Support optional partitions kwarg in MultiProcessConsumer

Author: Dana Powers

kafka/consumer/multiprocess.py

@@ -98,6 +98,7 @@ class MultiProcessConsumer(Consumer):
         topic: the topic to consume
 
     Keyword Arguments:
+        partitions: An optional list of partitions to consume the data from
         auto_commit: default True. Whether or not to auto commit the offsets
         auto_commit_every_n: default 100. How many messages to consume
             before a commit
@@ -114,16 +115,19 @@ class MultiProcessConsumer(Consumer):
     commit method on this class. A manual call to commit will also reset
     these triggers
     """
-    def __init__(self, client, group, topic, auto_commit=True,
+    def __init__(self, client, group, topic,
+                 partitions=None,
+                 auto_commit=True,
                  auto_commit_every_n=AUTO_COMMIT_MSG_COUNT,
                  auto_commit_every_t=AUTO_COMMIT_INTERVAL,
-                 num_procs=1, partitions_per_proc=0,
+                 num_procs=1,
+                 partitions_per_proc=0,
                  **simple_consumer_options):
 
         # Initiate the base consumer class
         super(MultiProcessConsumer, self).__init__(
             client, group, topic,
-            partitions=None,
+            partitions=partitions,
             auto_commit=auto_commit,
             auto_commit_every_n=auto_commit_every_n,
             auto_commit_every_t=auto_commit_every_t)

test/test_consumer.py

@@ -1,8 +1,8 @@
 
-from mock import MagicMock
+from mock import MagicMock, patch
 from . import unittest
 
-from kafka import SimpleConsumer, KafkaConsumer
+from kafka import SimpleConsumer, KafkaConsumer, MultiProcessConsumer
 from kafka.common import KafkaConfigurationError
 
 class TestKafkaConsumer(unittest.TestCase):
@@ -13,3 +13,12 @@ def test_non_integer_partitions(self):
     def test_broker_list_required(self):
         with self.assertRaises(KafkaConfigurationError):
             KafkaConsumer()
+
+class TestMultiProcessConsumer(unittest.TestCase):
+    def test_partition_list(self):
+        client = MagicMock()
+        partitions = (0,)
+        with patch.object(MultiProcessConsumer, 'fetch_last_known_offsets') as fetch_last_known_offsets:
+            consumer = MultiProcessConsumer(client, 'testing-group', 'testing-topic', partitions=partitions)
+            self.assertEqual(fetch_last_known_offsets.call_args[0], (partitions,) )
+        self.assertEqual(client.get_partition_ids_for_topic.call_count, 0) # pylint: disable=no-member