Rollover KafkaClient correlation ids at 2**31 to keep within int32 protocol encoding

kafka/client.py

@@ -2,7 +2,6 @@ import binascii
 import collections
 import copy
 import functools
-import itertools
 import logging
 import time
 import kafka.common
@@ -23,17 +22,18 @@ log = logging.getLogger("kafka")
 class KafkaClient(object):
 
     CLIENT_ID = b"kafka-python"
-    ID_GEN = itertools.count()
 
     # NOTE: The timeout given to the client should always be greater than the
     # one passed to SimpleConsumer.get_message(), otherwise you can get a
     # socket timeout.
     def __init__(self, hosts, client_id=CLIENT_ID,
-                 timeout=DEFAULT_SOCKET_TIMEOUT_SECONDS):
+                 timeout=DEFAULT_SOCKET_TIMEOUT_SECONDS,
+                 correlation_id=0):
         # We need one connection to bootstrap
         self.client_id = kafka_bytestring(client_id)
         self.timeout = timeout
         self.hosts = collect_hosts(hosts)
+        self.correlation_id = correlation_id
 
         # create connections only when we need them
         self.conns = {}
@@ -98,10 +98,10 @@ class KafkaClient(object):
         return self.brokers[meta.leader]
 
     def _next_id(self):
-        """
-        Generate a new correlation id
-        """
-        return next(KafkaClient.ID_GEN)
+        """Generate a new correlation id"""
+        # modulo to keep w/i int32
+        self.correlation_id = (self.correlation_id + 1) % 2**31
+        return self.correlation_id
 
     def _send_broker_unaware_request(self, payloads, encoder_fn, decoder_fn):
         """