oslo.messaging/oslo_messaging/_drivers/impl_kafka.py
Andy Smith 0953fa1759 Kafka driver deployment guide
Depends-On: Idfb9fe3700d882c8285c6dc56b0620951178eba2
Change-Id: If8370c0c83312d675bde837f768ae40ec3603972
2019-01-23 08:27:43 -05:00

457 lines
16 KiB
Python

# Copyright (C) 2015 Cisco Systems, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import logging
import threading
import confluent_kafka
from confluent_kafka import KafkaException
from oslo_serialization import jsonutils
from oslo_utils import eventletutils
from oslo_utils import importutils
from oslo_messaging._drivers import base
from oslo_messaging._drivers import common as driver_common
from oslo_messaging._drivers.kafka_driver import kafka_options
if eventletutils.EVENTLET_AVAILABLE:
tpool = importutils.try_import('eventlet.tpool')
LOG = logging.getLogger(__name__)
def unpack_message(msg):
"""Unpack context and msg."""
context = {}
message = None
msg = jsonutils.loads(msg)
message = driver_common.deserialize_msg(msg)
context = message['_context']
del message['_context']
return context, message
def pack_message(ctxt, msg):
"""Pack context into msg."""
if isinstance(ctxt, dict):
context_d = ctxt
else:
context_d = ctxt.to_dict()
msg['_context'] = context_d
msg = driver_common.serialize_msg(msg)
return msg
def concat(sep, items):
return sep.join(filter(bool, items))
def target_to_topic(target, priority=None, vhost=None):
"""Convert target into topic string
:param target: Message destination target
:type target: oslo_messaging.Target
:param priority: Notification priority
:type priority: string
:param priority: Notification vhost
:type priority: string
"""
return concat(".", [target.topic, priority, vhost])
class ConsumerTimeout(KafkaException):
pass
class AssignedPartition(object):
"""This class is used by the ConsumerConnection to track the
assigned partitions.
"""
def __init__(self, topic, partition):
super(AssignedPartition, self).__init__()
self.topic = topic
self.partition = partition
self.skey = '%s %d' % (self.topic, self.partition)
def to_dict(self):
return {'topic': self.topic, 'partition': self.partition}
class Connection(object):
"""This is the base class for consumer and producer connections for
transport attributes.
"""
def __init__(self, conf, url):
self.driver_conf = conf.oslo_messaging_kafka
self.security_protocol = self.driver_conf.security_protocol
self.sasl_mechanism = self.driver_conf.sasl_mechanism
self.ssl_cafile = self.driver_conf.ssl_cafile
self.url = url
self.virtual_host = url.virtual_host
self._parse_url()
def _parse_url(self):
self.hostaddrs = []
self.username = None
self.password = None
for host in self.url.hosts:
# NOTE(ansmith): connections and failover are transparently
# managed by the client library. Credentials will be
# selectd from first host encountered in transport_url
if self.username is None:
self.username = host.username
self.password = host.password
else:
if self.username != host.username:
LOG.warning("Different transport usernames detected")
if host.hostname:
self.hostaddrs.append("%s:%s" % (host.hostname, host.port))
def reset(self):
"""Reset a connection so it can be used again."""
pass
class ConsumerConnection(Connection):
"""This is the class for kafka topic/assigned partition consumer
"""
def __init__(self, conf, url):
super(ConsumerConnection, self).__init__(conf, url)
self.consumer = None
self.consumer_timeout = self.driver_conf.kafka_consumer_timeout
self.max_fetch_bytes = self.driver_conf.kafka_max_fetch_bytes
self.group_id = self.driver_conf.consumer_group
self.use_auto_commit = self.driver_conf.enable_auto_commit
self.max_poll_records = self.driver_conf.max_poll_records
self._consume_loop_stopped = False
self.assignment_dict = dict()
def find_assignment(self, topic, partition):
"""Find and return existing assignment based on topic and partition"""
skey = '%s %d' % (topic, partition)
return self.assignment_dict.get(skey)
def on_assign(self, consumer, topic_partitions):
"""Rebalance on_assign callback"""
assignment = [AssignedPartition(p.topic, p.partition)
for p in topic_partitions]
self.assignment_dict = {a.skey: a for a in assignment}
for t in topic_partitions:
LOG.debug("Topic %s assigned to partition %d",
t.topic, t.partition)
def on_revoke(self, consumer, topic_partitions):
"""Rebalance on_revoke callback"""
self.assignment_dict = dict()
for t in topic_partitions:
LOG.debug("Topic %s revoked from partition %d",
t.topic, t.partition)
def _poll_messages(self, timeout):
"""Consume messages, callbacks and return list of messages"""
msglist = self.consumer.consume(self.max_poll_records,
timeout)
if ((len(self.assignment_dict) == 0) or (len(msglist) == 0)):
raise ConsumerTimeout()
messages = []
for message in msglist:
if message is None:
break
a = self.find_assignment(message.topic(), message.partition())
if a is None:
LOG.warning(("Message for %s received on unassigned "
"partition %d"),
message.topic(), message.partition())
else:
messages.append(message.value())
if not self.use_auto_commit:
self.consumer.commit(asynchronous=False)
return messages
def consume(self, timeout=None):
"""Receive messages.
:param timeout: poll timeout in seconds
"""
def _raise_timeout(exc):
raise driver_common.Timeout(str(exc))
timer = driver_common.DecayingTimer(duration=timeout)
timer.start()
poll_timeout = (self.consumer_timeout if timeout is None
else min(timeout, self.consumer_timeout))
while True:
if self._consume_loop_stopped:
return
try:
if eventletutils.is_monkey_patched('thread'):
return tpool.execute(self._poll_messages, poll_timeout)
return self._poll_messages(poll_timeout)
except ConsumerTimeout as exc:
poll_timeout = timer.check_return(
_raise_timeout, exc, maximum=self.consumer_timeout)
except Exception:
LOG.exception("Failed to consume messages")
return
def stop_consuming(self):
self._consume_loop_stopped = True
def close(self):
if self.consumer:
self.consumer.close()
self.consumer = None
def declare_topic_consumer(self, topics, group=None):
conf = {
'bootstrap.servers': ",".join(self.hostaddrs),
'group.id': (group or self.group_id),
'enable.auto.commit': self.use_auto_commit,
'max.partition.fetch.bytes': self.max_fetch_bytes,
'security.protocol': self.security_protocol,
'sasl.mechanism': self.sasl_mechanism,
'sasl.username': self.username,
'sasl.password': self.password,
'ssl.ca.location': self.ssl_cafile,
'enable.partition.eof': False,
'default.topic.config': {'auto.offset.reset': 'latest'}
}
LOG.debug("Subscribing to %s as %s", topics, (group or self.group_id))
self.consumer = confluent_kafka.Consumer(conf)
self.consumer.subscribe(topics,
on_assign=self.on_assign,
on_revoke=self.on_revoke)
class ProducerConnection(Connection):
def __init__(self, conf, url):
super(ProducerConnection, self).__init__(conf, url)
self.batch_size = self.driver_conf.producer_batch_size
self.linger_ms = self.driver_conf.producer_batch_timeout * 1000
self.producer = None
self.producer_lock = threading.Lock()
def _produce_message(self, topic, message):
while True:
try:
self.producer.produce(topic, message)
except KafkaException as e:
LOG.error("Produce message failed: %s" % str(e))
except BufferError:
LOG.debug("Produce message queue full, waiting for deliveries")
self.producer.poll(0.5)
continue
break
self.producer.poll(0)
def notify_send(self, topic, ctxt, msg, retry):
"""Send messages to Kafka broker.
:param topic: String of the topic
:param ctxt: context for the messages
:param msg: messages for publishing
:param retry: the number of retry
"""
retry = retry if retry >= 0 else None
message = pack_message(ctxt, msg)
message = jsonutils.dumps(message).encode('utf-8')
try:
self._ensure_producer()
if eventletutils.is_monkey_patched('thread'):
return tpool.execute(self._produce_message, topic, message)
return self._produce_message(topic, message)
except Exception:
# NOTE(sileht): if something goes wrong close the producer
# connection
self._close_producer()
raise
def close(self):
self._close_producer()
def _close_producer(self):
with self.producer_lock:
if self.producer:
try:
self.producer.flush()
except KafkaException:
LOG.error("Flush error during producer close")
self.producer = None
def _ensure_producer(self):
if self.producer:
return
with self.producer_lock:
if self.producer:
return
conf = {
'bootstrap.servers': ",".join(self.hostaddrs),
'linger.ms': self.linger_ms,
'batch.num.messages': self.batch_size,
'security.protocol': self.security_protocol,
'sasl.mechanism': self.sasl_mechanism,
'sasl.username': self.username,
'sasl.password': self.password,
'ssl.ca.location': self.ssl_cafile
}
self.producer = confluent_kafka.Producer(conf)
class OsloKafkaMessage(base.RpcIncomingMessage):
def __init__(self, ctxt, message):
super(OsloKafkaMessage, self).__init__(ctxt, message)
def requeue(self):
LOG.warning("requeue is not supported")
def reply(self, reply=None, failure=None):
LOG.warning("reply is not supported")
def heartbeat(self):
LOG.warning("heartbeat is not supported")
class KafkaListener(base.PollStyleListener):
def __init__(self, conn):
super(KafkaListener, self).__init__()
self._stopped = threading.Event()
self.conn = conn
self.incoming_queue = []
# FIXME(sileht): We do a first poll to ensure we topics are created
# This is a workaround mainly for functional tests, in real life
# this is fine if topics are not created synchroneously
self.poll(5)
@base.batch_poll_helper
def poll(self, timeout=None):
while not self._stopped.is_set():
if self.incoming_queue:
return self.incoming_queue.pop(0)
try:
messages = self.conn.consume(timeout=timeout) or []
for message in messages:
msg = OsloKafkaMessage(*unpack_message(message))
self.incoming_queue.append(msg)
except driver_common.Timeout:
return None
def stop(self):
self._stopped.set()
self.conn.stop_consuming()
def cleanup(self):
self.conn.close()
class KafkaDriver(base.BaseDriver):
"""Kafka Driver
See :doc:`kafka` for details.
"""
def __init__(self, conf, url, default_exchange=None,
allowed_remote_exmods=None):
conf = kafka_options.register_opts(conf, url)
super(KafkaDriver, self).__init__(
conf, url, default_exchange, allowed_remote_exmods)
self.listeners = []
self.virtual_host = url.virtual_host
self.pconn = ProducerConnection(conf, url)
def cleanup(self):
self.pconn.close()
for c in self.listeners:
c.close()
self.listeners = []
LOG.info("Kafka messaging driver shutdown")
def send(self, target, ctxt, message, wait_for_reply=None, timeout=None,
call_monitor_timeout=None, retry=None):
raise NotImplementedError(
'The RPC implementation for Kafka is not implemented')
def send_notification(self, target, ctxt, message, version, retry=None):
"""Send notification to Kafka brokers
:param target: Message destination target
:type target: oslo_messaging.Target
:param ctxt: Message context
:type ctxt: dict
:param message: Message payload to pass
:type message: dict
:param version: Messaging API version (currently not used)
:type version: str
:param call_monitor_timeout: Maximum time the client will wait for the
call to complete before or receive a message heartbeat indicating
the remote side is still executing.
:type call_monitor_timeout: float
:param retry: an optional default kafka consumer retries configuration
None means to retry forever
0 means no retry
N means N retries
:type retry: int
"""
self.pconn.notify_send(target_to_topic(target,
vhost=self.virtual_host),
ctxt, message, retry)
def listen(self, target, batch_size, batch_timeout):
raise NotImplementedError(
'The RPC implementation for Kafka is not implemented')
def listen_for_notifications(self, targets_and_priorities, pool,
batch_size, batch_timeout):
"""Listen to a specified list of targets on Kafka brokers
:param targets_and_priorities: List of pairs (target, priority)
priority is not used for kafka driver
target.exchange_target.topic is used as
a kafka topic
:type targets_and_priorities: list
:param pool: consumer group of Kafka consumers
:type pool: string
"""
conn = ConsumerConnection(self.conf, self._url)
topics = []
for target, priority in targets_and_priorities:
topics.append(target_to_topic(target, priority))
conn.declare_topic_consumer(topics, pool)
listener = KafkaListener(conn)
return base.PollStyleListenerAdapter(listener, batch_size,
batch_timeout)