路由刷新-Nacos

1 Nacos动态刷新

不需要开发，基于文件刷新机制就可以满足

• 增加Nacos的POM依赖

        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
        </dependency>

• bootstrap.properties配置Nacos Config

  spring.application.name=gateway-inner
  spring.cloud.nacos.discovery.server-addr=127.0.0.1:8848
  spring.cloud.nacos.config.server-addr=127.0.0.1:8848
  spring.cloud.nacos.config.group=DEFAULT_GROUP
  

• Nacos 控制台添加项目属性文件配置

  2 原理

  2.1 流程图

  

  2.2 源码分析

  2.2.1 文件更新监听

• com.alibaba.nacos.client.config.impl.ClientWorker

• com.alibaba.nacos.client.config.impl.CacheData

  // Nacos客户端长连接
  public ClientWorker(final HttpAgent agent, final ConfigFilterChainManager configFilterChainManager,
            final Properties properties) {
        this.agent = agent;
        this.configFilterChainManager = configFilterChainManager;
  
        this.executor = Executors.newScheduledThreadPool(1, new ThreadFactory() {
            @Override
            public Thread newThread(Runnable r) {
                Thread t = new Thread(r);
                t.setName("com.alibaba.nacos.client.Worker." + agent.getName());
                t.setDaemon(true);
                return t;
            }
        });
        // 10毫秒检测配置更新
        this.executor.scheduleWithFixedDelay(new Runnable() {
            @Override
            public void run() {
                try {
                    checkConfigInfo();
                } catch (Throwable e) {
                    LOGGER.error("[" + agent.getName() + "] [sub-check] rotate check error", e);
                }
            }
        }, 1L, 10L, TimeUnit.MILLISECONDS);
    }
  

  class LongPollingRunnable implements Runnable {
        private final int taskId;
        public LongPollingRunnable(int taskId) {
            this.taskId = taskId;
        }
        @Override
        public void run() {
  
            List<CacheData> cacheDatas = new ArrayList<CacheData>();
            List<String> inInitializingCacheList = new ArrayList<String>();
            try { 
                // 1：检查服务配置
                List<String> changedGroupKeys = checkUpdateDataIds(cacheDatas, inInitializingCacheList);
                if (!CollectionUtils.isEmpty(changedGroupKeys)) {
                    LOGGER.info("get changedGroupKeys:" + changedGroupKeys);
                }
                for (String groupKey : changedGroupKeys) {
                    try {
                        // 2：获取服务配置
                        ConfigResponse response = getServerConfig(dataId, group, tenant, 3000L);
                    }
                }
                for (CacheData cacheData : cacheDatas) {
                    if (!cacheData.isInitializing() || inInitializingCacheList
                            .contains(GroupKey.getKeyTenant(cacheData.dataId, cacheData.group, cacheData.tenant))) {
                        // 3：检查监听
                        cacheData.checkListenerMd5();
                        cacheData.setInitializing(false);
                    }
                }
            } 
        }
    }
  

  2.2.2 发布RefreshEvent事件

• com.alibaba.cloud.nacos.refresh.NacosContextRefresher

  ·    private void registerNacosListener(final String groupKey, final String dataKey) {
        String key = NacosPropertySourceRepository.getMapKey(dataKey, groupKey);
        Listener listener = listenerMap.computeIfAbsent(key,
                lst -> new AbstractSharedListener() {
                    @Override
                    public void innerReceive(String dataId, String group,
                            String configInfo) {
                        refreshCountIncrement();
                        nacosRefreshHistory.addRefreshRecord(dataId, group, configInfo);
                        applicationContext.publishEvent(
                                new RefreshEvent(this, null, "Refresh Nacos config"));
                    }
                });
        try {
            configService.addListener(dataKey, groupKey, listener);
        }
    }
  

  2.2.3 处理RefreshEvent事件发布RefreshScopeRefreshedEvent事件

• org.springframework.cloud.endpoint.event.RefreshEventListener

    @Override
    public void onApplicationEvent(ApplicationEvent event) {
        if (event instanceof ApplicationReadyEvent) {
            handle((ApplicationReadyEvent) event);
        }
        else if (event instanceof RefreshEvent) {
            handle((RefreshEvent) event);
        }
    }
    public void handle(RefreshEvent event) {
        if (this.ready.get()) { // don't handle events before app is ready
            Set<String> keys = this.refresh.refresh();
        }
    }
  

• org.springframework.cloud.context.refresh.ContextRefresher

    public synchronized Set<String> refresh() {
        Set<String> keys = refreshEnvironment();
        this.scope.refreshAll();
        return keys;
    }
    public void refreshAll() {
        super.destroy();
        this.context.publishEvent(new RefreshScopeRefreshedEvent());
    }
  

  2.2.4 处理RefreshScopeRefreshedEvent发布RefreshRoutesEvent

• org.springframework.cloud.gateway.route.RouteRefreshListener

    @Override
    public void onApplicationEvent(ApplicationEvent event) {
        if (event instanceof ContextRefreshedEvent) {
            ContextRefreshedEvent refreshedEvent = (ContextRefreshedEvent) event;
            if (!WebServerApplicationContext.hasServerNamespace(
                    refreshedEvent.getApplicationContext(), "management")) {
                reset();
            }
        }
        else if (event instanceof RefreshScopeRefreshedEvent
                || event instanceof InstanceRegisteredEvent) {
            reset();
        }
        else if (event instanceof ParentHeartbeatEvent) {
            ParentHeartbeatEvent e = (ParentHeartbeatEvent) event;
            resetIfNeeded(e.getValue());
        }
        else if (event instanceof HeartbeatEvent) {
            HeartbeatEvent e = (HeartbeatEvent) event;
            resetIfNeeded(e.getValue());
        }
    }
    private void reset() {
        this.publisher.publishEvent(new RefreshRoutesEvent(this));
    }
  

  2.2.5 处理RefreshRoutesEvent

• org.springframework.cloud.gateway.route.CachingRouteDefinitionLocator

• org.springframework.cloud.gateway.route.CachingRouteLocator