class Worker(object):
def __init__(self, topic, hosts=None, log_level=logging.WARNING):
hosts = hosts or "localhost:9092"
self.group = "kafque"
self.topic = "{}_{}".format(self.group, topic)
self.client = KafkaClient(hosts)
self.client.ensure_topic_exists(str(self.topic))
self.consumer = SimpleConsumer(
self.client, str(self.group), str(self.topic), auto_commit=False)
self.consumer.provide_partition_info()
self.consumer.fetch_last_known_offsets()
self.logger = setup_logger(__name__, level=log_level)
self.failed_queue = None
if self.topic != "{}_failed".format(self.group):
self.failed_queue = FailedQueue(
hosts=hosts, log_level=logging.ERROR)
def handle_signals(self):
def warm_shutdown(signum, frame):
# TODO: if worker is busy, defer cleanup to cold_shutdown
self.logger.debug("Got signal {}.".format(signum))
self.logger.warning("Warm shut down.")
raise SystemExit()
signal.signal(signal.SIGINT, warm_shutdown)
signal.signal(signal.SIGTERM, warm_shutdown)
def run(self):
self.logger.info("kafque worker started.")
self.handle_signals()
for partition, message in self.consumer:
self.logger.debug("Offset {}".format(message.offset))
job = json.loads(message.message.value)
callback = callback_from_string(job.pop("callback"))
try:
result = callback(*job["args"], **job["kwargs"])
self.logger.info(result)
self.consumer.commit()
except Exception as exc:
self.logger.error(exc, exc_info=True)
# TODO: set job as failed
if self.failed_queue:
self.failed_queue.enqueue(
callback, args=job["args"], kwargs=job["kwargs"])
self.consumer.commit()
class ZKConsumer(object):
zk_timeout = 30
jitter_seconds = 30
broker_prefix = '/brokers/ids'
def __init__(
self,
zk_hosts,
group,
topic,
nodes,
zk_handler=None,
logger=None,
identifier=None,
**consumer_kwargs):
"""Creates a Consumer that tracks state in ZooKeeper,
rebalancing partition ownership as registered consumers change.
NOTE: this class is intended for version 0.8.1 of Kafka, where offsets
are managed by Kafka but there is no rebalancing in the protocol.
"""
if logger is None:
logger = logging.getLogger('kafka.consumer.ZKConsumer')
self.logger = logger
self.identifier = identifier
if KafkaClient is None:
raise RuntimeError("Kafka support requires cs.eyrie to be installed with the Kafka extra: install_requires= ['cs.eyrie[Kafka]']")
self.zk_handler = zk_handler
self.zk_hosts = zk_hosts
self.broker_hosts = []
self.group = group
self.topic = topic
self.zk = None
self.nodes = nodes
self.client = None
self.consumer = None
self.consumer_kwargs = consumer_kwargs
# This will kick off a cascading sequence to initialize ourselves:
# 1. Connect to ZK and pull list of Kafka brokers
# 2. Register ourselves as a consumer in ZK
# 3. Rebalance partitions across all connected consumers
self.init_zk()
def zk_session_watch(self, state):
self.logger.debug('ZK transitioned to: %s', state)
if state == KazooState.SUSPENDED:
if self.consumer is not None:
self.logger.info('Stopping Kafka consumer')
self.consumer.stop()
self.consumer = None
# Lost connection to ZK; we can't call any methods that would
# try to contact it (i.e., we can't do self.zkp.finish() )
self.zkp = None
elif state == KazooState.CONNECTED:
self.logger.info('Restarting ZK partitioner')
self.zk.handler.spawn(self.init_zkp)
def _zkp_wait(self):
handler = self.zk.handler
while 1:
if self.zkp.failed:
self.logger.warning("Lost or unable to acquire partition")
self.stop()
elif self.zkp.release:
self.zkp.release_set()
elif self.zkp.acquired:
def group_change_proxy(event):
self.logger.warn('Connected consumers changed')
if self.zkp is None:
self.logger.info('Restarting ZK partitioner')
handler.spawn(self.init_zkp)
elif self.zkp is not None and self.zkp.failed:
self.logger.warning("Lost or unable to acquire partition")
self.stop()
else:
self.logger.info('Scheduling ZK partitioner set release')
rel_greenlet = handler.spawn(self.zkp.release_set)
self.logger.info('Scheduling group re-join')
rel_greenlet.link_value(lambda greenlet: self.zkp.join_group)
if not self.nodes:
self.logger.info('Partitioner aquired; setting child watch')
result = self.zk.get_children_async(self.zkp._group_path)
result.rawlink(group_change_proxy)
# Break out of while loop to begin consuming events
break
elif self.zkp.allocating:
self.zkp.wait_for_acquire()
def init_zkp(self):
if not hasattr(self, 'zkp') or self.zkp is None:
if self.nodes:
self.zkp = StaticZKPartitioner(
self.zk, self.group, self.topic, self.nodes,
partitions_changed_cb=self.init_consumer,
logger=self.logger, identifier=self.identifier)
else:
self.zkp = ZKPartitioner(
self.zk, self.group, self.topic,
time_boundary=self.jitter_seconds,
partitions_changed_cb=self.init_consumer,
logger=self.logger, identifier=self.identifier)
self._zkp_wait()
def init_zk(self):
# TODO: switch to async
# 1. implement kazoo.interfaces.IHandler in terms of Tornado's IOLoop
self.zk = KazooClient(hosts=self.zk_hosts, handler=self.zk_handler)
self.zk.start()
self.zk.add_listener(self.zk_session_watch)
@self.zk.ChildrenWatch(self.broker_prefix)
def broker_change_proxy(broker_ids):
self.onBrokerChange(broker_ids)
self.init_zkp()
def onBrokerChange(self, broker_ids):
self.broker_hosts = []
for b_id in broker_ids:
b_json, zstat = self.zk.get('/'.join([self.broker_prefix, b_id]))
b_data = json.loads(b_json)
self.broker_hosts.append('{}:{}'.format(b_data['host'],
b_data['port']))
my_partitions = []
if self.consumer is not None:
self.logger.warn('Brokers changed, stopping Kafka consumer.')
my_partitions = self.consumer.offsets.keys()
self.consumer.stop()
self.consumer = None
if self.client is not None:
self.logger.warn('Brokers changed, stopping Kafka client.')
self.client.close()
self.client = None
if my_partitions:
msg = 'Brokers changed, queuing restart of Kafka client / consumer.'
self.logger.warn(msg)
self.zk.handler.spawn(self.init_consumer, my_partitions)
def init_consumer(self, my_partitions):
if self.consumer is None:
self.logger.warn('Starting Kafka client')
self.client = KafkaClient(self.broker_hosts,
client_id=self.zkp._identifier)
else:
if self.consumer is None or \
sorted(my_partitions) != sorted(self.consumer.offsets.keys()):
self.logger.warn('Partitions changed, restarting Kafka consumer.')
self.consumer.stop()
else:
self.logger.info('Partitions unchanged, not restarting Kafka consumer.')
return
self.consumer = SimpleConsumer(self.client, self.group, self.topic,
partitions=my_partitions,
**self.consumer_kwargs)
self.consumer.provide_partition_info()
self.logger.info("Consumer connected to Kafka: %s", self.consumer.offsets)
def stop(self):
if self.consumer is not None:
self.logger.info('Stopping Kafka consumer')
self.consumer.stop()
self.consumer = None
if self.client is not None:
self.logger.info('Stopping Kafka client')
self.client.close()
self.client = None
if self.zk is not None:
self.logger.info('Stopping ZooKeeper client')
if self.zkp is not None and not self.zkp.failed:
self.zkp.finish()
self.zk.stop()
self.zkp = None
self.zk = None
def commit(self, partitions=None):
"""
Commit offsets for this consumer
partitions: list of partitions to commit, default is to commit
all of them
"""
if self.consumer is None:
return
self.logger.debug('Begin committing offsets for partitions: %s',
partitions if partitions else 'All')
self.consumer.commit(partitions)
self.logger.debug('End committing offsets for partitions: %s',
partitions if partitions else 'All')
def pending(self, partitions=None):
"""
Gets the pending message count
partitions: list of partitions to check for, default is to check all
"""
return self.consumer.pending(partitions)
def provide_partition_info(self):
"""
Indicates that partition info must be returned by the consumer
"""
self.consumer.provide_partition_info()
def seek(self, offset, whence):
"""
Alter the current offset in the consumer, similar to fseek
offset: how much to modify the offset
whence: where to modify it from
0 is relative to the earliest available offset (head)
1 is relative to the current offset
2 is relative to the latest known offset (tail)
"""
self.consumer.seek(offset, whence)
def get_messages(self, count=1, block=True, timeout=0.1):
"""
Fetch the specified number of messages
count: Indicates the maximum number of messages to be fetched
block: If True, the API will block till some messages are fetched.
timeout: If block is True, the function will block for the specified
time (in seconds) until count messages is fetched. If None,
it will block forever.
"""
if self.consumer is None:
return []
else:
try:
messages = self.consumer.get_messages(count, block, timeout)
if not messages and self.zkp.failed:
raise FailedPayloadsError
return messages
except FailedPayloadsError as err:
msg = 'Failed to retrieve payload, restarting consumer'
self.logger.exception(msg)
raise err
def get_message(self, block=True, timeout=0.1, get_partition_info=None):
return self.consumer.get_message(block, timeout, get_partition_info)
def _get_message(self, block=True, timeout=0.1, get_partition_info=None,
update_offset=True):
return self.consumer._get_message(block, timeout, get_partition_info,
update_offset)
def __iter__(self):
for msg in self.consumer:
yield msg
class ZKConsumer(object):
zk_timeout = 30
jitter_seconds = 30
broker_prefix = '/brokers/ids'
def __init__(self,
zk_hosts,
group,
topic,
nodes,
zk_handler=None,
logger=None,
identifier=None,
**consumer_kwargs):
"""Creates a Consumer that tracks state in ZooKeeper,
rebalancing partition ownership as registered consumers change.
NOTE: this class is intended for version 0.8.1 of Kafka, where offsets
are managed by Kafka but there is no rebalancing in the protocol.
"""
if logger is None:
logger = logging.getLogger('kafka.consumer.ZKConsumer')
self.logger = logger
self.identifier = identifier
if KafkaClient is None:
raise RuntimeError(
"Kafka support requires cs.eyrie to be installed with the Kafka extra: install_requires= ['cs.eyrie[Kafka]']"
)
self.zk_handler = zk_handler
self.zk_hosts = zk_hosts
self.broker_hosts = []
self.group = group
self.topic = topic
self.zk = None
self.nodes = nodes
self.client = None
self.consumer = None
self.consumer_kwargs = consumer_kwargs
# This will kick off a cascading sequence to initialize ourselves:
# 1. Connect to ZK and pull list of Kafka brokers
# 2. Register ourselves as a consumer in ZK
# 3. Rebalance partitions across all connected consumers
self.init_zk()
def zk_session_watch(self, state):
self.logger.debug('ZK transitioned to: %s', state)
if state == KazooState.SUSPENDED:
if self.consumer is not None:
self.logger.info('Stopping Kafka consumer')
self.consumer.stop()
self.consumer = None
# Lost connection to ZK; we can't call any methods that would
# try to contact it (i.e., we can't do self.zkp.finish() )
self.zkp = None
elif state == KazooState.CONNECTED:
self.logger.info('Restarting ZK partitioner')
self.zk.handler.spawn(self.init_zkp)
def _zkp_wait(self):
handler = self.zk.handler
while 1:
if self.zkp.failed:
self.logger.warning("Lost or unable to acquire partition")
self.stop()
elif self.zkp.release:
self.zkp.release_set()
elif self.zkp.acquired:
def group_change_proxy(event):
self.logger.warn('Connected consumers changed')
if self.zkp is None:
self.logger.info('Restarting ZK partitioner')
handler.spawn(self.init_zkp)
elif self.zkp is not None and self.zkp.failed:
self.logger.warning(
"Lost or unable to acquire partition")
self.stop()
else:
self.logger.info(
'Scheduling ZK partitioner set release')
rel_greenlet = handler.spawn(self.zkp.release_set)
self.logger.info('Scheduling group re-join')
rel_greenlet.link_value(
lambda greenlet: self.zkp.join_group)
if not self.nodes:
self.logger.info(
'Partitioner aquired; setting child watch')
result = self.zk.get_children_async(self.zkp._group_path)
result.rawlink(group_change_proxy)
# Break out of while loop to begin consuming events
break
elif self.zkp.allocating:
self.zkp.wait_for_acquire()
def init_zkp(self):
if not hasattr(self, 'zkp') or self.zkp is None:
if self.nodes:
self.zkp = StaticZKPartitioner(
self.zk,
self.group,
self.topic,
self.nodes,
partitions_changed_cb=self.init_consumer,
logger=self.logger,
identifier=self.identifier)
else:
self.zkp = ZKPartitioner(
self.zk,
self.group,
self.topic,
time_boundary=self.jitter_seconds,
partitions_changed_cb=self.init_consumer,
logger=self.logger,
identifier=self.identifier)
self._zkp_wait()
def init_zk(self):
# TODO: switch to async
# 1. implement kazoo.interfaces.IHandler in terms of Tornado's IOLoop
self.zk = KazooClient(hosts=self.zk_hosts, handler=self.zk_handler)
self.zk.start()
self.zk.add_listener(self.zk_session_watch)
@self.zk.ChildrenWatch(self.broker_prefix)
def broker_change_proxy(broker_ids):
self.onBrokerChange(broker_ids)
self.init_zkp()
def onBrokerChange(self, broker_ids):
self.broker_hosts = []
for b_id in broker_ids:
b_json, zstat = self.zk.get('/'.join([self.broker_prefix, b_id]))
b_data = json.loads(b_json)
self.broker_hosts.append('{}:{}'.format(b_data['host'],
b_data['port']))
my_partitions = []
if self.consumer is not None:
self.logger.warn('Brokers changed, stopping Kafka consumer.')
my_partitions = self.consumer.offsets.keys()
self.consumer.stop()
self.consumer = None
if self.client is not None:
self.logger.warn('Brokers changed, stopping Kafka client.')
self.client.close()
self.client = None
if my_partitions:
msg = 'Brokers changed, queuing restart of Kafka client / consumer.'
self.logger.warn(msg)
self.zk.handler.spawn(self.init_consumer, my_partitions)
def init_consumer(self, my_partitions):
if self.consumer is None:
self.logger.warn('Starting Kafka client')
self.client = KafkaClient(self.broker_hosts,
client_id=self.zkp._identifier)
else:
if self.consumer is None or \
sorted(my_partitions) != sorted(self.consumer.offsets.keys()):
self.logger.warn(
'Partitions changed, restarting Kafka consumer.')
self.consumer.stop()
else:
self.logger.info(
'Partitions unchanged, not restarting Kafka consumer.')
return
self.consumer = SimpleConsumer(self.client,
self.group,
self.topic,
partitions=my_partitions,
**self.consumer_kwargs)
self.consumer.provide_partition_info()
self.logger.info("Consumer connected to Kafka: %s",
self.consumer.offsets)
def stop(self):
if self.consumer is not None:
self.logger.info('Stopping Kafka consumer')
self.consumer.stop()
self.consumer = None
if self.client is not None:
self.logger.info('Stopping Kafka client')
self.client.close()
self.client = None
if self.zk is not None:
self.logger.info('Stopping ZooKeeper client')
if self.zkp is not None and not self.zkp.failed:
self.zkp.finish()
self.zk.stop()
self.zkp = None
self.zk = None
def commit(self, partitions=None):
"""
Commit offsets for this consumer
partitions: list of partitions to commit, default is to commit
all of them
"""
if self.consumer is None:
return
self.logger.debug('Begin committing offsets for partitions: %s',
partitions if partitions else 'All')
self.consumer.commit(partitions)
self.logger.debug('End committing offsets for partitions: %s',
partitions if partitions else 'All')
def pending(self, partitions=None):
"""
Gets the pending message count
partitions: list of partitions to check for, default is to check all
"""
return self.consumer.pending(partitions)
def provide_partition_info(self):
"""
Indicates that partition info must be returned by the consumer
"""
self.consumer.provide_partition_info()
def seek(self, offset, whence):
"""
Alter the current offset in the consumer, similar to fseek
offset: how much to modify the offset
whence: where to modify it from
0 is relative to the earliest available offset (head)
1 is relative to the current offset
2 is relative to the latest known offset (tail)
"""
self.consumer.seek(offset, whence)
def get_messages(self, count=1, block=True, timeout=0.1):
"""
Fetch the specified number of messages
count: Indicates the maximum number of messages to be fetched
block: If True, the API will block till some messages are fetched.
timeout: If block is True, the function will block for the specified
time (in seconds) until count messages is fetched. If None,
it will block forever.
"""
if self.consumer is None:
return []
else:
try:
messages = self.consumer.get_messages(count, block, timeout)
if not messages and self.zkp.failed:
raise FailedPayloadsError
return messages
except FailedPayloadsError as err:
msg = 'Failed to retrieve payload, restarting consumer'
self.logger.exception(msg)
raise err
def get_message(self, block=True, timeout=0.1, get_partition_info=None):
return self.consumer.get_message(block, timeout, get_partition_info)
def _get_message(self,
block=True,
timeout=0.1,
get_partition_info=None,
update_offset=True):
return self.consumer._get_message(block, timeout, get_partition_info,
update_offset)
def __iter__(self):
for msg in self.consumer:
yield msg
