@ -383,6 +383,30 @@ def test_wait_for_responses_shutdown_includes_last_error(self):
         assert "already closed" in error_message
         assert "Bad file descriptor" in error_message
 
+    def test_factory_returns_cleanly_closed_connection(self):
+        """
+        Clean server closes during startup are left for the owning pool/control
+        connection to handle so reconnection cadence stays centralized.
+        """
+
+        class ClosedConnection(Connection):
+            created = None
+
+            def __init__(self, *args, **kwargs):
+                super(ClosedConnection, self).__init__(*args, **kwargs)
+                self.is_closed = True
+                self.connected_event.set()
+                ClosedConnection.created = self
+
+            def close(self):
+                self.is_closed = True
+                self.connected_event.set()
+
+        conn = ClosedConnection.factory(DefaultEndPoint('1.2.3.4'), timeout=1)
+
+        assert conn is ClosedConnection.created
+        assert conn.is_closed
+
 
 @patch('cassandra.connection.ConnectionHeartbeat._raise_if_stopped')
 class ConnectionHeartbeatTest(unittest.TestCase):