Only increase reconnect backoff if all addrinfos have been tried (#1423)

Author: dpkp

kafka/conn.py

@@ -264,7 +264,7 @@ def __init__(self, host, port, afi, **configs):
             self._ssl_context = self.config['ssl_context']
         self._sasl_auth_future = None
         self.last_attempt = 0
-        self._gai = None
+        self._gai = []
         self._sensors = None
         if self.config['metrics']:
             self._sensors = BrokerConnectionMetrics(self.config['metrics'],
@@ -638,6 +638,9 @@ def _reset_reconnect_backoff(self):
         self._reconnect_backoff = self.config['reconnect_backoff_ms'] / 1000.0
 
     def _update_reconnect_backoff(self):
+        # Do not mark as failure if there are more dns entries available to try
+        if len(self._gai) > 0:
+            return
         if self.config['reconnect_backoff_max_ms'] > self.config['reconnect_backoff_ms']:
             self._failures += 1
             self._reconnect_backoff = self.config['reconnect_backoff_ms'] * 2 ** (self._failures - 1)