Nacos 配置变更逻辑

• LongPollingService

public LongPollingService() {
        allSubs = new ConcurrentLinkedQueue<ClientLongPolling>();
        
        ConfigExecutor.scheduleLongPolling(new StatTask(), 0L, 10L, TimeUnit.SECONDS);
        
        // Register LocalDataChangeEvent to NotifyCenter.
        NotifyCenter.registerToPublisher(LocalDataChangeEvent.class, NotifyCenter.ringBufferSize);
        
        // Register A Subscriber to subscribe LocalDataChangeEvent.
        NotifyCenter.registerSubscriber(new Subscriber() {
            
            @Override
            public void onEvent(Event event) {
                if (isFixedPolling()) {
                    // Ignore.
                } else {
                    if (event instanceof LocalDataChangeEvent) {
                        LocalDataChangeEvent evt = (LocalDataChangeEvent) event;
                        ConfigExecutor.executeLongPolling(new DataChangeTask(evt.groupKey, evt.isBeta, evt.betaIps));
                    }
                }
            }
            
            @Override
            public Class<? extends Event> subscribeType() {
                return LocalDataChangeEvent.class;
            }
        });
        
    }

构造中分为定时轮训和LocalDataChangeEvent两种方式.

ConfigController. publishConfig -> NotifyCenter.publishEvent()->
发布了时间后 1. 同步其他集群节点 2. 出发了LocalDataChangeEvent，开启任务，提前generatel响应了长轮训的的http请求。 返回结果，相当于http主动的推送了 过来.

• ConfigController
  LongPollingService ClientWorker ConfigService ConfigExecutor

详情看fox老师的笔记.

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Nacos配置中心源码分析.jpg