# 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)