make Sender._topics_to_add a set instead of a list

1 files changed, 4 insertions, 3 deletions

diff --git a/kafka/producer/sender.py b/kafka/producer/sender.py
index 0e6d6cd..bba135b 100644
--- a/kafka/producer/sender.py
+++ b/kafka/producer/sender.py
@@ -45,7 +45,7 @@ class Sender(threading.Thread):
         self._metadata = client.cluster
         self._running = True
         self._force_close = False
-        self._topics_to_add = []
+        self._topics_to_add = set()
 
     def run(self):
         """The main run loop for the sender thread."""
@@ -158,8 +158,9 @@ class Sender(threading.Thread):
         self.initiate_close()
 
     def add_topic(self, topic):
-        self._topics_to_add.append(topic)
-        self.wakeup()
+        if topic not in self._topics_to_add:
+            self._topics_to_add.add(topic)
+            self.wakeup()
 
     def _failed_produce(self, batches, node_id, error):
         log.debug("Error sending produce request to node %d: %s", node_id, error) # trace