kafka.server.KafkaZooKeeper.scala Maven / Gradle / Ivy

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/**
 * 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.server

import kafka.utils._
import org.apache.zookeeper.Watcher.Event.KeeperState
import org.I0Itec.zkclient.{IZkStateListener, ZkClient}
import kafka.common._
import java.net.InetAddress


/**
 * Handles registering broker with zookeeper in the following path:
 *   /brokers/[0...N] --> host:port
 */
class KafkaZooKeeper(config: KafkaConfig) extends Logging {

  val brokerIdPath = ZkUtils.BrokerIdsPath + "/" + config.brokerId
  private var zkClient: ZkClient = null

   def startup() {
     /* start client */
     info("connecting to ZK: " + config.zkConnect)
     zkClient = KafkaZookeeperClient.getZookeeperClient(config)
     zkClient.subscribeStateChanges(new SessionExpireListener)
     registerBrokerInZk()
   }

  private def registerBrokerInZk() {
    val hostName = 
      if(config.hostName == null || config.hostName.trim.isEmpty) 
        InetAddress.getLocalHost.getCanonicalHostName 
      else
        config.hostName 
    val jmxPort = System.getProperty("com.sun.management.jmxremote.port", "-1").toInt
    ZkUtils.registerBrokerInZk(zkClient, config.brokerId, hostName, config.port, jmxPort)
  }

  /**
   *  When we get a SessionExpired event, we lost all ephemeral nodes and zkclient has reestablished a
   *  connection for us. We need to re-register this broker in the broker registry.
   */
  class SessionExpireListener() extends IZkStateListener {
    @throws(classOf[Exception])
    def handleStateChanged(state: KeeperState) {
      // do nothing, since zkclient will do reconnect for us.
    }

    /**
     * Called after the zookeeper session has expired and a new session has been created. You would have to re-create
     * any ephemeral nodes here.
     *
     * @throws Exception
     *             On any error.
     */
    @throws(classOf[Exception])
    def handleNewSession() {
      info("re-registering broker info in ZK for broker " + config.brokerId)
      registerBrokerInZk()
      info("done re-registering broker")
      info("Subscribing to %s path to watch for new topics".format(ZkUtils.BrokerTopicsPath))
    }
  }

  def shutdown() {
    if (zkClient != null) {
      info("Closing zookeeper client...")
      zkClient.close()
    }
  }

  def getZookeeperClient = {
    zkClient
  }
}