openstack/deb-python-kafka
Code Issues Proposed changes

Refactor internal metadata dicts in KafkaClient

Browse Source 
- use helper methods not direct access
 - add get_partition_ids_for_topic
 - check for topic and partition errors during load_metadata_for_topics
 - raise LeaderNotAvailableError when topic is being auto-created
   or UnknownTopicOrPartitionError if auto-creation off
This commit is contained in:
Dana Powers
2014-09-01 02:29:43 -07:00
parent bebe7b6638
commit 3bfe593e2f
4 changed files with 69 additions and 33 deletions
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76
kafka/client.py
View File

@@ -36,8 +36,9 @@ class KafkaClient(object):
# create connections only when we need them
self.conns = {}
self.brokers = {} # broker_id -> BrokerMetadata
self.topics_to_brokers = {} # topic_id -> broker_id
self.topic_partitions = {} # topic_id -> [0, 1, 2, ...]
self.topics_to_brokers = {} # TopicAndPartition -> BrokerMetadata
self.topic_partitions = {} # topic -> partition -> PartitionMetadata
self.load_metadata_for_topics() # bootstrap with all metadata
@@ -235,50 +236,85 @@ class KafkaClient(object):
self.topic_partitions.clear()
def has_metadata_for_topic(self, topic):
return topic in self.topic_partitions
return (
topic in self.topic_partitions
and len(self.topic_partitions[topic]) > 0
)
def get_partition_ids_for_topic(self, topic):
if topic not in self.topic_partitions:
return None
return self.topic_partitions[topic].keys()
def ensure_topic_exists(self, topic, timeout = 30):
start_time = time.time()
self.load_metadata_for_topics(topic)
while not self.has_metadata_for_topic(topic):
if time.time() > start_time + timeout:
raise KafkaTimeoutError("Unable to create topic {0}".format(topic))
self.load_metadata_for_topics(topic)
try:
self.load_metadata_for_topics(topic)
except LeaderNotAvailableError:
pass
time.sleep(.5)
def load_metadata_for_topics(self, *topics):
"""
Discover brokers and metadata for a set of topics. This function is called
lazily whenever metadata is unavailable.
"""
If broker does not auto-create topics, expect
UnknownTopicOrPartitionError for new topics
If broker auto-creates topics, expect
LeaderNotAvailableError for new topics
until partitions have been initialized.
Retry.
"""
resp = self.send_metadata_request(topics)
brokers = dict([(broker.nodeId, broker) for broker in resp.brokers])
topics = dict([(t.topic, dict([(p.partition, p) for p in t.partitions]) ) for t in resp.topics])
log.debug("Broker metadata: %s", resp.brokers)
log.debug("Topic metadata: %s", resp.topics)
log.debug("Broker metadata: %s", brokers)
log.debug("Topic metadata: %s", topics)
self.brokers = dict([(broker.nodeId, broker)
for broker in resp.brokers])
self.brokers = brokers
for topic_metadata in resp.topics:
topic = topic_metadata.topic
partitions = topic_metadata.partitions
for topic, partitions in topics.items():
self.reset_topic_metadata(topic)
if not partitions:
log.warning('No partitions for %s', topic)
continue
# Errors expected for new topics
# 3 if topic doesn't exist, or 5 if server is auto-creating
kafka.common.check_error(topic_metadata)
self.topic_partitions[topic] = []
for partition, meta in partitions.items():
self.topic_partitions[topic].append(partition)
self.topic_partitions[topic] = {}
for partition_metadata in partitions:
partition = partition_metadata.partition
leader = partition_metadata.leader
self.topic_partitions[topic][partition] = partition_metadata
# Populate topics_to_brokers dict
topic_part = TopicAndPartition(topic, partition)
if meta.leader == -1:
# If No Leader, topics_to_brokers topic_partition -> None
if leader == -1:
log.warning('No leader for topic %s partition %s', topic, partition)
self.topics_to_brokers[topic_part] = None
# If Known Broker, topic_partition -> BrokerMetadata
elif leader in self.brokers:
self.topics_to_brokers[topic_part] = self.brokers[leader]
# If Unknown Broker, fake BrokerMetadata so we dont lose the id
# (not sure how this could happen. server could be in bad state)
else:
self.topics_to_brokers[topic_part] = brokers[meta.leader]
self.topics_to_brokers[topic_part] = BrokerMetadata(
leader, None, None
)
def send_metadata_request(self, payloads=[], fail_on_error=True,
callback=None):

4
kafka/consumer.py
View File

@@ -82,7 +82,7 @@ class Consumer(object):
self.offsets = {}
if not partitions:
partitions = self.client.topic_partitions[topic]
partitions = self.client.get_partition_ids_for_topic(topic)
else:
assert all(isinstance(x, numbers.Integral) for x in partitions)
@@ -108,7 +108,7 @@ class Consumer(object):
def fetch_last_known_offsets(self, partitions=None):
if not partitions:
partitions = self.client.topic_partitions[self.topic]
partitions = self.client.get_partition_ids_for_topic(self.topic)
def get_or_init_offset_callback(resp):
try:

19
kafka/producer.py
View File

@@ -241,16 +241,14 @@ class SimpleProducer(Producer):
def _next_partition(self, topic):
if topic not in self.partition_cycles:
if topic not in self.client.topic_partitions:
if not self.client.has_metadata_for_topic(topic):
self.client.load_metadata_for_topics(topic)
try:
self.partition_cycles[topic] = cycle(self.client.topic_partitions[topic])
except KeyError:
raise UnknownTopicOrPartitionError(topic)
self.partition_cycles[topic] = cycle(self.client.get_partition_ids_for_topic(topic))
# Randomize the initial partition that is returned
if self.random_start:
num_partitions = len(self.client.topic_partitions[topic])
num_partitions = len(self.client.get_partition_ids_for_topic(topic))
for _ in xrange(random.randint(0, num_partitions-1)):
self.partition_cycles[topic].next()
@@ -299,12 +297,13 @@ class KeyedProducer(Producer):
def _next_partition(self, topic, key):
if topic not in self.partitioners:
if topic not in self.client.topic_partitions:
if not self.client.has_metadata_for_topic(topic):
self.client.load_metadata_for_topics(topic)
self.partitioners[topic] = \
self.partitioner_class(self.client.topic_partitions[topic])
self.partitioners[topic] = self.partitioner_class(self.client.get_partition_ids_for_topic(topic))
partitioner = self.partitioners[topic]
return partitioner.partition(key, self.client.topic_partitions[topic])
return partitioner.partition(key, self.client.get_partition_ids_for_topic(topic))
def send(self, topic, key, msg):
partition = self._next_partition(topic, key)

3
test/test_producer_integration.py
View File

@@ -148,7 +148,8 @@ class TestKafkaProducerIntegration(KafkaIntegrationTestCase):
producer = SimpleProducer(self.client)
# At first it doesn't exist
with self.assertRaises(UnknownTopicOrPartitionError):
with self.assertRaises((UnknownTopicOrPartitionError,
LeaderNotAvailableError)):
resp = producer.send_messages(new_topic, self.msg("one"))
@kafka_versions("all")