NameServer：在系统中是做命名服务，更新和发现 broker服务。
Broker-Master：broker 消息主机服务器。
Broker-Slave： broker 消息从机服务器。
Producer： 消息生产者。
Consumer： 消息消费者。
rocketmq的几个核心的模块，而对于每个模块都是单独的jvm进程，我们看到上面的架构图的时候，那些箭头就是rocketmq的rpc调用，下面我们来看看rocketmq的rpc是如果进行封装实现的。
说明： rocketmq系列都将会以rocketmq-4.1.0-incubating进行介绍。
RocketMQ通信组件先排除Master、Slave直接通过原生的nio进行调用，其他通讯都是基于netty-all-4.0.36.Final以及RocketMQ自定义协议进行通讯的。
网络协议定义如下我们来看看header data里面的数据定义：
code对于Request来说就是RequestCode类里面的常量信息：
说明：公众号【匠心零度】回复：rocketmq，可获得基于rocketmq4.1.0加详细中文代码注释 。
public class RequestCode { // Broker 发送消息 public static final int SEND_MESSAGE = 10; // Broker 订阅消息 public static final int PULL_MESSAGE = 11; // Broker 查询消息 public static final int QUERY_MESSAGE = 12; // Broker 查询Broker Offset public static final int QUERY_BROKER_OFFSET = 13; // Broker 查询Consumer Offset public static final int QUERY_CONSUMER_OFFSET = 14; // Broker 更新Consumer Offset public static final int UPDATE_CONSUMER_OFFSET = 15; // Broker 更新或者增加一个Topic public static final int UPDATE_AND_CREATE_TOPIC = 17; // Broker 获取所有Topic的配置（Slave和Namesrv都会向Master请求此配置） public static final int GET_ALL_TOPIC_CONFIG = 21; // Broker 获取所有Topic配置（Slave和Namesrv都会向Master请求此配置 public static final int GET_TOPIC_CONFIG_LIST = 22; // Broker 获取所有Topic名称列表 public static final int GET_TOPIC_NAME_LIST = 23; // Broker 更新Broker上的配置 public static final int UPDATE_BROKER_CONFIG = 25; // Broker 获取Broker上的配置 public static final int GET_BROKER_CONFIG = 26; // Broker 触发Broker删除文件 public static final int TRIGGER_DELETE_FILES = 27; // Broker 获取Broker运行时信息 public static final int GET_BROKER_RUNTIME_INFO = 28; // Broker 根据时间查询队列的Offset public static final int SEARCH_OFFSET_BY_TIMESTAMP = 29; // Broker 查询队列最大Offset public static final int GET_MAX_OFFSET = 30; // Broker 查询队列最小Offset public static final int GET_MIN_OFFSET = 31; // Broker 查询队列最早消息对应时间 public static final int GET_EARLIEST_MSG_STORETIME = 32; // Broker 根据消息ID来查询消息 public static final int VIEW_MESSAGE_BY_ID = 33; // Broker Client向Client发送心跳，并注册自身 public static final int HEART_BEAT = 34; // Broker Client注销 public static final int UNREGISTER_CLIENT = 35; // Broker Consumer将处理不了的消息发回服务器 public static final int CONSUMER_SEND_MSG_BACK = 36; // Broker Commit或者Rollback事务 public static final int END_TRANSACTION = 37; // Broker 获取ConsumerId列表通过GroupName public static final int GET_CONSUMER_LIST_BY_GROUP = 38; // Broker 主动向Producer回查事务状态 public static final int CHECK_TRANSACTION_STATE = 39; // Broker Broker通知Consumer列表变化 public static final int NOTIFY_CONSUMER_IDS_CHANGED = 40; // Broker Consumer向Master锁定队列 public static final int LOCK_BATCH_MQ = 41; // Broker Consumer向Master解锁队列 public static final int UNLOCK_BATCH_MQ = 42; // Broker 获取所有Consumer Offset public static final int GET_ALL_CONSUMER_OFFSET = 43; // Broker 获取所有定时进度 public static final int GET_ALL_DELAY_OFFSET = 45; public static final int CHECK_CLIENT_CONFIG = 46; // Namesrv 向Namesrv追加KV配置 public static final int PUT_KV_CONFIG = 100; // Namesrv 从Namesrv获取KV配置 public static final int GET_KV_CONFIG = 101; // Namesrv 从Namesrv获取KV配置 public static final int DELETE_KV_CONFIG = 102; // Namesrv 注册一个Broker，数据都是持久化的，如果存在则覆盖配置 public static final int REGISTER_BROKER = 103; // Namesrv 卸载一个Broker，数据都是持久化的 public static final int UNREGISTER_BROKER = 104; // Namesrv 根据Topic获取Broker Name、队列数(包含读队列与写队列) public static final int GET_ROUTEINTO_BY_TOPIC = 105; // Namesrv 获取注册到Name Server的所有Broker集群信息 public static final int GET_BROKER_CLUSTER_INFO = 106; public static final int UPDATE_AND_CREATE_SUBSCRIPTIONGROUP = 200; public static final int GET_ALL_SUBSCRIPTIONGROUP_CONFIG = 201; public static final int GET_TOPIC_STATS_INFO = 202; public static final int GET_CONSUMER_CONNECTION_LIST = 203; public static final int GET_PRODUCER_CONNECTION_LIST = 204; public static final int WIPE_WRITE_PERM_OF_BROKER = 205; // 从Name Server获取完整Topic列表 public static final int GET_ALL_TOPIC_LIST_FROM_NAMESERVER = 206; // 从Broker删除订阅组 public static final int DELETE_SUBSCRIPTIONGROUP = 207; // 从Broker获取消费状态（进度） public static final int GET_CONSUME_STATS = 208; // Suspend Consumer消费过程 public static final int SUSPEND_CONSUMER = 209; // Resume Consumer消费过程 public static final int RESUME_CONSUMER = 210; // 重置Consumer Offset public static final int RESET_CONSUMER_OFFSET_IN_CONSUMER = 211; // 重置Consumer Offset public static final int RESET_CONSUMER_OFFSET_IN_BROKER = 212; // 调整Consumer线程池数量 public static final int ADJUST_CONSUMER_THREAD_POOL = 213; // 查询消息被哪些消费组消费 public static final int WHO_CONSUME_THE_MESSAGE = 214; // 从Broker删除Topic配置 public static final int DELETE_TOPIC_IN_BROKER = 215; // 从Namesrv删除Topic配置 public static final int DELETE_TOPIC_IN_NAMESRV = 216; // 通过NameSpace获取所有的KV List public static final int GET_KVLIST_BY_NAMESPACE = 219; // offset 重置 public static final int RESET_CONSUMER_CLIENT_OFFSET = 220; // 客户端订阅消息 public static final int GET_CONSUMER_STATUS_FROM_CLIENT = 221; // 通知 broker 调用 offset 重置处理 public static final int INVOKE_BROKER_TO_RESET_OFFSET = 222; // 通知 broker 调用客户端订阅消息处理 public static final int INVOKE_BROKER_TO_GET_CONSUMER_STATUS = 223; // Broker 查询topic被谁消费 public static final int QUERY_TOPIC_CONSUME_BY_WHO = 300; // 获取指定集群下的所有 topic public static final int GET_TOPICS_BY_CLUSTER = 224; // 向Broker注册Filter Server public static final int REGISTER_FILTER_SERVER = 301; // 向Filter Server注册Class public static final int REGISTER_MESSAGE_FILTER_CLASS = 302; // 根据 topic 和 group 获取消息的时间跨度 public static final int QUERY_CONSUME_TIME_SPAN = 303; // 获取所有系统内置 Topic 列表 public static final int GET_SYSTEM_TOPIC_LIST_FROM_NS = 304; public static final int GET_SYSTEM_TOPIC_LIST_FROM_BROKER = 305; // 清理失效队列 public static final int CLEAN_EXPIRED_CONSUMEQUEUE = 306; // 通过Broker查询Consumer内存数据 public static final int GET_CONSUMER_RUNNING_INFO = 307; // 查找被修正 offset (转发组件） public static final int QUERY_CORRECTION_OFFSET = 308; // 通过Broker直接向某个Consumer发送一条消息，并立刻消费，返回结果给broker，再返回给调用方 public static final int CONSUME_MESSAGE_DIRECTLY = 309; // Broker 发送消息，优化网络数据包 public static final int SEND_MESSAGE_V2 = 310; // 单元化相关 topic public static final int GET_UNIT_TOPIC_LIST = 311; // 获取含有单元化订阅组的 Topic 列表 public static final int GET_HAS_UNIT_SUB_TOPIC_LIST = 312; // 获取含有单元化订阅组的非单元化 Topic 列表 public static final int GET_HAS_UNIT_SUB_UNUNIT_TOPIC_LIST = 313; // 克隆某一个组的消费进度到新的组 public static final int CLONE_GROUP_OFFSET = 314; // 查看Broker上的各种统计信息 public static final int VIEW_BROKER_STATS_DATA = 315; public static final int CLEAN_UNUSED_TOPIC = 316; public static final int GET_BROKER_CONSUME_STATS = 317; /** * update the config of name server */ public static final int UPDATE_NAMESRV_CONFIG = 318; /** * get config from name server */ public static final int GET_NAMESRV_CONFIG = 319; public static final int SEND_BATCH_MESSAGE = 320; public static final int QUERY_CONSUME_QUEUE = 321; }