RocketMQ 源码分析 NamesrvController（三）

前言

上一篇在讲到createNamesrvController方法的时候，根据NamesrvConfig和NettyServerConfig对象生成了一个NamesrvController对象，当时并没有deep到该类中，所以这篇来记录一下NamesrvController构造函数的分析。

NamesrvController类

下面是NamesrvController的构造类，这里重点关注的是kvConfigManager、routeInfoManager、brokerHousekeepingService。

public NamesrvController(NamesrvConfig namesrvConfig, NettyServerConfig nettyServerConfig) {
    // Name Server配置
    this.namesrvConfig = namesrvConfig;
    // Netty配置 
    this.nettyServerConfig = nettyServerConfig;
    // KV配置管理
    this.kvConfigManager = new KVConfigManager(this);
    // 路由信息管理 
    this.routeInfoManager = new RouteInfoManager();
    // Broker连接事件处理服务 
    this.brokerHousekeepingService = new BrokerHousekeepingService(this);
    this.configuration = new Configuration(
        log,
        this.namesrvConfig, this.nettyServerConfig
    );
    this.configuration.setStorePathFromConfig(this.namesrvConfig, "configStorePath");
}

kvConfigManager

KVConfigManager作用：

1.加载namesrvController指定的kvConfig配置文件(常为xxx/kvConfig.json)到内存进行读取、增加、删除kvConfig记录。
2.将内存记录的配置,持久化到文件
3.打印所有kvConfig配置

针对上面我有一个疑惑，就是kvConfig.json保存了什么配置呢？服务的一些配置不是在NamesrvConfig和NettyServerConfig中保留了吗？！

KVConfigManager有三个主要成员变量:

public class KVConfigManager {
    private static final InternalLogger log = InternalLoggerFactory.getLogger(LoggerName.NAMESRV_LOGGER_NAME);
    // Name Server主要控制类 
    private final NamesrvController namesrvController;
    // 读写锁 
    private final ReadWriteLock lock = new ReentrantReadWriteLock();
    
    /** 
    * 以命名空间为单位存储的配置文件,存数示例如下: 
    * {"configTable":{"ORDER_TOPIC_CONFIG":{"UnitTest":"test"}}}% 
    * 此处的Namespace为ORDER_TOPIC_CONFIG,暂时不知道Namespace具体的含义 
    */ 
    private final HashMap<String/* Namespace */, HashMap<String/* Key */, String/* Value */>> configTable =
        new HashMap<String, HashMap<String, String>>();

    public KVConfigManager(NamesrvController namesrvController) {
        this.namesrvController = namesrvController;
    }
    ..........省略
}

RouteInfoManager

RouteInfoManager实例中保存了整个消息集群的相关信息，这个是关键类，所以后面对其还需要进一步阅读：

public class RouteInfoManager {
    private static final InternalLogger log = InternalLoggerFactory.getLogger(LoggerName.NAMESRV_LOGGER_NAME);
    private final static long BROKER_CHANNEL_EXPIRED_TIME = 1000 * 60 * 2;
    // 读写锁 
    private final ReadWriteLock lock = new ReentrantReadWriteLock();
    // Topic,以及对应的队列信息 
    private final HashMap<String/* topic */, List<QueueData>> topicQueueTable;
    // 以Broker Name为单位的Broker集合 
    private final HashMap<String/* brokerName */, BrokerData> brokerAddrTable;
    // 集群以及属于该进群的Broker列表 
    private final HashMap<String/* clusterName */, Set<String/* brokerName */>> clusterAddrTable;
    // 存活的Broker地址列表 
    private final HashMap<String/* brokerAddr */, BrokerLiveInfo> brokerLiveTable;
    // Broker对应的Filter Server列表 
    private final HashMap<String/* brokerAddr */, List<String>/* Filter Server */> filterServerTable;

    public RouteInfoManager() {
        this.topicQueueTable = new HashMap<String, List<QueueData>>(1024);
        this.brokerAddrTable = new HashMap<String, BrokerData>(128);
        this.clusterAddrTable = new HashMap<String, Set<String>>(32);
        this.brokerLiveTable = new HashMap<String, BrokerLiveInfo>(256);
        this.filterServerTable = new HashMap<String, List<String>>(256);
    }
    ..........省略
}

BrokerHousekeepingService

该类负责Broker连接事件的处理,实现了ChannelEventListener,主要用来管理RouteInfoManager的brokerLiveTable。BrokerHousekeepingService实现了ChannelEventListener接口, 并且NettyRemotingServer启动时会启动BrokerHousekeepingService。

BrokerHousekeepingService会对连接事件, 连接关闭事件, 异常事件,闲置事件进行处理，进而来判断管理存活的broker。

public class BrokerHousekeepingService implements ChannelEventListener {
    private static final InternalLogger log = InternalLoggerFactory.getLogger(LoggerName.NAMESRV_LOGGER_NAME);
    private final NamesrvController namesrvController;

    public BrokerHousekeepingService(NamesrvController namesrvController) {
        this.namesrvController = namesrvController;
    }

    //连接事件
    @Override
    public void onChannelConnect(String remoteAddr, Channel channel) {
    }

    //关闭事件
    @Override
    public void onChannelClose(String remoteAddr, Channel channel) {
        this.namesrvController.getRouteInfoManager().onChannelDestroy(remoteAddr, channel);
    }

    //异常事件
    @Override
    public void onChannelException(String remoteAddr, Channel channel) {
        this.namesrvController.getRouteInfoManager().onChannelDestroy(remoteAddr, channel);
    }

    //闲置事件
    @Override
    public void onChannelIdle(String remoteAddr, Channel channel) {
        this.namesrvController.getRouteInfoManager().onChannelDestroy(remoteAddr, channel);
    }
}

上面四个方法在监听到事件时，就会触发RouteInfoManager的onChannelDestroy()方法,这个方法比较关键的，所以后面单独抽出来讲。