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概述
Kafka源码包含多个模块，每个模块负责不同的功能。以下是一些核心模块及其功能的概述：
服务端源码 ：实现Kafka Broker的核心功能，包括日志存储、控制器、协调器、元数据管理及状态机管理、延迟机制、消费者组管理、高并发网络架构模型实现等。
Java客户端源码 ：实现了Producer和Consumer与Broker的交互机制，以及通用组件支撑代码。
Connect源码 ：用来构建异构数据双向流式同步服务。
Stream源码 ：用来实现实时流处理相关功能。
Raft源码 ：实现了Raft一致性协议。
Admin模块 ：Kafka的管理员模块，操作和管理其topic，partition相关，包含创建，删除topic，或者拓展分区等。
Api模块 ：负责数据交互，客户端与服务端交互数据的编码与解码。
Client模块 ：包含Producer读取Kafka Broker元数据信息的类，如topic和分区，以及leader。
Cluster模块 ：包含Broker、Cluster、Partition、Replica等实体类。
Common模块 ：包含各种异常类以及错误验证。
Consumer模块 ：消费者处理模块，负责客户端消费者数据和逻辑处理。
Controller模块 ：负责中央控制器的选举，分区的Leader选举，Replica的分配或重新分配，分区和副本的扩容等。
Coordinator模块 ：负责管理部分consumer group和他们的offset。
Javaapi模块 ：提供Java语言的Producer和Consumer的API接口。
Log模块 ：负责Kafka文件存储，读写所有Topic消息数据。
Message模块 ：封装多条数据组成数据集或压缩数据集。
Metrics模块 ：负责内部状态监控。
Network模块 ：处理客户端连接，网络事件模块。
Producer模块 ：生产者细节实现，包括同步和异步消息发送。
Security模块 ：负责Kafka的安全验证和管理。
Serializer模块 ：序列化和反序列化消息内容。
Server模块 ：涉及Leader和Offset的checkpoint，动态配置，延时创建和删除Topic，Leader选举，Admin和Replica管理等。
Tools模块 ：包含多种工具，如导出consumer offset值，LogSegments信息，Topic的log位置信息，Zookeeper上的offset值等。
Utils模块 ：包含各种工具类，如Json，ZkUtils，线程池工具类，KafkaScheduler公共调度器类等。
这些模块共同构成了Kafka的整体架构，使其能够提供高吞吐量、高可用性的消息队列服务。
kafka源码分支为1.0.2
kafka.controller.ControllerChannelManager类：
/** * 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.controller import java.net.SocketTimeoutException import java.util.concurrent.{BlockingQueue, LinkedBlockingQueue} import com.yammer.metrics.core.Gauge import kafka.api._ import kafka.cluster.Broker import kafka.common.{KafkaException, TopicAndPartition} import kafka.metrics.KafkaMetricsGroup import kafka.server.KafkaConfig import kafka.utils._ import org.apache.kafka.clients._ import org.apache.kafka.common.metrics.Metrics import org.apache.kafka.common.network._ import org.apache.kafka.common.protocol.ApiKeys import org.apache.kafka.common.requests.UpdateMetadataRequest.EndPoint import org.apache.kafka.common.requests._ import org.apache.kafka.common.security.JaasContext import org.apache.kafka.common.security.auth.SecurityProtocol import org.apache.kafka.common.utils.{LogContext, Time} import org.apache.kafka.common.{Node, TopicPartition} import scala.collection.JavaConverters._ import scala.collection.mutable.HashMap import scala.collection.{Set, mutable} object ControllerChannelManager { val QueueSizeMetricName = "QueueSize" } //在 Kafka 中，ControllerChannelManager 是一个关键组件，负责管理控制器与其它 Kafka 代理（Broker）之间的通信。 // 控制器（Controller）是 Kafka 集群中的一个特殊角色，负责管理集群的元数据和协调集群的操作，如分区分配、副本同步等。 // //ControllerChannelManager 的主要功能包括： //管理通信通道：维护控制器与各个 Broker 之间的网络连接和通信通道。 //发送控制命令：向 Broker 发送控制命令，如分区重分配、副本同步等。 //接收响应：接收 Broker 发送的响应和状态更新。 //处理失败和重试：处理与 Broker 通信过程中可能出现的失败，并进行重试。 //监控和统计：监控通信状态和性能，收集统计信息。 //KafkaController 通过发送特定的请求来与 broker 通信。这些请求包括但不限于： //LeaderAndIsrRequest：用于更新分区的 leader 和 ISR（In-Sync Replicas）。 //StopReplicaRequest：用于停止某个分区的副本。 //UpdateMetadataRequest：用于更新分区的元数据信息。 //ReassignPartitionsRequest：用于重新分配分区的副本。 //ControllerChannelManager 在初始化时，会为集群中的每个节点初始化一个 ControllerBrokerStateInfo 对象，该对象包含四个部分： // //NetworkClient：网络连接对象； //Node：节点信息； //BlockingQueue：请求队列； //RequestSendThread：请求的发送线程。 //其具体实现如下所示： class ControllerChannelManager(controllerContext: ControllerContext, config: KafkaConfig, time: Time, metrics: Metrics, stateChangeLogger: StateChangeLogger, threadNamePrefix: Option[String] = None) extends Logging with KafkaMetricsGroup { import ControllerChannelManager._ protected val brokerStateInfo = new HashMap[Int, ControllerBrokerStateInfo] private val brokerLock = new Object this.logIdent = "[Channel manager on controller " + config.brokerId + "]: " newGauge( "TotalQueueSize", new Gauge[Int] { def value: Int = brokerLock synchronized { brokerStateInfo.values.iterator.map(_.messageQueue.size).sum } } ) //会为每个broker创建对应的RequestSendThread线程 controllerContext.liveBrokers.foreach(addNewBroker) def startup() = { brokerLock synchronized { brokerStateInfo.foreach(brokerState => startRequestSendThread(brokerState._1)) } } def shutdown() = { brokerLock synchronized { brokerStateInfo.values.foreach(removeExistingBroker) } } //向 broker 发送请求（并没有真正发送,只是添加到对应的 queue 中）, 请求的的发送是在 每台 Broker 对应的 RequestSendThread 中处理的。 def sendRequest(brokerId: Int, apiKey: ApiKeys, request: AbstractRequest.Builder[_ <: AbstractRequest], callback: AbstractResponse => Unit = null) { brokerLock synchronized { val stateInfoOpt = brokerStateInfo.get(brokerId) stateInfoOpt match { case Some(stateInfo) => stateInfo.messageQueue.put(QueueItem(apiKey, request, callback)) case None => warn("Not sending request %s to broker %d, since it is offline.".format(request, brokerId)) } } } def addBroker(broker: Broker) { // be careful here. Maybe the startup() API has already started the request send thread brokerLock synchronized { if(!brokerStateInfo.contains(broker.id)) { addNewBroker(broker) startRequestSendThread(broker.id) } } } def removeBroker(brokerId: Int) { brokerLock synchronized { removeExistingBroker(brokerStateInfo(brokerId)) } } private def addNewBroker(broker: Broker) { val messageQueue = new LinkedBlockingQueue[QueueItem] debug("Controller %d trying to connect to broker %d".format(config.brokerId, broker.id)) val brokerNode = broker.getNode(config.interBrokerListenerName) val logContext = new LogContext(s"[Controller id=${config.brokerId}, targetBrokerId=${brokerNode.idString}] ") val networkClient = { val channelBuilder = ChannelBuilders.clientChannelBuilder( config.interBrokerSecurityProtocol, JaasContext.Type.SERVER, config, config.interBrokerListenerName, config.saslMechanismInterBrokerProtocol, config.saslInterBrokerHandshakeRequestEnable ) val selector = new Selector( NetworkReceive.UNLIMITED, Selector.NO_IDLE_TIMEOUT_MS, metrics, time, "controller-channel", Map("broker-id" -> brokerNode.idString).asJava, false, channelBuilder, logContext ) new NetworkClient( selector, new ManualMetadataUpdater(Seq(brokerNode).asJava), config.brokerId.toString, 1, 0, 0, Selectable.USE_DEFAULT_BUFFER_SIZE, Selectable.USE_DEFAULT_BUFFER_SIZE, config.requestTimeoutMs, time, false, new ApiVersions, logContext ) } val threadName = threadNamePrefix match { case None => "Controller-%d-to-broker-%d-send-thread".format(config.brokerId, broker.id) case Some(name) => "%s:Controller-%d-to-broker-%d-send-thread".format(name, config.brokerId, broker.id) } val requestThread = new RequestSendThread(config.brokerId, controllerContext, messageQueue, networkClient, brokerNode, config, time, stateChangeLogger, threadName) requestThread.setDaemon(false) val queueSizeGauge = newGauge( QueueSizeMetricName, new Gauge[Int] { def value: Int = messageQueue.size }, queueSizeTags(broker.id) ) brokerStateInfo.put(broker.id, new ControllerBrokerStateInfo(networkClient, brokerNode, messageQueue, requestThread, queueSizeGauge)) } private def queueSizeTags(brokerId: Int) = Map("broker-id" -> brokerId.toString) private def removeExistingBroker(brokerState: ControllerBrokerStateInfo) { try { // Shutdown the RequestSendThread before closing the NetworkClient to avoid the concurrent use of the // non-threadsafe classes as described in KAFKA-4959. // The call to shutdownLatch.await() in ShutdownableThread.shutdown() serves as a synchronization barrier that // hands off the NetworkClient from the RequestSendThread to the ZkEventThread. brokerState.requestSendThread.shutdown() brokerState.networkClient.close() brokerState.messageQueue.clear() removeMetric(QueueSizeMetricName, queueSizeTags(brokerState.brokerNode.id)) brokerStateInfo.remove(brokerState.brokerNode.id) } catch { case e: Throwable => error("Error while removing broker by the controller", e) } } protected def startRequestSendThread(brokerId: Int) { val requestThread = brokerStateInfo(brokerId).requestSendThread if(requestThread.getState == Thread.State.NEW) requestThread.start() } } case class QueueItem(apiKey: ApiKeys, request: AbstractRequest.Builder[_ <: AbstractRequest], callback: AbstractResponse => Unit) class RequestSendThread(val controllerId: Int, val controllerContext: ControllerContext, val queue: BlockingQueue[QueueItem], val networkClient: NetworkClient, val brokerNode: Node, val config: KafkaConfig, val time: Time, val stateChangeLogger: StateChangeLogger, name: String) extends ShutdownableThread(name = name) { private val socketTimeoutMs = config.controllerSocketTimeoutMs override def doWork(): Unit = { def backoff(): Unit = CoreUtils.swallowTrace(Thread.sleep(100)) val QueueItem(apiKey, requestBuilder, callback) = queue.take() var clientResponse: ClientResponse = null try { var isSendSuccessful = false while (isRunning.get() && !isSendSuccessful) { // if a broker goes down for a long time, then at some point the controller's zookeeper listener will trigger a // removeBroker which will invoke shutdown() on this thread. At that point, we will stop retrying. try { if (!brokerReady()) { isSendSuccessful = false backoff() } else { val clientRequest = networkClient.newClientRequest(brokerNode.idString, requestBuilder, time.milliseconds(), true) clientResponse = NetworkClientUtils.sendAndReceive(networkClient, clientRequest, time) isSendSuccessful = true } } catch { case e: Throwable => // if the send was not successful, reconnect to broker and resend the message warn(("Controller %d epoch %d fails to send request %s to broker %s. " + "Reconnecting to broker.").format(controllerId, controllerContext.epoch, requestBuilder.toString, brokerNode.toString), e) networkClient.close(brokerNode.idString) isSendSuccessful = false backoff() } } if (clientResponse != null) { val requestHeader = clientResponse.requestHeader val api = requestHeader.apiKey if (api != ApiKeys.LEADER_AND_ISR && api != ApiKeys.STOP_REPLICA && api != ApiKeys.UPDATE_METADATA) throw new KafkaException(s"Unexpected apiKey received: $apiKey") val response = clientResponse.responseBody stateChangeLogger.withControllerEpoch(controllerContext.epoch).trace("Received response " + s"${response.toString(requestHeader.apiVersion)} for a request sent to broker $brokerNode") if (callback != null) { callback(response) } } } catch { case e: Throwable => error("Controller %d fails to send a request to broker %s".format(controllerId, brokerNode.toString), e) // If there is any socket error (eg, socket timeout), the connection is no longer usable and needs to be recreated. networkClient.close(brokerNode.idString) } } private def brokerReady(): Boolean = { try { if (!NetworkClientUtils.isReady(networkClient, brokerNode, time.milliseconds())) { if (!NetworkClientUtils.awaitReady(networkClient, brokerNode, time, socketTimeoutMs)) throw new SocketTimeoutException(s"Failed to connect within $socketTimeoutMs ms") info("Controller %d connected to %s for sending state change requests".format(controllerId, brokerNode.toString)) } true } catch { case e: Throwable => warn("Controller %d's connection to broker %s was unsuccessful".format(controllerId, brokerNode.toString), e) networkClient.close(brokerNode.idString) false } } } class ControllerBrokerRequestBatch(controller: KafkaController, stateChangeLogger: StateChangeLogger) extends Logging { val controllerContext = controller.controllerContext val controllerId: Int = controller.config.brokerId //记录每个 broker 与要发送的 LeaderAndIsr 请求集合的 map； val leaderAndIsrRequestMap = mutable.Map.empty[Int, mutable.Map[TopicPartition, LeaderAndIsrRequest.PartitionState]] //记录每个 broker 与要发送的 StopReplica 集合的 map； val stopReplicaRequestMap = mutable.Map.empty[Int, Seq[StopReplicaRequestInfo]] //记录要发送的 update-metadata 请求的 broker 集合； val updateMetadataRequestBrokerSet = mutable.Set.empty[Int] //记录 update-metadata 请求要更新的 Topic Partition 集合。 val updateMetadataRequestPartitionInfoMap = mutable.Map.empty[TopicPartition, UpdateMetadataRequest.PartitionState] //创建新的请求前, 需要确保前一批请求全部发送完毕，否则抛出异常 //这个方法的主要作用是检查上一波的 LeaderAndIsr、UpdateMetadata、StopReplica 请求是否已经发送， // 正常情况下，Controller 在调用 sendRequestsToBrokers() 方法之后，这些集合中的请求都会被发送，发送之后，会将相应的请求集合清空， // 当然在异常情况可能会导致部分集合没有被清空，导致无法 newBatch()，这种情况下，通常策略是重启 controller，因为现在 Controller 的设计还是有些复杂， // 在某些情况下还是可能会导致异常发生，并且有些异常还是无法恢复的。 def newBatch() { // raise error if the previous batch is not empty if (leaderAndIsrRequestMap.nonEmpty) throw new IllegalStateException("Controller to broker state change requests batch is not empty while creating " + "a new one. Some LeaderAndIsr state changes %s might be lost ".format(leaderAndIsrRequestMap.toString())) if (stopReplicaRequestMap.nonEmpty) throw new IllegalStateException("Controller to broker state change requests batch is not empty while creating a " + "new one. Some StopReplica state changes %s might be lost ".format(stopReplicaRequestMap.toString())) if (updateMetadataRequestBrokerSet.nonEmpty) throw new IllegalStateException("Controller to broker state change requests batch is not empty while creating a " + "new one. Some UpdateMetadata state changes to brokers %s with partition info %s might be lost ".format( updateMetadataRequestBrokerSet.toString(), updateMetadataRequestPartitionInfoMap.toString())) } def clear() { leaderAndIsrRequestMap.clear() stopReplicaRequestMap.clear() updateMetadataRequestBrokerSet.clear() updateMetadataRequestPartitionInfoMap.clear() } //向对应的 Broker 添加 LeaderAndIsr 请求，请求会被添加到 leaderAndIsrRequestMap 集合中； //并通过 addUpdateMetadataRequestForBrokers() 方法向所有的 Broker 添加这个 Topic-Partition 的 UpdateMatedata 请求， //leader 或 isr 变动时，会向所有 broker 同步这个 Partition 的 metadata 信息，这样可以保证每台 Broker 上都有最新的 metadata 信息。 def addLeaderAndIsrRequestForBrokers(brokerIds: Seq[Int], topic: String, partition: Int, leaderIsrAndControllerEpoch: LeaderIsrAndControllerEpoch, replicas: Seq[Int], isNew: Boolean = false) { val topicPartition = new TopicPartition(topic, partition) //将请求添加到对应的 broker 上 brokerIds.filter(_ >= 0).foreach { brokerId => val result = leaderAndIsrRequestMap.getOrElseUpdate(brokerId, mutable.Map.empty) val alreadyNew = result.get(topicPartition).exists(_.isNew) result.put(topicPartition, new LeaderAndIsrRequest.PartitionState(leaderIsrAndControllerEpoch.controllerEpoch, leaderIsrAndControllerEpoch.leaderAndIsr.leader, leaderIsrAndControllerEpoch.leaderAndIsr.leaderEpoch, leaderIsrAndControllerEpoch.leaderAndIsr.isr.map(Integer.valueOf).asJava, leaderIsrAndControllerEpoch.leaderAndIsr.zkVersion, replicas.map(Integer.valueOf).asJava, isNew || alreadyNew)) } //在更新 LeaderAndIsr 信息时,主题的 metadata 相当于也进行了更新,需要发送这个 topic 的 metadata 给所有存活的 broker addUpdateMetadataRequestForBrokers(controllerContext.liveOrShuttingDownBrokerIds.toSeq, Set(TopicAndPartition(topic, partition))) } //向给定的 Broker 发送某个 Topic Partition 的 StopReplica 请求； def addStopReplicaRequestForBrokers(brokerIds: Seq[Int], topic: String, partition: Int, deletePartition: Boolean, callback: (AbstractResponse, Int) => Unit = null) { brokerIds.filter(b => b >= 0).foreach { brokerId => stopReplicaRequestMap.getOrElseUpdate(brokerId, Seq.empty[StopReplicaRequestInfo]) val v = stopReplicaRequestMap(brokerId) if(callback != null) stopReplicaRequestMap(brokerId) = v :+ StopReplicaRequestInfo(PartitionAndReplica(topic, partition, brokerId), deletePartition, (r: AbstractResponse) => callback(r, brokerId)) else stopReplicaRequestMap(brokerId) = v :+ StopReplicaRequestInfo(PartitionAndReplica(topic, partition, brokerId), deletePartition) } } //向给定的 Broker 发送某一批 Partitions 的 UpdateMetadata 请求。 //首先过滤出要发送的 Partition 列表，如果没有指定要发送 partitions 列表，那么默认就是发送全局的 metadata 信息； //接着将已经标记为删除的 Partition 从上面的列表中移除； //将要发送的 Broker 列表添加到 updateMetadataRequestBrokerSet 集合中； //将前面过滤的 Partition 列表对应的 metadata 信息添加到对应的 updateMetadataRequestPartitionInfoMap 集合中; //将当前设置为删除的所有 Partition 的 metadata 信息也添加到 updateMetadataRequestPartitionInfoMap 集合中，添加前会把其 leader 设置为-2， // 这样 Broker 收到这个 Partition 的 metadata 信息之后就会知道这个 Partition 是设置删除标志。 /** Send UpdateMetadataRequest to the given brokers for the given partitions and partitions that are being deleted */ def addUpdateMetadataRequestForBrokers(brokerIds: Seq[Int], partitions: collection.Set[TopicAndPartition] = Set.empty[TopicAndPartition]) { //将 Topic-Partition 添加到对应的 map 中 def updateMetadataRequestPartitionInfo(partition: TopicAndPartition, beingDeleted: Boolean) { val leaderIsrAndControllerEpochOpt = controllerContext.partitionLeadershipInfo.get(partition) leaderIsrAndControllerEpochOpt match { case Some(l @ LeaderIsrAndControllerEpoch(leaderAndIsr, controllerEpoch)) => val replicas = controllerContext.partitionReplicaAssignment(partition) val offlineReplicas = replicas.filter(!controllerContext.isReplicaOnline(_, partition)) val leaderIsrAndControllerEpoch = if (beingDeleted) { val leaderDuringDelete = LeaderAndIsr.duringDelete(leaderAndIsr.isr) LeaderIsrAndControllerEpoch(leaderDuringDelete, controllerEpoch) } else { l } val partitionStateInfo = new UpdateMetadataRequest.PartitionState(leaderIsrAndControllerEpoch.controllerEpoch, leaderIsrAndControllerEpoch.leaderAndIsr.leader, leaderIsrAndControllerEpoch.leaderAndIsr.leaderEpoch, leaderIsrAndControllerEpoch.leaderAndIsr.isr.map(Integer.valueOf).asJava, leaderIsrAndControllerEpoch.leaderAndIsr.zkVersion, replicas.map(Integer.valueOf).asJava, offlineReplicas.map(Integer.valueOf).asJava) updateMetadataRequestPartitionInfoMap.put(new TopicPartition(partition.topic, partition.partition), partitionStateInfo) case None => info("Leader not yet assigned for partition %s. Skip sending UpdateMetadataRequest.".format(partition)) } } //过滤出要发送的 partition val filteredPartitions = { //Partitions 为空时，就过滤出所有的 topic val givenPartitions = if (partitions.isEmpty) controllerContext.partitionLeadershipInfo.keySet else partitions if (controller.topicDeletionManager.partitionsToBeDeleted.isEmpty) givenPartitions else givenPartitions -- controller.topicDeletionManager.partitionsToBeDeleted } //将 broker 列表更新到要发送的集合中 updateMetadataRequestBrokerSet ++= brokerIds.filter(_ >= 0) //对于要更新 metadata 的 Partition,设置 beingDeleted 为 False filteredPartitions.foreach(partition => updateMetadataRequestPartitionInfo(partition, beingDeleted = false)) //要删除的 Partition 设置 BeingDeleted 为 True controller.topicDeletionManager.partitionsToBeDeleted.foreach(partition => updateMetadataRequestPartitionInfo(partition, beingDeleted = true)) } //发送请求给 broker（只是将对应处理后放入到对应的 queue 中） //此方法将三个集合中的请求发送对应 Broker 的请求队列中，这里简单作一个总结： //从 leaderAndIsrRequestMap 集合中构造相应的 LeaderAndIsr 请求，通过 Controller 的 sendRequest() 方法将请求添加到 Broker 对应的 MessageQueue 中，最后清空 leaderAndIsrRequestMap 集合； //从 updateMetadataRequestPartitionInfoMap 集合中构造相应的 UpdateMetadata 请求，，通过 Controller 的 sendRequest() 方法将请求添加到 Broker 对应的 MessageQueue 中，最后清空 updateMetadataRequestBrokerSet 和 updateMetadataRequestPartitionInfoMap 集合； //从 stopReplicaRequestMap 集合中构造相应的 StopReplica 请求，在构造时会根据是否设置删除标志将要涉及的 Partition 分成两类，构造对应的请求，对于要删除数据的 StopReplica 会设置相应的回调函数，然后通过 Controller 的 sendRequest() 方法将请求添加到 Broker 对应的 MessageQueue 中，最后清空 stopReplicaRequestMap 集合。 //走到这一步，Controller 要发送的请求算是都添加到对应 Broker 的 MessageQueue 中，后台的 RequestSendThread 线程会从这个请求队列中遍历相应的请求，发送给对应的 Broker。 def sendRequestsToBrokers(controllerEpoch: Int) { try { val stateChangeLog = stateChangeLogger.withControllerEpoch(controllerEpoch) val leaderAndIsrRequestVersion: Short = if (controller.config.interBrokerProtocolVersion >= KAFKA_1_0_IV0) 1 else 0 //LeaderAndIsr 请求 leaderAndIsrRequestMap.foreach { case (broker, leaderAndIsrPartitionStates) => leaderAndIsrPartitionStates.foreach { case (topicPartition, state) => val typeOfRequest = if (broker == state.basePartitionState.leader) "become-leader" else "become-follower" stateChangeLog.trace(s"Sending $typeOfRequest LeaderAndIsr request $state to broker $broker for partition $topicPartition") } //leader id 集合 val leaderIds = leaderAndIsrPartitionStates.map(_._2.basePartitionState.leader).toSet val leaders = controllerContext.liveOrShuttingDownBrokers.filter(b => leaderIds.contains(b.id)).map { _.getNode(controller.config.interBrokerListenerName) } //构造 LeaderAndIsr 请求,并添加到对应的 queue 中 val leaderAndIsrRequestBuilder = new LeaderAndIsrRequest.Builder(leaderAndIsrRequestVersion, controllerId, controllerEpoch, leaderAndIsrPartitionStates.asJava, leaders.asJava) controller.sendRequest(broker, ApiKeys.LEADER_AND_ISR, leaderAndIsrRequestBuilder, (r: AbstractResponse) => controller.eventManager.put(controller.LeaderAndIsrResponseReceived(r, broker))) } //清空 leaderAndIsr 集合 leaderAndIsrRequestMap.clear() updateMetadataRequestPartitionInfoMap.foreach { case (tp, partitionState) => stateChangeLog.trace(s"Sending UpdateMetadata request $partitionState to brokers $updateMetadataRequestBrokerSet " + s"for partition $tp") } val partitionStates = Map.empty ++ updateMetadataRequestPartitionInfoMap val updateMetadataRequestVersion: Short = if (controller.config.interBrokerProtocolVersion >= KAFKA_1_0_IV0) 4 else if (controller.config.interBrokerProtocolVersion >= KAFKA_0_10_2_IV0) 3 else if (controller.config.interBrokerProtocolVersion >= KAFKA_0_10_0_IV1) 2 else if (controller.config.interBrokerProtocolVersion >= KAFKA_0_9_0) 1 else 0 //构造 update-metadata 请求 val updateMetadataRequest = { val liveBrokers = if (updateMetadataRequestVersion == 0) { // Version 0 of UpdateMetadataRequest only supports PLAINTEXT. controllerContext.liveOrShuttingDownBrokers.map { broker => val securityProtocol = SecurityProtocol.PLAINTEXT val listenerName = ListenerName.forSecurityProtocol(securityProtocol) val node = broker.getNode(listenerName) val endPoints = Seq(new EndPoint(node.host, node.port, securityProtocol, listenerName)) new UpdateMetadataRequest.Broker(broker.id, endPoints.asJava, broker.rack.orNull) } } else { controllerContext.liveOrShuttingDownBrokers.map { broker => val endPoints = broker.endPoints.map { endPoint => new UpdateMetadataRequest.EndPoint(endPoint.host, endPoint.port, endPoint.securityProtocol, endPoint.listenerName) } new UpdateMetadataRequest.Broker(broker.id, endPoints.asJava, broker.rack.orNull) } } new UpdateMetadataRequest.Builder(updateMetadataRequestVersion, controllerId, controllerEpoch, partitionStates.asJava, liveBrokers.asJava) } // 将请求添加到对应的 queue updateMetadataRequestBrokerSet.foreach { broker => controller.sendRequest(broker, ApiKeys.UPDATE_METADATA, updateMetadataRequest, null) } updateMetadataRequestBrokerSet.clear() updateMetadataRequestPartitionInfoMap.clear() // StopReplica 请求的处理 stopReplicaRequestMap.foreach { case (broker, replicaInfoList) => val stopReplicaWithDelete = replicaInfoList.filter(_.deletePartition).map(_.replica).toSet val stopReplicaWithoutDelete = replicaInfoList.filterNot(_.deletePartition).map(_.replica).toSet debug("The stop replica request (delete = true) sent to broker %d is %s" .format(broker, stopReplicaWithDelete.mkString(","))) debug("The stop replica request (delete = false) sent to broker %d is %s" .format(broker, stopReplicaWithoutDelete.mkString(","))) val (replicasToGroup, replicasToNotGroup) = replicaInfoList.partition(r => !r.deletePartition && r.callback == null) // Send one StopReplicaRequest for all partitions that require neither delete nor callback. This potentially // changes the order in which the requests are sent for the same partitions, but that's OK. val stopReplicaRequest = new StopReplicaRequest.Builder(controllerId, controllerEpoch, false, replicasToGroup.map(r => new TopicPartition(r.replica.topic, r.replica.partition)).toSet.asJava) controller.sendRequest(broker, ApiKeys.STOP_REPLICA, stopReplicaRequest) replicasToNotGroup.foreach { r => val stopReplicaRequest = new StopReplicaRequest.Builder( controllerId, controllerEpoch, r.deletePartition, Set(new TopicPartition(r.replica.topic, r.replica.partition)).asJava) controller.sendRequest(broker, ApiKeys.STOP_REPLICA, stopReplicaRequest, r.callback) } } stopReplicaRequestMap.clear() } catch { case e: Throwable => if (leaderAndIsrRequestMap.nonEmpty) { error("Haven't been able to send leader and isr requests, current state of " + s"the map is $leaderAndIsrRequestMap. Exception message: $e") } if (updateMetadataRequestBrokerSet.nonEmpty) { error(s"Haven't been able to send metadata update requests to brokers $updateMetadataRequestBrokerSet, " + s"current state of the partition info is $updateMetadataRequestPartitionInfoMap. Exception message: $e") } if (stopReplicaRequestMap.nonEmpty) { error("Haven't been able to send stop replica requests, current state of " + s"the map is $stopReplicaRequestMap. Exception message: $e") } throw new IllegalStateException(e) } } } case class ControllerBrokerStateInfo(networkClient: NetworkClient, brokerNode: Node, messageQueue: BlockingQueue[QueueItem], requestSendThread: RequestSendThread, queueSizeGauge: Gauge[Int]) case class StopReplicaRequestInfo(replica: PartitionAndReplica, deletePartition: Boolean, callback: AbstractResponse => Unit = null) class Callbacks private (var stopReplicaResponseCallback: (AbstractResponse, Int) => Unit) object Callbacks { class CallbackBuilder { var stopReplicaResponseCbk: (AbstractResponse, Int) => Unit = null def stopReplicaCallback(cbk: (AbstractResponse, Int) => Unit): CallbackBuilder = { stopReplicaResponseCbk = cbk this } def build: Callbacks = new Callbacks(stopReplicaResponseCbk) } } 