trunk/core/src/main/scala/kafka/producer/ProducerConfig.scala

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
*/

package kafka.producer

import async.AsyncProducerConfigShared
import java.util.Properties
import kafka.utils.{ZKConfig, Utils}
import kafka.common.InvalidConfigException

class ProducerConfig(val props: Properties) extends ZKConfig(props)
        with AsyncProducerConfigShared with SyncProducerConfigShared{

  /** For bypassing zookeeper based auto partition discovery, use this config   *
   *  to pass in static broker and per-broker partition information. Format-    *
   *  brokerid1:host1:port1, brokerid2:host2:port2*/
  val brokerList = Utils.getString(props, "broker.list", null)
  if(Utils.propertyExists(brokerList) && Utils.getString(props, "partitioner.class", null) != null)
    throw new InvalidConfigException("partitioner.class cannot be used when broker.list is set")

  /**
   * If DefaultEventHandler is used, this specifies the number of times to
   * retry if an error is encountered during send. Currently, it is only
   * appropriate when broker.list points to a VIP. If the zk.connect option
   * is used instead, this will not have any effect because with the zk-based
   * producer, brokers are not re-selected upon retry. So retries would go to
   * the same (potentially still down) broker. (KAFKA-253 will help address
   * this.)
   */
  val numRetries = Utils.getInt(props, "num.retries", 0)

  /** If both broker.list and zk.connect options are specified, throw an exception */
  if(Utils.propertyExists(brokerList) && Utils.propertyExists(zkConnect))
    throw new InvalidConfigException("only one of broker.list and zk.connect can be specified")

  if(!Utils.propertyExists(zkConnect) && !Utils.propertyExists(brokerList))
    throw new InvalidConfigException("At least one of zk.connect or broker.list must be specified")

  /** the partitioner class for partitioning events amongst sub-topics */
  val partitionerClass = Utils.getString(props, "partitioner.class", "kafka.producer.DefaultPartitioner")

  /** this parameter specifies whether the messages are sent asynchronously *
   * or not. Valid values are - async for asynchronous send                 *
   *                            sync for synchronous send                   */
  val producerType = Utils.getString(props, "producer.type", "sync")

  /**
   * This parameter allows you to specify the compression codec for all data generated *
   * by this producer. The default is NoCompressionCodec
   */
  val compressionCodec = Utils.getCompressionCodec(props, "compression.codec")

  /** This parameter allows you to set whether compression should be turned *
   *  on for particular topics
   *
   *  If the compression codec is anything other than NoCompressionCodec,
   *
   *    Enable compression only for specified topics if any
   *
   *    If the list of compressed topics is empty, then enable the specified compression codec for all topics
   *
   *  If the compression codec is NoCompressionCodec, compression is disabled for all topics
   */
  val compressedTopics = Utils.getCSVList(Utils.getString(props, "compressed.topics", null))

  /**
   * The producer using the zookeeper software load balancer maintains a ZK cache that gets
   * updated by the zookeeper watcher listeners. During some events like a broker bounce, the
   * producer ZK cache can get into an inconsistent state, for a small time period. In this time
   * period, it could end up picking a broker partition that is unavailable. When this happens, the
   * ZK cache needs to be updated.
   * This parameter specifies the number of times the producer attempts to refresh this ZK cache.
   */
  val zkReadRetries = Utils.getInt(props, "zk.read.num.retries", 3)
}