Fix bugs and testing

* Ensure that round-robin partitioner works fine
* _load_metadata_for_topics() would cause duplicate and stale entries in
  self.topic_partitions. Fix this

kafka/client.py

@@ -73,7 +73,12 @@ class KafkaClient(object):
 
         self.brokers.update(brokers)
         self.topics_to_brokers = {}
+
         for topic, partitions in topics.items():
+            # Clear the list once before we add it. This removes stale entries
+            # and avoids duplicates
+            self.topic_partitions.pop(topic, None)
+
             if not partitions:
                 log.info("Partition is unassigned, delay for 1s and retry")
                 time.sleep(1)

kafka/partitioner.py

@@ -31,14 +31,18 @@ class RoundRobinPartitioner(Partitioner):
     in a round robin fashion
     """
     def __init__(self, partitions):
-        self.partitions = cycle(partitions)
+        self._set_partitions(partitions)
+
+    def _set_partitions(self, partitions):
+        self.partitions = partitions
+        self.iterpart = cycle(partitions)
 
     def partition(self, key, partitions):
         # Refresh the partition list if necessary
         if self.partitions != partitions:
-            self.partitions = cycle(partitions)
+            self._set_partitions(partitions)
 
-        return self.partitions.next()
+        return self.iterpart.next()
 
 
 class HashedPartitioner(Partitioner):

kafka/producer.py

@@ -46,8 +46,8 @@ class KeyedProducer(object):
 
         self.partitioner = partitioner(self.client.topic_partitions[topic])
 
-    def send(self, client, key, msg):
-        partitions = self.client.topic_partitions[topic]
+    def send(self, key, msg):
+        partitions = self.client.topic_partitions[self.topic]
         partition = self.partitioner.partition(key, partitions)
 
         req = ProduceRequest(self.topic, partition,