SpringCloud-Zuul-動態刷新路由機制

註冊監聽器

	@Bean
	public ApplicationListener<ApplicationEvent> zuulRefreshRoutesListener() {
		return new ZuulRefreshListener();
	}

	private static class ZuulRefreshListener
			implements ApplicationListener<ApplicationEvent> {

		@Autowired
		private ZuulHandlerMapping zuulHandlerMapping;

		private HeartbeatMonitor heartbeatMonitor = new HeartbeatMonitor();

		@Override
		public void onApplicationEvent(ApplicationEvent event) {
			if (event instanceof ContextRefreshedEvent
					|| event instanceof RefreshScopeRefreshedEvent
					|| event instanceof RoutesRefreshedEvent
					|| 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 resetIfNeeded(Object value) {
			if (this.heartbeatMonitor.update(value)) {
				reset();
			}
		}

		private void reset() {
			this.zuulHandlerMapping.setDirty(true);
		}

	}

更新路由

	@Override
	protected LinkedHashMap<String, ZuulRoute> locateRoutes() {
		LinkedHashMap<String, ZuulRoute> routesMap = new LinkedHashMap<>();
		routesMap.putAll(super.locateRoutes());
		if (this.discovery != null) {
			Map<String, ZuulRoute> staticServices = new LinkedHashMap<>();
			for (ZuulRoute route : routesMap.values()) {
				String serviceId = route.getServiceId();
				if (serviceId == null) {
					serviceId = route.getId();
				}
				if (serviceId != null) {
					staticServices.put(serviceId, route);
				}
			}
			// Add routes for discovery services by default
			List<String> services = this.discovery.getServices();
			String[] ignored = this.properties.getIgnoredServices()
					.toArray(new String[0]);
			for (String serviceId : services) {
				// Ignore specifically ignored services and those that were manually
				// configured
				String key = "/" + mapRouteToService(serviceId) + "/**";
				if (staticServices.containsKey(serviceId)
						&& staticServices.get(serviceId).getUrl() == null) {
					// Explicitly configured with no URL, cannot be ignored
					// all static routes are already in routesMap
					// Update location using serviceId if location is null
					ZuulRoute staticRoute = staticServices.get(serviceId);
					if (!StringUtils.hasText(staticRoute.getLocation())) {
						staticRoute.setLocation(serviceId);
					}
				}
				if (!PatternMatchUtils.simpleMatch(ignored, serviceId)
						&& !routesMap.containsKey(key)) {
					// Not ignored
					routesMap.put(key, new ZuulRoute(key, serviceId));
				}
			}
		}
		if (routesMap.get(DEFAULT_ROUTE) != null) {
			ZuulRoute defaultRoute = routesMap.get(DEFAULT_ROUTE);
			// Move the defaultServiceId to the end
			routesMap.remove(DEFAULT_ROUTE);
			routesMap.put(DEFAULT_ROUTE, defaultRoute);
		}
		LinkedHashMap<String, ZuulRoute> values = new LinkedHashMap<>();
		for (Entry<String, ZuulRoute> entry : routesMap.entrySet()) {
			String path = entry.getKey();
			// Prepend with slash if not already present.
			if (!path.startsWith("/")) {
				path = "/" + path;
			}
			if (StringUtils.hasText(this.properties.getPrefix())) {
				path = this.properties.getPrefix() + path;
				if (!path.startsWith("/")) {
					path = "/" + path;
				}
			}
			values.put(path, entry.getValue());
		}
		return values;
	}

觸發路由更新

　// org.springframework.cloud.netflix.eureka.CloudEurekaClient#onCacheRefreshed
	@Override
	protected void onCacheRefreshed() {
		super.onCacheRefreshed();

		if (this.cacheRefreshedCount != null) { // might be called during construction and
			// will be null
			long newCount = this.cacheRefreshedCount.incrementAndGet();
			log.trace("onCacheRefreshed called with count: " + newCount);
			this.publisher.publishEvent(new HeartbeatEvent(this, newCount));
		}
	}

	@Override
	// org.springframework.cloud.netflix.eureka.serviceregistry.EurekaAutoServiceRegistration#start
	public void start() {
		// only set the port if the nonSecurePort or securePort is 0 and this.port != 0
		if (this.port.get() != 0) {
			if (this.registration.getNonSecurePort() == 0) {
				this.registration.setNonSecurePort(this.port.get());
			}

			if (this.registration.getSecurePort() == 0 && this.registration.isSecure()) {
				this.registration.setSecurePort(this.port.get());
			}
		}

		// only initialize if nonSecurePort is greater than 0 and it isn't already running
		// because of containerPortInitializer below
		if (!this.running.get() && this.registration.getNonSecurePort() > 0) {

			this.serviceRegistry.register(this.registration);

			this.context.publishEvent(new InstanceRegisteredEvent<>(this,
					this.registration.getInstanceConfig()));
			this.running.set(true);
		}
	}