KafkaClient.connection_delay should return 0 when connecting to avoid unnecessary sleep in poll

kafka/client_async.py

@@ -231,11 +231,15 @@ class KafkaClient(object):
         """
         Returns the number of milliseconds to wait, based on the connection
         state, before attempting to send data. When disconnected, this respects
-        the reconnect backoff time. When connecting or connected, this handles
-        slow/stalled connections.
+        the reconnect backoff time. When connecting, returns 0 to allow
+        non-blocking connect to finish. When connected, returns a very large
+        number to handle slow/stalled connections.
 
-        @param node_id The id of the node to check
-        @return The number of milliseconds to wait.
+        Arguments:
+            node_id (int): The id of the node to check
+
+        Returns:
+            int: The number of milliseconds to wait.
         """
         if node_id not in self._conns:
             return 0
@@ -244,6 +248,8 @@ class KafkaClient(object):
         time_waited_ms = time.time() - (conn.last_attempt or 0)
         if conn.state is ConnectionStates.DISCONNECTED:
             return max(self.config['reconnect_backoff_ms'] - time_waited_ms, 0)
+        elif conn.state is ConnectionStates.CONNECTING:
+            return 0
         else:
             return 999999999