Improve metadata protocol handling

  - add MetadataRequest and MetadataResponse namedtuples
  - add TopicMetadata namedtuple
  - add error codes to Topic and Partition Metadata
  - add KafkaClient.send_metadata_request() method
  - KafkaProtocol.decode_metadata_response changed
    to return a MetadataResponse object
    so that it is consistent with server api: [broker_list, topic_list]

2 files changed, 123 insertions, 109 deletions

diff --git a/test/test_client.py b/test/test_client.py
index 32a2256..58254fc 100644
--- a/test/test_client.py
+++ b/test/test_client.py
@@ -1,10 +1,11 @@
 import unittest2
 
-from mock import MagicMock, patch
+from mock import ANY, MagicMock, patch
 
 from kafka import KafkaClient
 from kafka.common import (
-    ProduceRequest, BrokerMetadata, PartitionMetadata,
+    ProduceRequest, MetadataResponse,
+    BrokerMetadata, TopicMetadata, PartitionMetadata,
     TopicAndPartition, KafkaUnavailableError,
     LeaderUnavailableError, PartitionUnavailableError
 )
@@ -56,10 +57,12 @@ class TestKafkaClient(unittest2.TestCase):
                 client = KafkaClient(hosts=['kafka01:9092', 'kafka02:9092'])
 
                 with self.assertRaises(KafkaUnavailableError):
-                    client._send_broker_unaware_request(1, 'fake request')
+                    client._send_broker_unaware_request(payloads=['fake request'],
+                                                        encoder_fn=MagicMock(return_value='fake encoded message'),
+                                                        decoder_fn=lambda x: x)
 
                 for key, conn in mocked_conns.iteritems():
-                    conn.send.assert_called_with(1, 'fake request')
+                    conn.send.assert_called_with(ANY, 'fake encoded message')
 
     def test_send_broker_unaware_request(self):
         'Tests that call works when at least one of the host is available'
@@ -80,12 +83,15 @@ class TestKafkaClient(unittest2.TestCase):
         # patch to avoid making requests before we want it
         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')
+                with patch.object(KafkaClient, '_next_id', return_value=1):
+                    client = KafkaClient(hosts='kafka01:9092,kafka02:9092')
 
-                resp = client._send_broker_unaware_request(1, 'fake request')
+                    resp = client._send_broker_unaware_request(payloads=['fake request'],
+                                                               encoder_fn=MagicMock(),
+                                                               decoder_fn=lambda x: x)
 
-                self.assertEqual('valid response', resp)
-                mocked_conns[('kafka02', 9092)].recv.assert_called_with(1)
+                    self.assertEqual('valid response', resp)
+                    mocked_conns[('kafka02', 9092)].recv.assert_called_with(1)
 
     @patch('kafka.client.KafkaConnection')
     @patch('kafka.client.KafkaProtocol')
@@ -94,25 +100,27 @@ class TestKafkaClient(unittest2.TestCase):
 
         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)
+        brokers = [
+            BrokerMetadata(0, 'broker_1', 4567),
+            BrokerMetadata(1, 'broker_2', 5678)
+        ]
+
+        topics = [
+            TopicMetadata('topic_1', 0, [
+                PartitionMetadata('topic_1', 0, 1, [1, 2], [1, 2], 0)
+            ]),
+            TopicMetadata('topic_noleader', 0, [
+                PartitionMetadata('topic_noleader', 0, -1, [], [], 0),
+                PartitionMetadata('topic_noleader', 1, -1, [], [], 0)
+            ]),
+            TopicMetadata('topic_no_partitions', 0, []),
+            TopicMetadata('topic_3', 0, [
+                PartitionMetadata('topic_3', 0, 0, [0, 1], [0, 1], 0),
+                PartitionMetadata('topic_3', 1, 1, [1, 0], [1, 0], 0),
+                PartitionMetadata('topic_3', 2, 0, [0, 1], [0, 1], 0)
+            ])
+        ]
+        protocol.decode_metadata_response.return_value = MetadataResponse(brokers, topics)
 
         # client loads metadata at init
         client = KafkaClient(hosts=['broker_1:4567'])
@@ -132,30 +140,35 @@ class TestKafkaClient(unittest2.TestCase):
 
         conn.recv.return_value = 'response'  # anything but None
 
-        brokers = {}
-        brokers[0] = BrokerMetadata(0, 'broker_1', 4567)
-        brokers[1] = BrokerMetadata(1, 'broker_2', 5678)
+        brokers = [
+            BrokerMetadata(0, 'broker_1', 4567),
+            BrokerMetadata(1, 'broker_2', 5678)
+        ]
 
-        topics = {'topic_no_partitions': {}}
-        protocol.decode_metadata_response.return_value = (brokers, topics)
+        topics = [
+            TopicMetadata('topic_no_partitions', 0, [])
+        ]
+        protocol.decode_metadata_response.return_value = MetadataResponse(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)
+        topics = [
+            TopicMetadata('topic_one_partition', 0, [
+                PartitionMetadata('topic_no_partition', 0, 0, [0, 1], [0, 1], 0)
+            ])
+        ]
+        protocol.decode_metadata_response.return_value = MetadataResponse(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)
+        leader = client._get_leader_for_partition('topic_one_partition', 0)
 
         self.assertEqual(brokers[0], leader)
         self.assertDictEqual({
-            TopicAndPartition('topic_no_partitions', 0): brokers[0]},
+            TopicAndPartition('topic_one_partition', 0): brokers[0]},
             client.topics_to_brokers)
 
     @patch('kafka.client.KafkaConnection')
@@ -165,12 +178,15 @@ class TestKafkaClient(unittest2.TestCase):
 
         conn.recv.return_value = 'response'  # anything but None
 
-        brokers = {}
-        brokers[0] = BrokerMetadata(0, 'broker_1', 4567)
-        brokers[1] = BrokerMetadata(1, 'broker_2', 5678)
+        brokers = [
+            BrokerMetadata(0, 'broker_1', 4567),
+            BrokerMetadata(1, 'broker_2', 5678)
+        ]
 
-        topics = {'topic_no_partitions': {}}
-        protocol.decode_metadata_response.return_value = (brokers, topics)
+        topics = [
+            TopicMetadata('topic_no_partitions', 0, [])
+        ]
+        protocol.decode_metadata_response.return_value = MetadataResponse(brokers, topics)
 
         client = KafkaClient(hosts=['broker_1:4567'])
 
@@ -186,16 +202,18 @@ class TestKafkaClient(unittest2.TestCase):
 
         conn.recv.return_value = 'response'  # anything but None
 
-        brokers = {}
-        brokers[0] = BrokerMetadata(0, 'broker_1', 4567)
-        brokers[1] = BrokerMetadata(1, 'broker_2', 5678)
+        brokers = [
+            BrokerMetadata(0, 'broker_1', 4567),
+            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)
+        topics = [
+            TopicMetadata('topic_noleader', 0, [
+                PartitionMetadata('topic_noleader', 0, -1, [], [], 0),
+                PartitionMetadata('topic_noleader', 1, -1, [], [], 0)
+            ]),
+        ]
+        protocol.decode_metadata_response.return_value = MetadataResponse(brokers, topics)
 
         client = KafkaClient(hosts=['broker_1:4567'])
         self.assertDictEqual(
@@ -207,31 +225,35 @@ class TestKafkaClient(unittest2.TestCase):
         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)
+        topics = [
+            TopicMetadata('topic_noleader', 0, [
+                PartitionMetadata('topic_noleader', 0, 0, [0, 1], [0, 1], 0),
+                PartitionMetadata('topic_noleader', 1, 1, [1, 0], [1, 0], 0)
+            ]),
+        ]
+        protocol.decode_metadata_response.return_value = MetadataResponse(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"
+        "Send producer request raises LeaderNotAvailableError 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)
+        brokers = [
+            BrokerMetadata(0, 'broker_1', 4567),
+            BrokerMetadata(1, 'broker_2', 5678)
+        ]
+
+        topics = [
+            TopicMetadata('topic_noleader', 0, [
+                PartitionMetadata('topic_noleader', 0, -1, [], [], 0),
+                PartitionMetadata('topic_noleader', 1, -1, [], [], 0)
+            ]),
+        ]
+        protocol.decode_metadata_response.return_value = MetadataResponse(brokers, topics)
 
         client = KafkaClient(hosts=['broker_1:4567'])
 
diff --git a/test/test_protocol.py b/test/test_protocol.py
index 2089f48..a92d20e 100644
--- a/test/test_protocol.py
+++ b/test/test_protocol.py
@@ -11,10 +11,10 @@ from kafka.common import (
     OffsetRequest, OffsetCommitRequest, OffsetFetchRequest,
     OffsetResponse, OffsetCommitResponse, OffsetFetchResponse,
     ProduceRequest, FetchRequest, Message, ChecksumError,
-    ConsumerFetchSizeTooSmall, ProduceResponse, FetchResponse, OffsetAndMessage,
-    BrokerMetadata, PartitionMetadata, TopicAndPartition, KafkaUnavailableError,
-    ProtocolError, LeaderUnavailableError, PartitionUnavailableError,
-    UnsupportedCodecError
+    ProduceResponse, FetchResponse, OffsetAndMessage,
+    BrokerMetadata, TopicMetadata, PartitionMetadata, TopicAndPartition,
+    KafkaUnavailableError, PartitionUnavailableError,
+    UnsupportedCodecError, ConsumerFetchSizeTooSmall, ProtocolError,
 )
 from kafka.codec import (
     has_snappy, gzip_encode, gzip_decode,
@@ -454,21 +454,22 @@ class TestProtocol(unittest2.TestCase):
 
         self.assertEqual(encoded, expected)
 
-    def _create_encoded_metadata_response(self, broker_data, topic_data,
-                                          topic_errors, partition_errors):
-        encoded = struct.pack('>ii', 3, len(broker_data))
-        for node_id, broker in broker_data.iteritems():
-            encoded += struct.pack('>ih%dsi' % len(broker.host), node_id,
+    def _create_encoded_metadata_response(self, brokers, topics):
+        encoded = struct.pack('>ii', 3, len(brokers))
+        for broker in brokers:
+            encoded += struct.pack('>ih%dsi' % len(broker.host), broker.nodeId,
                                    len(broker.host), broker.host, broker.port)
 
-        encoded += struct.pack('>i', len(topic_data))
-        for topic, partitions in topic_data.iteritems():
-            encoded += struct.pack('>hh%dsi' % len(topic), topic_errors[topic],
-                                   len(topic), topic, len(partitions))
-            for partition, metadata in partitions.iteritems():
+        encoded += struct.pack('>i', len(topics))
+        for topic in topics:
+            encoded += struct.pack('>hh%dsi' % len(topic.topic),
+                                   topic.error, len(topic.topic),
+                                   topic.topic, len(topic.partitions))
+            for metadata in topic.partitions:
                 encoded += struct.pack('>hiii',
-                                       partition_errors[(topic, partition)],
-                                       partition, metadata.leader,
+                                       metadata.error,
+                                       metadata.partition,
+                                       metadata.leader,
                                        len(metadata.replicas))
                 if len(metadata.replicas) > 0:
                     encoded += struct.pack('>%di' % len(metadata.replicas),
@@ -478,35 +479,26 @@ class TestProtocol(unittest2.TestCase):
                 if len(metadata.isr) > 0:
                     encoded += struct.pack('>%di' % len(metadata.isr),
                                            *metadata.isr)
-
         return encoded
 
     def test_decode_metadata_response(self):
-        node_brokers = {
-            0: BrokerMetadata(0, "brokers1.kafka.rdio.com", 1000),
-            1: BrokerMetadata(1, "brokers1.kafka.rdio.com", 1001),
-            3: BrokerMetadata(3, "brokers2.kafka.rdio.com", 1000)
-        }
-
-        topic_partitions = {
-            "topic1": {
-                0: PartitionMetadata("topic1", 0, 1, (0, 2), (2,)),
-                1: PartitionMetadata("topic1", 1, 3, (0, 1), (0, 1))
-            },
-            "topic2": {
-                0: PartitionMetadata("topic2", 0, 0, (), ())
-            }
-        }
-        topic_errors = {"topic1": 0, "topic2": 1}
-        partition_errors = {
-            ("topic1", 0): 0,
-            ("topic1", 1): 1,
-            ("topic2", 0): 0
-        }
+        node_brokers = [
+            BrokerMetadata(0, "brokers1.kafka.rdio.com", 1000),
+            BrokerMetadata(1, "brokers1.kafka.rdio.com", 1001),
+            BrokerMetadata(3, "brokers2.kafka.rdio.com", 1000)
+        ]
+
+        topic_partitions = [
+            TopicMetadata("topic1", 0, [
+                PartitionMetadata("topic1", 0, 1, (0, 2), (2,), 0),
+                PartitionMetadata("topic1", 1, 3, (0, 1), (0, 1), 1)
+            ]),
+            TopicMetadata("topic2", 1, [
+                PartitionMetadata("topic2", 0, 0, (), (), 0),
+            ]),
+        ]
         encoded = self._create_encoded_metadata_response(node_brokers,
-                                                         topic_partitions,
-                                                         topic_errors,
-                                                         partition_errors)
+                                                         topic_partitions)
         decoded = KafkaProtocol.decode_metadata_response(encoded)
         self.assertEqual(decoded, (node_brokers, topic_partitions))