text: #
  # Copyright 2015 Cisco 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 kafka
  from oslo_log import log
  from oslo_serialization import jsonutils
  from oslo_utils import netutils
  from six.moves.urllib import parse as urlparse
  
  from ceilometer.i18n import _LE
  from ceilometer.publisher import messaging
  
  LOG = log.getLogger(__name__)
  
  
  class KafkaBrokerPublisher(messaging.MessagingPublisher):
      """Publish metering data to kafka broker.
  
      The ip address and port number of kafka broker should be configured in
      ceilometer pipeline configuration file. If an ip address is not specified,
      this kafka publisher will not publish any meters.
  
      To enable this publisher, add the following section to the
      /etc/ceilometer/pipeline.yaml file or simply add it to an existing
      pipeline::
  
          meter:
              - name: meter_kafka
              interval: 600
              counters:
                  - "*"
              transformers:
              sinks:
                  - kafka_sink
          sinks:
              - name: kafka_sink
              transformers:
              publishers:
                  - kafka://[kafka_broker_ip]:[kafka_broker_port]?topic=[topic]
  
      Kafka topic name and broker's port are required for this publisher to work
      properly. If topic parameter is missing, this kafka publisher publish
      metering data under a topic name, 'ceilometer'. If the port number is not
      specified, this Kafka Publisher will use 9092 as the broker's port.
      This publisher has transmit options such as queue, drop, and retry. These
      options are specified using policy field of URL parameter. When queue
      option could be selected, local queue length can be determined using
      max_queue_length field as well. When the transfer fails with retry
      option, try to resend the data as many times as specified in max_retry
      field. If max_retry is not specified, default the number of retry is 100.
      """
  
      def __init__(self, parsed_url):
          super(KafkaBrokerPublisher, self).__init__(parsed_url)
          options = urlparse.parse_qs(parsed_url.query)
  
          self._producer = None
          self._host, self._port = netutils.parse_host_port(
              parsed_url.netloc, default_port=9092)
          self._topic = options.get('topic', ['ceilometer'])[-1]
          self.max_retry = int(options.get('max_retry', [100])[-1])
  
      def _ensure_connection(self):
          if self._producer:
              return
  
          try:
              client = kafka.KafkaClient("%s:%s" % (self._host, self._port))
              self._producer = kafka.SimpleProducer(client)
          except Exception as e:
              LOG.exception(_LE("Failed to connect to Kafka service: %s"), e)
              raise messaging.DeliveryFailure('Kafka Client is not available, '
                                              'please restart Kafka client')
  
      def _send(self, event_type, data):
          self._ensure_connection()
          # TODO(sileht): don't split the payload into multiple network
          # message ... but how to do that without breaking consuming
          # application...
          try:
              for d in data:
                  self._producer.send_messages(self._topic, jsonutils.dumps(d))
          except Exception as e:
              messaging.raise_delivery_failure(e)
  