08、Sentinel实战：ClusterServerConfigManager-程序员江小北

声明了三个属性，为属性添加监听器

    /**
     * Property for cluster server global transport configuration.
     */
    private static SentinelProperty<ServerTransportConfig> transportConfigProperty = new DynamicSentinelProperty<>();
    /**
     * Property for cluster server namespace set.
     */
    private static SentinelProperty<Set<String>> namespaceSetProperty = new DynamicSentinelProperty<>();
    /**
     * Property for cluster server global flow control configuration.
     */
    private static SentinelProperty<ServerFlowConfig> globalFlowProperty = new DynamicSentinelProperty<>();

    private static final PropertyListener<ServerTransportConfig> TRANSPORT_PROPERTY_LISTENER
        = new ServerGlobalTransportPropertyListener();
    private static final PropertyListener<ServerFlowConfig> GLOBAL_FLOW_PROPERTY_LISTENER
        = new ServerGlobalFlowPropertyListener();
    private static final PropertyListener<Set<String>> NAMESPACE_SET_PROPERTY_LISTENER
        = new ServerNamespaceSetPropertyListener();

    static {
        transportConfigProperty.addListener(TRANSPORT_PROPERTY_LISTENER);
        globalFlowProperty.addListener(GLOBAL_FLOW_PROPERTY_LISTENER);
        namespaceSetProperty.addListener(NAMESPACE_SET_PROPERTY_LISTENER);
    }

ServerGlobalTransportPropertyListener

监听server的端口配置

当我们修改端口，保存后，sentinel后台会调用服务的sentinel-api /cluster/server/modifyTransportConfig

进而触发transportConfigProperty的改变，进而再触发ServerGlobalTransportPropertyListener的configUpdate方法，最后会重启token-server到新的端口

com.alibaba.csp.sentinel.cluster.server.config.ClusterServerConfigManager.ServerGlobalTransportPropertyListener#configUpdate

        @Override
        public void configUpdate(ServerTransportConfig config) {
            applyConfig(config);
        }

com.alibaba.csp.sentinel.cluster.server.config.ClusterServerConfigManager.ServerGlobalTransportPropertyListener#applyConfig

        private synchronized void applyConfig(ServerTransportConfig config) {
            if (!isValidTransportConfig(config)) {
                RecordLog.warn(
                    "[ClusterServerConfigManager] Invalid cluster server transport config, ignoring: {}", config);
                return;
            }
            RecordLog.info("[ClusterServerConfigManager] Updating new server transport config: {}", config);
            if (config.getIdleSeconds() != idleSeconds) {
                idleSeconds = config.getIdleSeconds();
            }
            //!!!
            updateTokenServer(config);
        }

com.alibaba.csp.sentinel.cluster.server.config.ClusterServerConfigManager#updateTokenServer

    private static void updateTokenServer(ServerTransportConfig config) {
        int newPort = config.getPort();
        AssertUtil.isTrue(newPort > 0, "token server port should be valid (positive)");
        if (newPort == port) {
            return;
        }
        ClusterServerConfigManager.port = newPort;

        for (ServerTransportConfigObserver observer : TRANSPORT_CONFIG_OBSERVERS) {
            //!!!
            observer.onTransportConfigChange(config);
        }
    }

com.alibaba.csp.sentinel.cluster.server.SentinelDefaultTokenServer#changeServerConfig

    private synchronized void changeServerConfig(ServerTransportConfig config) {
        if (config == null || config.getPort() <= 0) {
            return;
        }
        int newPort = config.getPort();
        if (newPort == port) {
            return;
        }
        try {
            if (server != null) {
                stopServer();
            }
            this.server = new NettyTransportServer(newPort);
            this.port = newPort;
            startServerIfScheduled();
        } catch (Exception ex) {
            RecordLog.warn("[SentinelDefaultTokenServer] Failed to apply modification to token server", ex);
        }
    }

ServerGlobalFlowPropertyListener

监听token-server最大允许qps的改变

当我们修改最大允许QPS并保存后，sentinel后台会调用服务的token-api cluster/server/modifyFlowConfig

进而触发globalFlowProperty的改变，进而再触发ServerGlobalFlowPropertyListener的configUpdate方法

ServerNamespaceSetPropertyListener

待研究