重庆手机网站推广资料,python基础教程第三版,贺岁币在建设银行那个网站预约,今天最新生猪价格SpringCloud Gateway默认不支持将请求路由到一个服务的多个端口 本文将结合Gateway的处理流程#xff0c;提供一些解决思路 需求背景
公司有一个IM项目#xff0c;对外暴露了两个端口8081和8082#xff0c;8081是springboot启动使用的端口#xff0c;对外提供一些http接口… SpringCloud Gateway默认不支持将请求路由到一个服务的多个端口 本文将结合Gateway的处理流程提供一些解决思路 需求背景
公司有一个IM项目对外暴露了两个端口8081和80828081是springboot启动使用的端口对外提供一些http接口如获取聊天群组成员列表等相关配置如下
spring: application: name: im
server:port: 8081servlet:context-path: /im8082是内部启动了一个netty服务器处理websocket请求实现即时通讯
......
......
pipeline.addLast(new WebSocketServerProtocolHandler(/ws));
......
......
bootstrap.bind(8082).sync();以本地环境为例直连IM项目的请求地址如下
http://localhost:8081/im/*** 请求http接口 ws://localhost:8082/ws进行websocket协议升级
项目组希望客户端能统一走网关实现对这两种接口的调用
问题描述
网关使用springcloud gateway监听端口8080注册中心使用nacos 正常情况下gateway根据服务名转发配置如下 - id: im_routeuri: lb://impredicates:- Path/im/**访问网关http://localhost:8080/im/**即可将请求转发到IM服务 同理我们希望访问网关ws://localhost:8080/ws也能转发到IM的netty服务器
一般情况下如果要通过gateway转发websocket请求我们需要做如下配置 - id: im_ws_routeuri: lb:ws://impredicates:- Path/ws/**但实际上lb这个schema告诉gateway要走负载gateway转发的时候会到nacos拉取im的服务清单将其替换为 ip 端口而nacos上注册的是springboot项目的端口也就是8081所以想转发到IM的8082上默认是没办法利用gateway的服务发现机制的只能直接配置服务的ip地址如下 - id: im_ws_routeuri: ws://localhost:8082predicates:- Path/ws不过这样也就失去使用网关的意义了
寻找思路
先观察下gateway转发的流程找到DispatcherHandler的handle方法 Overridepublic MonoVoid handle(ServerWebExchange exchange) {if (this.handlerMappings null) {return createNotFoundError();}if (CorsUtils.isPreFlightRequest(exchange.getRequest())) {return handlePreFlight(exchange);}return Flux.fromIterable(this.handlerMappings).concatMap(mapping - mapping.getHandler(exchange)).next().switchIfEmpty(createNotFoundError()).onErrorResume(ex - handleDispatchError(exchange, ex)).flatMap(handler - handleRequestWith(exchange, handler));}首先遍历内部的HandlerMapping依次调用其getHandler方法寻找能处理当前请求的Handler
HandlerMapping共有四个一般来说我们配置了上述的路由会在第三个RoutePredicateHandlerMapping返回一个Handler
Handler类型为FilteringWebHandler其中包含了一组Filter
找到Handler后在DispatcherHandler # handle方法的最后一行调了handleRequestWith方法 private MonoVoid handleRequestWith(ServerWebExchange exchange, Object handler) {if (ObjectUtils.nullSafeEquals(exchange.getResponse().getStatusCode(), HttpStatus.FORBIDDEN)) {return Mono.empty(); // CORS rejection}if (this.handlerAdapters ! null) {for (HandlerAdapter adapter : this.handlerAdapters) {if (adapter.supports(handler)) {return adapter.handle(exchange, handler).flatMap(result - handleResult(exchange, result));}}}return Mono.error(new IllegalStateException(No HandlerAdapter: handler));}然后遍历了HandlerAdapter一共有四个
这里起作用的是最后一个SimpleHandlerAdapter进入其handle方法 Overridepublic MonoHandlerResult handle(ServerWebExchange exchange, Object handler) {WebHandler webHandler (WebHandler) handler;MonoVoid mono webHandler.handle(exchange);return mono.then(Mono.empty());}调用了上面找到Handler的handle方法 Overridepublic MonoVoid handle(ServerWebExchange exchange) {Route route exchange.getRequiredAttribute(GATEWAY_ROUTE_ATTR);ListGatewayFilter gatewayFilters route.getFilters();ListGatewayFilter combined new ArrayList(this.globalFilters);combined.addAll(gatewayFilters);// TODO: needed or cached?AnnotationAwareOrderComparator.sort(combined);if (logger.isDebugEnabled()) {logger.debug(Sorted gatewayFilterFactories: combined);}return new DefaultGatewayFilterChain(combined).filter(exchange);}最后filter方法依次执行了其中的Filter Overridepublic MonoVoid filter(ServerWebExchange exchange) {return Mono.defer(() - {if (this.index filters.size()) {GatewayFilter filter filters.get(this.index);DefaultGatewayFilterChain chain new DefaultGatewayFilterChain(this, this.index 1);return filter.filter(exchange, chain);}else {return Mono.empty(); // complete}});}}在这些Filter中有一个ReactiveLoadBalancerClientFilter会完成从nacos拉取服务清单替换请求地址的任务
看下它的filter方法 Overridepublic MonoVoid filter(ServerWebExchange exchange, GatewayFilterChain chain) {URI url exchange.getAttribute(GATEWAY_REQUEST_URL_ATTR);String schemePrefix exchange.getAttribute(GATEWAY_SCHEME_PREFIX_ATTR);if (url null || (!lb.equals(url.getScheme()) !lb.equals(schemePrefix))) {return chain.filter(exchange);}// preserve the original urladdOriginalRequestUrl(exchange, url);if (log.isTraceEnabled()) {log.trace(ReactiveLoadBalancerClientFilter.class.getSimpleName() url before: url);}URI requestUri exchange.getAttribute(GATEWAY_REQUEST_URL_ATTR);String serviceId requestUri.getHost();SetLoadBalancerLifecycle supportedLifecycleProcessors LoadBalancerLifecycleValidator.getSupportedLifecycleProcessors(clientFactory.getInstances(serviceId, LoadBalancerLifecycle.class),RequestDataContext.class, ResponseData.class, ServiceInstance.class);DefaultRequestRequestDataContext lbRequest new DefaultRequest(new RequestDataContext(new RequestData(exchange.getRequest()), getHint(serviceId)));return choose(lbRequest, serviceId, supportedLifecycleProcessors).doOnNext(response - {if (!response.hasServer()) {supportedLifecycleProcessors.forEach(lifecycle - lifecycle.onComplete(new CompletionContext(CompletionContext.Status.DISCARD, lbRequest, response)));throw NotFoundException.create(properties.isUse404(), Unable to find instance for url.getHost());}ServiceInstance retrievedInstance response.getServer();URI uri exchange.getRequest().getURI();// if the lb:scheme mechanism was used, use scheme as the default,// if the loadbalancer doesnt provide one.String overrideScheme retrievedInstance.isSecure() ? https : http;if (schemePrefix ! null) {overrideScheme url.getScheme();}DelegatingServiceInstance serviceInstance new DelegatingServiceInstance(retrievedInstance,overrideScheme);URI requestUrl reconstructURI(serviceInstance, uri);if (log.isTraceEnabled()) {log.trace(LoadBalancerClientFilter url chosen: requestUrl);}exchange.getAttributes().put(GATEWAY_REQUEST_URL_ATTR, requestUrl);exchange.getAttributes().put(GATEWAY_LOADBALANCER_RESPONSE_ATTR, response);supportedLifecycleProcessors.forEach(lifecycle - lifecycle.onStartRequest(lbRequest, response));}).then(chain.filter(exchange)).doOnError(throwable - supportedLifecycleProcessors.forEach(lifecycle - lifecycle.onComplete(new CompletionContextResponseData, ServiceInstance, RequestDataContext(CompletionContext.Status.FAILED, throwable, lbRequest,exchange.getAttribute(GATEWAY_LOADBALANCER_RESPONSE_ATTR))))).doOnSuccess(aVoid - supportedLifecycleProcessors.forEach(lifecycle - lifecycle.onComplete(new CompletionContextResponseData, ServiceInstance, RequestDataContext(CompletionContext.Status.SUCCESS, lbRequest,exchange.getAttribute(GATEWAY_LOADBALANCER_RESPONSE_ATTR),new ResponseData(exchange.getResponse(), new RequestData(exchange.getRequest()))))));}首先判断uri配置了lb需要根据服务名做负载转发
在这个filter前已经根据请求路径/ws和router配置将请求地址转换成了 服务名:请求路径的形式也就是将ws://localhost:8080/ws转化成了ws://im/ws
然后根据服务名im到nacos获取到服务的实际地址 ServiceInstance retrievedInstance response.getServer();其中包含了ip和端口
最后替换出实际要转发的地址
所以我们只要在这一步根据需要将端口8081改成8082就能实现我们要的效果了
最终解决方案
最初是想自定义一个HandlerMapping完成转发的但看下来后直接改源码更便捷一些所以直接在项目中新建一个同路径的类将源码copy进来覆盖掉这个Filter 然后在获取到nacos实例后修改掉端口号就能改变最终的目标地址
在获取服务实例ServiceInstance retrievedInstance response.getServer()这行后面加一段代码
if (url.toString().equals(ws://im/ws)) {try {Field field retrievedInstance.getClass().getDeclaredField(port);field.setAccessible(true);field.set(retrievedInstance, 8082);} catch (Exception e) {e.printStackTrace();}
}im相关的路由配置 - id: im_routeuri: lb://impredicates:- Path/im/**- id: im_ws_routeuri: lb:ws://impredicates:- Path/ws/**
