spring cloud gateway收款定制开发服务下线感知延迟,收款定制开发未及时出现503
收款定制开发本篇算是配合之前的一篇了。收款定制开发整体问题是gateway收款定制开发对下线服务感知延迟,收款定制开发之前那篇文章是从服务收款定制开发角度解决自身注销的问题()。收款定制开发本篇是解决gateway收款定制开发自身发现服务问题。
这种问题大体就集中情况
1 服务端注销未正常运行(这个看一下是否及时删除了节点信息就可以排查出来)
2 服务未及时发现节点的变化(这个可以在debug级别日志验证)
3 服务端和网关服务不互通
1.场景描述
注册中心使用的nacos,客户端版本1.4.1。
gateway版本3.0.1。
nacos服务下线(包含手动点下线和服务正常停机)gateway在短暂几秒内还回继续将流量转发到已下线的服务上导致500。过几秒之后恢复正常,响应码变成503。表面上看,应该是gateway服务没有及时发现服务的下线。
2.分析
日志级别调整到debug,发现通过netty发送的下线通知已经抵达gateway服务。这说明nacos注册中心和spring boot服务通讯和订阅是没问题的。
从转发的入口着手:ReactiveLoadBalancerClientFilter#choose 这个方法就是gateway转发时选择服务的
private Mono<Response<ServiceInstance>> choose(Request<RequestDataContext> lbRequest, String serviceId, Set<LoadBalancerLifecycle> supportedLifecycleProcessors) { ReactorLoadBalancer<ServiceInstance> loadBalancer = this.clientFactory.getInstance(serviceId, ReactorServiceInstanceLoadBalancer.class); if (loadBalancer == null) { throw new NotFoundException("No loadbalancer available for " + serviceId); } supportedLifecycleProcessors.forEach(lifecycle -> lifecycle.onStart(lbRequest)); // 最后是通过ReactorLoadBalancer的实现进行选择 return loadBalancer.choose(lbRequest); }
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ReactorLoadBalancer是负载均衡的接口,提供了两个实现,一个随机获取,一个轮询。
默认是使用轮询实现(RoundRobinLoadBalancer)。
RoundRobinLoadBalancer中选择服务的实现逻辑
public Mono<Response<ServiceInstance>> choose(Request request) { ServiceInstanceListSupplier supplier = serviceInstanceListSupplierProvider .getIfAvailable(NoopServiceInstanceListSupplier::new); // 在这个get方法中返回了可选服务器的集合 return supplier.get(request).next() .map(serviceInstances -> processInstanceResponse(supplier, serviceInstances)); }
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上面那个get的实现是:CachingServiceInstanceListSupplier#CachingServiceInstanceListSupplier这个类中提供的
public CachingServiceInstanceListSupplier(ServiceInstanceListSupplier delegate, CacheManager cacheManager) { super(delegate); this.serviceInstances = CacheFlux.lookup(key -> { // 这里发现有缓存!感觉目的地近了。 Cache cache = cacheManager.getCache(SERVICE_INSTANCE_CACHE_NAME); .... }).then()); }
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2.1定位问题
调试一下看看:
- 服务A启动注册到nacos
- gateway正常将/test/hello转发至服务A
- 在nacos管理端让服务A下线
- 立刻访问不停/test/hello
- 最初几秒内发现gateway还是会把流量打到服务A
- 之后正常响应503
在获取服务集群信息的地方打断点
public CachingServiceInstanceListSupplier(ServiceInstanceListSupplier delegate, CacheManager cacheManager) { super(delegate); this.serviceInstances = CacheFlux.lookup(key -> { // TODO: configurable cache name Cache cache = cacheManager.getCache(SERVICE_INSTANCE_CACHE_NAME); if (cache == null) { if (log.isErrorEnabled()) { log.error("Unable to find cache: " + SERVICE_INSTANCE_CACHE_NAME); } return Mono.empty(); } // 在异常的时间段,这个list还是有信息。集合没内容之后开始响应503 List<ServiceInstance> list = cache.get(key, List.class); if (list == null || list.isEmpty()) { return Mono.empty(); } return Flux.just(list).materialize().collectList(); } ... }
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看来是这个缓存没有及时刷新的原因!后续找了一段时间,没找到刷新缓存的地方就放弃了。还是用笨方法先解决吧
3.解决方案
已经知道了问题所在,想办法解决就是了。
整体思路:在订阅nacos服务变化中进行功能拓展,刷新缓存。
三个类:
SubscribeConfig:进行订阅配置的入口
NacosSubscribe:订阅nacos的实现,用来发布订阅消息
NacosEventListener:消息处理的实现,在这里刷新缓存
先在写个spring.factories
org.springframework.boot.autoconfigure.EnableAutoConfiguration=
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com.dong.gateway.config.SubscribeConfig
SubscribeConfig:
import com.alibaba.cloud.nacos.NacosDiscoveryProperties;import com.alibaba.cloud.nacos.NacosServiceManager;import com.dong.common.core.util.SpringContextHolder;import com.dong.server.gateway.subscribe.NacosSubscribe;import com.dong.server.gateway.subscribe.NacosEventListener;import org.springframework.boot.autoconfigure.AutoConfigureAfter;import org.springframework.cloud.loadbalancer.cache.LoadBalancerCacheManager;import org.springframework.cloud.loadbalancer.config.LoadBalancerCacheAutoConfiguration;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;/** * 首先订阅当前网关关注的服务 * nacos服务更新通知,但是gateway有一套自己的服务缓存列表。每次接到通知更新不及时导致转发到已经下线的服务 * gateway获取缓存参考:org.springframework.cloud.loadbalancer.core.CachingServiceInstanceListSupplier * nacos订阅参考:com.alibaba.cloud.nacos.discovery.NacosWatch#start() * * @Author: dong * @Date: 2021/12/30 10:25 */@Configuration@Import(SpringContextHolder.class)@AutoConfigureAfter(LoadBalancerCacheAutoConfiguration.class)public class SubscribeConfig { @Bean public NacosSubscribe getNacosSubscribe(NacosServiceManager nacosServiceManager, NacosDiscoveryProperties properties){ LoadBalancerCacheManager cacheManager = SpringContextHolder.getBean(LoadBalancerCacheManager.class); return new NacosSubscribe(nacosServiceManager,properties,new NacosEventListener(loadBalancerCacheManager)); }}
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NacosSubscribe
import cn.hutool.core.collection.CollectionUtil;import com.alibaba.cloud.nacos.NacosDiscoveryProperties;import com.alibaba.cloud.nacos.NacosServiceManager;import com.alibaba.nacos.api.naming.NamingService;import lombok.AllArgsConstructor;import lombok.extern.slf4j.Slf4j;import org.springframework.boot.ApplicationArguments;import org.springframework.boot.ApplicationRunner;import org.springframework.cloud.gateway.event.RefreshRoutesEvent;import java.net.URI;import java.util.HashSet;import java.util.List;import java.util.Objects;import java.util.Set;/** * 订阅nacos推送更新事件 * 启动和加载路由时重新订阅 * @Author: dong * @Date: 2021/12/30 15:45 */@Slf4j@AllArgsConstructorpublic class NacosSubscribe implements ApplicationRunner { private NacosServiceManager nacosServiceManager; private NacosDiscoveryProperties properties; private NacosEventListener myEventListener; private Set<String> getRouteServices(){ // TODO 这里返回自己要订阅的服务名称 return new HashSet(); } // 这里监听时间是为了在路由信息修改时候,重新订阅服务的。如果说路由重新加载不会有订阅变动的话,可以去掉@org.springframework.context.event.EventListener({RefreshRoutesEvent.class}) public void subscribe() { NamingService namingService = nacosServiceManager .getNamingService(properties.getNacosProperties()); try { Set<String> services = getRouteServices(); if(CollectionUtil.isNotEmpty(services)){ for (String service : services) { namingService.subscribe(service, properties.getGroup(), null, myEventListener); } } } catch (Exception e) { log.error("namingService subscribe failed, properties:{}", properties, e); } } @Override public void run(ApplicationArguments args) throws Exception { subscribe(); }}
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NacosEventListener
import com.alibaba.cloud.nacos.discovery.NacosServiceDiscovery;import com.alibaba.nacos.api.common.Constants;import com.alibaba.nacos.api.naming.listener.Event;import com.alibaba.nacos.api.naming.listener.EventListener;import com.alibaba.nacos.api.naming.listener.NamingEvent;import com.alibaba.nacos.api.naming.pojo.Instance;import lombok.AllArgsConstructor;import lombok.extern.slf4j.Slf4j;import org.springframework.cache.Cache;import org.springframework.cloud.loadbalancer.cache.LoadBalancerCacheManager;import org.springframework.cloud.loadbalancer.core.CachingServiceInstanceListSupplier;import java.util.List;/** * 处理nacos推送更新事件 * * @Author: dong * @Date: 2021/12/30 16:42 */@Slf4j@AllArgsConstructorpublic class NacosEventListener implements EventListener { private LoadBalancerCacheManager loadBalancerCacheManager; @Override public void onEvent(Event event) { try { if (event instanceof NamingEvent) { Cache cache = loadBalancerCacheManager.getCache(CachingServiceInstanceListSupplier.SERVICE_INSTANCE_CACHE_NAME); if(cache!=null){ NamingEvent namingEvent = ((NamingEvent) event); String serviceName = namingEvent.getServiceName(); String[] split = serviceName.split(Constants.SERVICE_INFO_SPLITER); String serviceId = split[1]; log.debug("收到更新服务消息:{}",serviceId); List<Instance> instances = namingEvent.getInstances(); cache.put(serviceId, NacosServiceDiscovery.hostToServiceInstanceList(instances,serviceId)); } } }catch (Exception e){ log.error("处理nacos推送失败!",e); } }}
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20220620更新:SubscribeConfig中用到的工具类
import lombok.extern.slf4j.Slf4j;import org.springframework.beans.factory.DisposableBean;import org.springframework.context.ApplicationContext;import org.springframework.context.ApplicationContextAware;import org.springframework.context.annotation.Lazy;/** * Spring 工具类 * * @Author: dong * @Date: 2021/8/10 10:27 */@Slf4j@Lazy(false)public class SpringContextHolder implements ApplicationContextAware, DisposableBean { private static ApplicationContext applicationContext = null; @Override public void setApplicationContext(ApplicationContext applicationContext) { SpringContextHolder.applicationContext = applicationContext; } public static <T> T getBean(Class<T> requiredType) { return applicationContext.getBean(requiredType); } public static void clearHolder() { if (log.isDebugEnabled()) { log.debug("清除SpringContextHolder中的ApplicationContext:" + applicationContext); } applicationContext = null; } @Override public void destroy() { SpringContextHolder.clearHolder(); }}
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