Kafka核心源码解析 - KafkaApis源码解析

KafkaApis负责处理所有请求，转发到相应到方法

1.KafkaApis初始化

/* start processing requests */
apis = new KafkaApis(socketServer.requestChannel, replicaManager, adminManager, groupCoordinator, transactionCoordinator,
          kafkaController, zkClient, config.brokerId, config, metadataCache, metrics, authorizer, quotaManagers,
          fetchManager, brokerTopicStats, clusterId, time, tokenManager)

2.KafkaApis处理转发请求

客户端与broker交互、broker之间的所有交互请求全部都会经过此方法进行相应的转发处理。

/**
   * Top-level method that handles all requests and multiplexes to the right api
   */
  def handle(request: RequestChannel.Request) {
    
    
    try {
    
    
      trace(s"Handling request:${request.requestDesc(true)} from connection ${request.context.connectionId};" +
        s"securityProtocol:${request.context.securityProtocol},principal:${request.context.principal}")
      request.header.apiKey match {
    
    
        case ApiKeys.PRODUCE => handleProduceRequest(request)//数据生产请求
        case ApiKeys.FETCH => handleFetchRequest(request)//1）follower从leader抓取数据请求；2）消费者从broker消费数据请求；
        case ApiKeys.LIST_OFFSETS => handleListOffsetRequest(request)
        case ApiKeys.METADATA => handleTopicMetadataRequest(request)
        case ApiKeys.LEADER_AND_ISR => handleLeaderAndIsrRequest(request)//处理topic的partition的leader和isr变更请求；
        case ApiKeys.STOP_REPLICA => handleStopReplicaRequest(request)//处理停止副本请求
        case ApiKeys.UPDATE_METADATA => handleUpdateMetadataRequest(request)//更新元数据请求
        case ApiKeys.CONTROLLED_SHUTDOWN => handleControlledShutdownRequest(request)//处理controller的shutdown请求；
        case ApiKeys.OFFSET_COMMIT => handleOffsetCommitRequest(request)
        case ApiKeys.OFFSET_FETCH => handleOffsetFetchRequest(request)
        case ApiKeys.FIND_COORDINATOR => handleFindCoordinatorRequest(request)
        case ApiKeys.JOIN_GROUP => handleJoinGroupRequest(request)
        case ApiKeys.HEARTBEAT => handleHeartbeatRequest(request)
        case ApiKeys.LEAVE_GROUP => handleLeaveGroupRequest(request)
        case ApiKeys.SYNC_GROUP => handleSyncGroupRequest(request)
        case ApiKeys.DESCRIBE_GROUPS => handleDescribeGroupRequest(request)
        case ApiKeys.LIST_GROUPS => handleListGroupsRequest(request)
        case ApiKeys.SASL_HANDSHAKE => handleSaslHandshakeRequest(request)
        case ApiKeys.API_VERSIONS => handleApiVersionsRequest(request)
        case ApiKeys.CREATE_TOPICS => handleCreateTopicsRequest(request)
        case ApiKeys.DELETE_TOPICS => handleDeleteTopicsRequest(request)
        case ApiKeys.DELETE_RECORDS => handleDeleteRecordsRequest(request)
        case ApiKeys.INIT_PRODUCER_ID => handleInitProducerIdRequest(request)
        case ApiKeys.OFFSET_FOR_LEADER_EPOCH => handleOffsetForLeaderEpochRequest(request)
        case ApiKeys.ADD_PARTITIONS_TO_TXN => handleAddPartitionToTxnRequest(request)
        case ApiKeys.ADD_OFFSETS_TO_TXN => handleAddOffsetsToTxnRequest(request)
        case ApiKeys.END_TXN => handleEndTxnRequest(request)
        case ApiKeys.WRITE_TXN_MARKERS => handleWriteTxnMarkersRequest(request)
        case ApiKeys.TXN_OFFSET_COMMIT => handleTxnOffsetCommitRequest(request)
        case ApiKeys.DESCRIBE_ACLS => handleDescribeAcls(request)
        case ApiKeys.CREATE_ACLS => handleCreateAcls(request)
        case ApiKeys.DELETE_ACLS => handleDeleteAcls(request)
        case ApiKeys.ALTER_CONFIGS => handleAlterConfigsRequest(request)
        case ApiKeys.DESCRIBE_CONFIGS => handleDescribeConfigsRequest(request)
        case ApiKeys.ALTER_REPLICA_LOG_DIRS => handleAlterReplicaLogDirsRequest(request)
        case ApiKeys.DESCRIBE_LOG_DIRS => handleDescribeLogDirsRequest(request)
        case ApiKeys.SASL_AUTHENTICATE => handleSaslAuthenticateRequest(request)
        case ApiKeys.CREATE_PARTITIONS => handleCreatePartitionsRequest(request)
        case ApiKeys.CREATE_DELEGATION_TOKEN => handleCreateTokenRequest(request)
        case ApiKeys.RENEW_DELEGATION_TOKEN => handleRenewTokenRequest(request)
        case ApiKeys.EXPIRE_DELEGATION_TOKEN => handleExpireTokenRequest(request)
        case ApiKeys.DESCRIBE_DELEGATION_TOKEN => handleDescribeTokensRequest(request)
        case ApiKeys.DELETE_GROUPS => handleDeleteGroupsRequest(request)
      }
    } catch {
    
    
      case e: FatalExitError => throw e
      case e: Throwable => handleError(request, e)
    } finally {
    
    
      request.apiLocalCompleteTimeNanos = time.nanoseconds
    }
  }