| # |
| # Copyright 2016 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.producer import Producer as _kafkaProducer |
| from structlog import get_logger |
| from voltha.consulhelpers import get_endpoint_from_consul |
| from twisted.internet.defer import inlineCallbacks |
| from afkak.common import ( |
| PRODUCER_ACK_LOCAL_WRITE, |
| ) |
| |
| |
| 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): |
| |
| # return an exception if the object already exist |
| if KafkaProxy._kafka_instance: |
| raise Exception('Singleton exist for :{}'.format(KafkaProxy)) |
| |
| self.log = get_logger() |
| |
| self.log.info('KafkaProxy init with kafka endpoint:{}'.format( |
| 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.kclient = None |
| self.kproducer = None |
| |
| self._get_kafka_producer() |
| |
| KafkaProxy._kafka_instance = self |
| |
| def _get_kafka_producer(self): |
| # PRODUCER_ACK_LOCAL_WRITE : server will wait till the data is written |
| # to a local log before sending response |
| |
| if self.kafka_endpoint.startswith('@'): |
| try: |
| _k_endpoint = get_endpoint_from_consul(self.consul_endpoint, |
| self.kafka_endpoint[1:]) |
| self.log.info( |
| 'Found kafka service at {}'.format(_k_endpoint)) |
| |
| except Exception as e: |
| self.log.error('Failure to locate a kafka service from ' |
| 'consul {}:'.format(repr(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_LOCAL_WRITE, |
| ack_timeout=self.ack_timeout, |
| max_req_attempts=self.max_req_attempts) |
| |
| @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 |
| 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: |
| self.log.error('No kafka producer available at {}'.format( |
| self.kafka_endpoint)) |
| return |
| |
| self.log.info('Sending message {} to kafka topic {}'.format(msg, |
| topic)) |
| try: |
| msg_list = [msg] |
| yield self.kproducer.send_messages(topic, msgs=msg_list) |
| self.log.info('Successfully sent message {} to kafka topic ' |
| '{}'.format(msg, topic)) |
| except Exception as e: |
| self.log.error('Failure to send message {} to kafka topic {}: ' |
| '{}'.format(msg, topic, repr(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. |
| self.kproducer = None |
| self.kclient = None |
| |
| |
| # Common method to get the singleton instance of the kafka proxy class |
| def get_kafka_proxy(): |
| return KafkaProxy._kafka_instance |