Merge pull request dpkp#109 from mrtheb/develop

TopicAndPartition fix when partition has no leader = -1

kafka/client.py

@@ -8,7 +8,8 @@
 from kafka.common import (ErrorMapping, TopicAndPartition,
                           ConnectionError, FailedPayloadsError,
                           BrokerResponseError, PartitionUnavailableError,
-                          KafkaUnavailableError, KafkaRequestError)
+                          LeaderUnavailableError,
+                          KafkaUnavailableError)
 
 from kafka.conn import collect_hosts, KafkaConnection, DEFAULT_SOCKET_TIMEOUT_SECONDS
 from kafka.protocol import KafkaProtocol
@@ -62,12 +63,22 @@ def _get_conn_for_broker(self, broker):
         return self._get_conn(broker.host, broker.port)
 
     def _get_leader_for_partition(self, topic, partition):
+        """
+        Returns the leader for a partition or None if the partition exists
+        but has no leader.
+
+        PartitionUnavailableError will be raised if the topic or partition
+        is not part of the metadata.
+        """
+
         key = TopicAndPartition(topic, partition)
-        if key not in self.topics_to_brokers:
+        # reload metadata whether the partition is not available
+        # or has no leader (broker is None)
+        if self.topics_to_brokers.get(key) is None:
             self.load_metadata_for_topics(topic)
 
         if key not in self.topics_to_brokers:
-            raise KafkaRequestError("Partition does not exist: %s" % str(key))
+            raise PartitionUnavailableError("%s not available" % str(key))
 
         return self.topics_to_brokers[key]
 
@@ -124,8 +135,11 @@ def _send_broker_aware_request(self, payloads, encoder_fn, decoder_fn):
         for payload in payloads:
             leader = self._get_leader_for_partition(payload.topic,
                                                     payload.partition)
-            if leader == -1:
-                raise PartitionUnavailableError("Leader is unassigned for %s-%s" % payload.topic, payload.partition)
+            if leader is None:
+                raise LeaderUnavailableError(
+                    "Leader not available for topic %s partition %s" %
+                    (payload.topic, payload.partition))
+
             payloads_by_broker[leader].append(payload)
             original_keys.append((payload.topic, payload.partition))
 
@@ -250,13 +264,18 @@ def load_metadata_for_topics(self, *topics):
             self.reset_topic_metadata(topic)
 
             if not partitions:
+                log.warning('No partitions for %s', topic)
                 continue
 
             self.topic_partitions[topic] = []
             for partition, meta in partitions.items():
-                topic_part = TopicAndPartition(topic, partition)
-                self.topics_to_brokers[topic_part] = brokers[meta.leader]
                 self.topic_partitions[topic].append(partition)
+                topic_part = TopicAndPartition(topic, partition)
+                if meta.leader == -1:
+                    log.warning('No leader for topic %s partition %s', topic, partition)
+                    self.topics_to_brokers[topic_part] = None
+                else:
+                    self.topics_to_brokers[topic_part] = brokers[meta.leader]
 
     def send_produce_request(self, payloads=[], acks=1, timeout=1000,
                              fail_on_error=True, callback=None):

kafka/common.py

@@ -74,15 +74,15 @@ class KafkaError(RuntimeError):
     pass
 
 
-class KafkaRequestError(KafkaError):
+class KafkaUnavailableError(KafkaError):
     pass
 
 
-class KafkaUnavailableError(KafkaError):
+class BrokerResponseError(KafkaError):
     pass
 
 
-class BrokerResponseError(KafkaError):
+class LeaderUnavailableError(KafkaError):
     pass
 
 

setup.py

@@ -23,7 +23,7 @@ def run(self):
     version="0.9.0",
 
     install_requires=["distribute"],
-    tests_require=["tox"],
+    tests_require=["tox", "mock"],
     cmdclass={"test": Tox},
 
     packages=["kafka"],

test/test_unit.py

@@ -5,14 +5,14 @@
 
 from mock import MagicMock, patch
 
-
 from kafka import KafkaClient
 from kafka.common import (
     ProduceRequest, FetchRequest, Message, ChecksumError,
     ConsumerFetchSizeTooSmall, ProduceResponse, FetchResponse,
-    OffsetAndMessage, BrokerMetadata, PartitionMetadata
+    OffsetAndMessage, BrokerMetadata, PartitionMetadata,
+    TopicAndPartition, KafkaUnavailableError, 
+    LeaderUnavailableError, PartitionUnavailableError
 )
-from kafka.common import KafkaUnavailableError
 from kafka.codec import (
     has_gzip, has_snappy, gzip_encode, gzip_decode,
     snappy_encode, snappy_decode
@@ -410,6 +410,7 @@ def test_encode_offset_request(self):
     def test_decode_offset_response(self):
         pass
 
+
     @unittest.skip("Not Implemented")
     def test_encode_offset_commit_request(self):
         pass
@@ -474,18 +475,17 @@ def mock_get_conn(host, port):
             return mocked_conns[(host, port)]
 
         # patch to avoid making requests before we want it
-        with patch.object(KafkaClient, 'load_metadata_for_topics'), \
-                patch.object(KafkaClient, '_get_conn', side_effect=mock_get_conn):
-
-            client = KafkaClient(hosts=['kafka01:9092', 'kafka02:9092'])
+        with patch.object(KafkaClient, 'load_metadata_for_topics'):
+            with patch.object(KafkaClient, '_get_conn', side_effect=mock_get_conn):
+                client = KafkaClient(hosts=['kafka01:9092', 'kafka02:9092'])
 
-            self.assertRaises(
-                KafkaUnavailableError,
-                client._send_broker_unaware_request,
-                1, 'fake request')
+                self.assertRaises(
+                    KafkaUnavailableError,
+                    client._send_broker_unaware_request,
+                    1, 'fake request')
 
-            for key, conn in mocked_conns.iteritems():
-                conn.send.assert_called_with(1, 'fake request')
+                for key, conn in mocked_conns.iteritems():
+                    conn.send.assert_called_with(1, 'fake request')
 
     def test_send_broker_unaware_request(self):
         'Tests that call works when at least one of the host is available'
@@ -504,16 +504,171 @@ def mock_get_conn(host, port):
             return mocked_conns[(host, port)]
 
         # patch to avoid making requests before we want it
-        with patch.object(KafkaClient, 'load_metadata_for_topics'), \
-                patch.object(KafkaClient, '_get_conn', side_effect=mock_get_conn):
+        with patch.object(KafkaClient, 'load_metadata_for_topics'):
+            with patch.object(KafkaClient, '_get_conn', side_effect=mock_get_conn):
+                client = KafkaClient(hosts='kafka01:9092,kafka02:9092')
+
+                resp = client._send_broker_unaware_request(1, 'fake request')
+
+                self.assertEqual('valid response', resp)
+                mocked_conns[('kafka02', 9092)].recv.assert_called_with(1)
+
+    @patch('kafka.client.KafkaConnection')
+    @patch('kafka.client.KafkaProtocol')
+    def test_load_metadata(self, protocol, conn):
+        "Load metadata for all topics"
+
+        conn.recv.return_value = 'response'  # anything but None
+
+        brokers = {}
+        brokers[0] = BrokerMetadata(1, 'broker_1', 4567)
+        brokers[1] = BrokerMetadata(2, 'broker_2', 5678)
+
+        topics = {}
+        topics['topic_1'] = {
+            0: PartitionMetadata('topic_1', 0, 1, [1, 2], [1, 2])
+        }
+        topics['topic_noleader'] = {
+            0: PartitionMetadata('topic_noleader', 0, -1, [], []),
+            1: PartitionMetadata('topic_noleader', 1, -1, [], [])
+        }
+        topics['topic_no_partitions'] = {}
+        topics['topic_3'] = {
+            0: PartitionMetadata('topic_3', 0, 0, [0, 1], [0, 1]),
+            1: PartitionMetadata('topic_3', 1, 1, [1, 0], [1, 0]),
+            2: PartitionMetadata('topic_3', 2, 0, [0, 1], [0, 1])
+        }
+        protocol.decode_metadata_response.return_value = (brokers, topics)
+
+        # client loads metadata at init
+        client = KafkaClient(hosts=['broker_1:4567'])
+        self.assertDictEqual({
+            TopicAndPartition('topic_1', 0): brokers[1],
+            TopicAndPartition('topic_noleader', 0): None,
+            TopicAndPartition('topic_noleader', 1): None,
+            TopicAndPartition('topic_3', 0): brokers[0],
+            TopicAndPartition('topic_3', 1): brokers[1],
+            TopicAndPartition('topic_3', 2): brokers[0]},
+            client.topics_to_brokers)
+
+    @patch('kafka.client.KafkaConnection')
+    @patch('kafka.client.KafkaProtocol')
+    def test_get_leader_for_partitions_reloads_metadata(self, protocol, conn):
+        "Get leader for partitions reload metadata if it is not available"
+
+        conn.recv.return_value = 'response'  # anything but None
+
+        brokers = {}
+        brokers[0] = BrokerMetadata(0, 'broker_1', 4567)
+        brokers[1] = BrokerMetadata(1, 'broker_2', 5678)
+
+        topics = {'topic_no_partitions': {}}
+        protocol.decode_metadata_response.return_value = (brokers, topics)
+
+        client = KafkaClient(hosts=['broker_1:4567'])
+
+        # topic metadata is loaded but empty
+        self.assertDictEqual({}, client.topics_to_brokers)
+
+        topics['topic_no_partitions'] = {
+            0: PartitionMetadata('topic_no_partitions', 0, 0, [0, 1], [0, 1])
+        }
+        protocol.decode_metadata_response.return_value = (brokers, topics)
+
+        # calling _get_leader_for_partition (from any broker aware request)
+        # will try loading metadata again for the same topic
+        leader = client._get_leader_for_partition('topic_no_partitions', 0)
+
+        self.assertEqual(brokers[0], leader)
+        self.assertDictEqual({
+            TopicAndPartition('topic_no_partitions', 0): brokers[0]},
+            client.topics_to_brokers)
+
+    @patch('kafka.client.KafkaConnection')
+    @patch('kafka.client.KafkaProtocol')
+    def test_get_leader_for_unassigned_partitions(self, protocol, conn):
+        "Get leader raises if no partitions is defined for a topic"
+
+        conn.recv.return_value = 'response'  # anything but None
+
+        brokers = {}
+        brokers[0] = BrokerMetadata(0, 'broker_1', 4567)
+        brokers[1] = BrokerMetadata(1, 'broker_2', 5678)
+
+        topics = {'topic_no_partitions': {}}
+        protocol.decode_metadata_response.return_value = (brokers, topics)
+
+        client = KafkaClient(hosts=['broker_1:4567'])
+
+        self.assertDictEqual({}, client.topics_to_brokers)
+        self.assertRaises(
+            PartitionUnavailableError,
+            client._get_leader_for_partition,
+            'topic_no_partitions', 0)
+
+    @patch('kafka.client.KafkaConnection')
+    @patch('kafka.client.KafkaProtocol')
+    def test_get_leader_returns_none_when_noleader(self, protocol, conn):
+        "Getting leader for partitions returns None when the partiion has no leader"
+
+        conn.recv.return_value = 'response'  # anything but None
 
-            client = KafkaClient(hosts='kafka01:9092,kafka02:9092')
+        brokers = {}
+        brokers[0] = BrokerMetadata(0, 'broker_1', 4567)
+        brokers[1] = BrokerMetadata(1, 'broker_2', 5678)
+
+        topics = {}
+        topics['topic_noleader'] = {
+            0: PartitionMetadata('topic_noleader', 0, -1, [], []),
+            1: PartitionMetadata('topic_noleader', 1, -1, [], [])
+        }
+        protocol.decode_metadata_response.return_value = (brokers, topics)
+
+        client = KafkaClient(hosts=['broker_1:4567'])
+        self.assertDictEqual(
+            {
+                TopicAndPartition('topic_noleader', 0): None,
+                TopicAndPartition('topic_noleader', 1): None
+            },
+            client.topics_to_brokers)
+        self.assertIsNone(client._get_leader_for_partition('topic_noleader', 0))
+        self.assertIsNone(client._get_leader_for_partition('topic_noleader', 1))
+
+        topics['topic_noleader'] = {
+            0: PartitionMetadata('topic_noleader', 0, 0, [0, 1], [0, 1]),
+            1: PartitionMetadata('topic_noleader', 1, 1, [1, 0], [1, 0])
+        }
+        protocol.decode_metadata_response.return_value = (brokers, topics)
+        self.assertEqual(brokers[0], client._get_leader_for_partition('topic_noleader', 0))
+        self.assertEqual(brokers[1], client._get_leader_for_partition('topic_noleader', 1))
+
+    @patch('kafka.client.KafkaConnection')
+    @patch('kafka.client.KafkaProtocol')
+    def test_send_produce_request_raises_when_noleader(self, protocol, conn):
+        "Send producer request raises LeaderUnavailableError if leader is not available"
+
+        conn.recv.return_value = 'response'  # anything but None
+
+        brokers = {}
+        brokers[0] = BrokerMetadata(0, 'broker_1', 4567)
+        brokers[1] = BrokerMetadata(1, 'broker_2', 5678)
+
+        topics = {}
+        topics['topic_noleader'] = {
+            0: PartitionMetadata('topic_noleader', 0, -1, [], []),
+            1: PartitionMetadata('topic_noleader', 1, -1, [], [])
+        }
+        protocol.decode_metadata_response.return_value = (brokers, topics)
 
-            resp = client._send_broker_unaware_request(1, 'fake request')
+        client = KafkaClient(hosts=['broker_1:4567'])
 
-            self.assertEqual('valid response', resp)
-            mocked_conns[('kafka02', 9092)].recv.assert_called_with(1)
+        requests = [ProduceRequest(
+            "topic_noleader", 0,
+            [create_message("a"), create_message("b")])]
 
+        self.assertRaises(
+            LeaderUnavailableError,
+            client.send_produce_request, requests)
 
 if __name__ == '__main__':
     unittest.main()

tox.ini

@@ -1,7 +1,9 @@
 [tox]
 envlist = py26, py27
 [testenv]
-deps = pytest
+deps =
+    pytest
+    mock
 commands = py.test --basetemp={envtmpdir} []
 setenv =
     PROJECT_ROOT = {toxinidir}