| # |
| # Copyright 2017 the original author or authors. |
| # |
| # 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. |
| # |
| |
| from afkak.client import KafkaClient as _KafkaClient |
| from afkak.common import ( |
| PRODUCER_ACK_LOCAL_WRITE, PRODUCER_ACK_NOT_REQUIRED |
| ) |
| from afkak.producer import Producer as _kafkaProducer |
| from structlog import get_logger |
| from twisted.internet.defer import inlineCallbacks, returnValue |
| from zope.interface import implementer |
| |
| from adapters.common.utils.consulhelpers import get_endpoint_from_consul |
| from adapters.kafka.event_bus_publisher import EventBusPublisher |
| from adapters.common.utils.registry import IComponent |
| import time |
| |
| log = get_logger() |
| |
| |
| @implementer(IComponent) |
| class KafkaProxy(object): |
| """ |
| This is a singleton proxy kafka class to hide the kafka client details. |
| """ |
| _kafka_instance = None |
| |
| def __init__(self, |
| consul_endpoint='localhost:8500', |
| kafka_endpoint='localhost:9092', |
| ack_timeout=1000, |
| max_req_attempts=10, |
| config={}): |
| |
| # return an exception if the object already exist |
| if KafkaProxy._kafka_instance: |
| raise Exception('Singleton exist for :{}'.format(KafkaProxy)) |
| |
| log.debug('initializing', endpoint=kafka_endpoint) |
| self.ack_timeout = ack_timeout |
| self.max_req_attempts = max_req_attempts |
| self.consul_endpoint = consul_endpoint |
| self.kafka_endpoint = kafka_endpoint |
| self.config = config |
| self.kclient = None |
| self.kproducer = None |
| self.event_bus_publisher = None |
| self.stopping = False |
| self.faulty = False |
| log.debug('initialized', endpoint=kafka_endpoint) |
| |
| @inlineCallbacks |
| def start(self): |
| log.debug('starting') |
| self._get_kafka_producer() |
| KafkaProxy._kafka_instance = self |
| self.event_bus_publisher = yield EventBusPublisher( |
| self, self.config.get('event_bus_publisher', {})).start() |
| log.info('started') |
| KafkaProxy.faulty = False |
| self.stopping = False |
| returnValue(self) |
| |
| @inlineCallbacks |
| def stop(self): |
| try: |
| log.debug('stopping-kafka-proxy') |
| try: |
| if self.kclient: |
| yield self.kclient.close() |
| self.kclient = None |
| log.debug('stopped-kclient-kafka-proxy') |
| except Exception, e: |
| log.exception('failed-stopped-kclient-kafka-proxy', e=e) |
| pass |
| |
| try: |
| if self.kproducer: |
| yield self.kproducer.stop() |
| self.kproducer = None |
| log.debug('stopped-kproducer-kafka-proxy') |
| except Exception, e: |
| log.exception('failed-stopped-kproducer-kafka-proxy', e=e) |
| pass |
| |
| #try: |
| # if self.event_bus_publisher: |
| # yield self.event_bus_publisher.stop() |
| # self.event_bus_publisher = None |
| # log.debug('stopped-event-bus-publisher-kafka-proxy') |
| #except Exception, e: |
| # log.debug('failed-stopped-event-bus-publisher-kafka-proxy') |
| # pass |
| |
| log.debug('stopped-kafka-proxy') |
| |
| except Exception, e: |
| self.kclient = None |
| self.kproducer = None |
| #self.event_bus_publisher = None |
| log.exception('failed-stopped-kafka-proxy', e=e) |
| pass |
| |
| def _get_kafka_producer(self): |
| # PRODUCER_ACK_LOCAL_WRITE : server will wait till the data is written |
| # to a local log before sending response |
| try: |
| |
| if self.kafka_endpoint.startswith('@'): |
| try: |
| _k_endpoint = get_endpoint_from_consul(self.consul_endpoint, |
| self.kafka_endpoint[1:]) |
| log.debug('found-kafka-service', endpoint=_k_endpoint) |
| |
| except Exception as e: |
| log.exception('no-kafka-service-in-consul', e=e) |
| |
| self.kproducer = None |
| self.kclient = None |
| return |
| else: |
| _k_endpoint = self.kafka_endpoint |
| |
| self.kclient = _KafkaClient(_k_endpoint) |
| self.kproducer = _kafkaProducer(self.kclient, |
| req_acks=PRODUCER_ACK_NOT_REQUIRED, |
| # req_acks=PRODUCER_ACK_LOCAL_WRITE, |
| # ack_timeout=self.ack_timeout, |
| # max_req_attempts=self.max_req_attempts) |
| ) |
| except Exception, e: |
| log.exception('failed-get-kafka-producer', e=e) |
| return |
| |
| @inlineCallbacks |
| def send_message(self, topic, msg): |
| assert topic is not None |
| assert msg is not None |
| |
| # first check whether we have a kafka producer. If there is none |
| # then try to get one - this happens only when we try to lookup the |
| # kafka service from consul |
| try: |
| if self.faulty is False: |
| |
| if self.kproducer is None: |
| self._get_kafka_producer() |
| # Lets the next message request do the retry if still a failure |
| if self.kproducer is None: |
| log.error('no-kafka-producer', endpoint=self.kafka_endpoint) |
| return |
| |
| # log.debug('sending-kafka-msg', topic=topic, msg=msg) |
| msgs = [msg] |
| |
| if self.kproducer and self.kclient and \ |
| self.event_bus_publisher and self.faulty is False: |
| # log.debug('sending-kafka-msg-I-am-here0', time=int(round(time.time() * 1000))) |
| |
| yield self.kproducer.send_messages(topic, msgs=msgs) |
| # self.kproducer.send_messages(topic, msgs=msgs) |
| # log.debug('sent-kafka-msg', topic=topic, msg=msg) |
| else: |
| return |
| |
| except Exception, e: |
| self.faulty = True |
| log.error('failed-to-send-kafka-msg', topic=topic, msg=msg, e=e) |
| |
| # set the kafka producer to None. This is needed if the |
| # kafka docker went down and comes back up with a different |
| # port number. |
| if self.stopping is False: |
| log.debug('stopping-kafka-proxy') |
| try: |
| self.stopping = True |
| self.stop() |
| self.stopping = False |
| self.faulty = False |
| log.debug('stopped-kafka-proxy') |
| except Exception, e: |
| log.exception('failed-stopping-kafka-proxy', e=e) |
| pass |
| else: |
| log.info('already-stopping-kafka-proxy') |
| |
| return |
| |
| def is_faulty(self): |
| return self.faulty |
| |
| |
| # Common method to get the singleton instance of the kafka proxy class |
| def get_kafka_proxy(): |
| return KafkaProxy._kafka_instance |
| |