Disable default consumer group (#1016)

kafka/consumer/group.py

@@ -53,7 +53,7 @@ class KafkaConsumer(six.Iterator):
             partition assignment (if enabled), and to use for fetching and
             committing offsets. If None, auto-partition assignment (via
             group coordinator) and offset commits are disabled.
-            Default: 'kafka-python-default-group'
+            Default: None
         key_deserializer (callable): Any callable that takes a
             raw message key and returns a deserialized key.
         value_deserializer (callable): Any callable that takes a
@@ -215,7 +215,7 @@ class KafkaConsumer(six.Iterator):
     DEFAULT_CONFIG = {
         'bootstrap_servers': 'localhost',
         'client_id': 'kafka-python-' + __version__,
-        'group_id': 'kafka-python-default-group',
+        'group_id': None,
         'key_deserializer': None,
         'value_deserializer': None,
         'fetch_max_wait_ms': 500,

test/test_consumer_group.py

@@ -54,12 +54,14 @@ def test_group(kafka_broker, topic):
     stop = {}
     threads = {}
     messages = collections.defaultdict(list)
+    group_id = 'test-group-' + random_string(6)
     def consumer_thread(i):
         assert i not in consumers
         assert i not in stop
         stop[i] = threading.Event()
         consumers[i] = KafkaConsumer(topic,
                                      bootstrap_servers=connect_str,
+                                     group_id=group_id,
                                      heartbeat_interval_ms=500)
         while not stop[i].is_set():
             for tp, records in six.itervalues(consumers[i].poll(100)):