电商网站建设相关书籍推荐,产品平面广告设计,wordpress 安装ftp,合肥网站搜索引擎优化自定义loadbalance实现feignclient的自定义路由
项目背景
服务A有多个同事同时开发#xff0c;每个同事都在dev或者test环境发布自己的代码#xff0c;注册到注册中心有好几个(本文nacos为例)#xff0c;这时候调用feign可能会导致请求到不同分支的服务上面#xff0c;会…自定义loadbalance实现feignclient的自定义路由
项目背景
服务A有多个同事同时开发每个同事都在dev或者test环境发布自己的代码注册到注册中心有好几个(本文nacos为例)这时候调用feign可能会导致请求到不同分支的服务上面会出现一些问题本文重点在于解决该问题
实操
解决方案
/*** author authorZhao* since 2023-08-03*/
EnableConfigurationProperties(LoadBalancerProperties.class)
public class LoadBalanceConfig{BeanConditionalOnMissingBeanpublic ReactorLoadBalancerServiceInstance reactorServiceInstanceLoadBalancer(Environment environment,LoadBalancerClientFactory loadBalancerClientFactory) {String name environment.getProperty(LoadBalancerClientFactory.PROPERTY_NAME);return new MyRoundRobinLoadBalancer(loadBalancerClientFactory.getLazyProvider(name, ServiceInstanceListSupplier.class), name);}
}//Configuration(proxyBeanMethods false)
//LoadBalancerClients(defaultConfiguration LoadBalanceConfig.class) 全局配置
//LoadBalancerClient(value user-center-service,configuration LoadBalanceConfig.class) //单个配置
public class LoadBalance {}/*** A Round-Robin-based implementation of {link ReactorServiceInstanceLoadBalancer}.** author Spencer Gibb* author Olga Maciaszek-Sharma* author Zhuozhi JI*/
public class MyRoundRobinLoadBalancer implements ReactorServiceInstanceLoadBalancer {private static final Log log LogFactory.getLog(CubeRoundRobinLoadBalancer.class);final AtomicInteger position;final String serviceId;ObjectProviderServiceInstanceListSupplier serviceInstanceListSupplierProvider;/*** param serviceInstanceListSupplierProvider a provider of* {link ServiceInstanceListSupplier} that will be used to get available instances* param serviceId id of the service for which to choose an instance*/public CubeRoundRobinLoadBalancer(ObjectProviderServiceInstanceListSupplier serviceInstanceListSupplierProvider,String serviceId) {this(serviceInstanceListSupplierProvider, serviceId, new Random().nextInt(1000));}/*** param serviceInstanceListSupplierProvider a provider of* {link ServiceInstanceListSupplier} that will be used to get available instances* param serviceId id of the service for which to choose an instance* param seedPosition Round Robin element position marker*/public CubeRoundRobinLoadBalancer(ObjectProviderServiceInstanceListSupplier serviceInstanceListSupplierProvider,String serviceId, int seedPosition) {this.serviceId serviceId;this.serviceInstanceListSupplierProvider serviceInstanceListSupplierProvider;this.position new AtomicInteger(seedPosition);}SuppressWarnings(rawtypes)Override// see original// https://github.com/Netflix/ocelli/blob/master/ocelli-core/// src/main/java/netflix/ocelli/loadbalancer/RoundRobinLoadBalancer.javapublic MonoResponseServiceInstance choose(Request request) {ServiceInstanceListSupplier supplier serviceInstanceListSupplierProvider.getIfAvailable(NoopServiceInstanceListSupplier::new);return supplier.get(request).next().map(serviceInstances - processInstanceResponse(supplier, serviceInstances));}private ResponseServiceInstance processInstanceResponse(ServiceInstanceListSupplier supplier,ListServiceInstance serviceInstances) {ResponseServiceInstance serviceInstanceResponse getInstanceResponse(serviceInstances);if (supplier instanceof SelectedInstanceCallback serviceInstanceResponse.hasServer()) {((SelectedInstanceCallback) supplier).selectedServiceInstance(serviceInstanceResponse.getServer());}return serviceInstanceResponse;}private ResponseServiceInstance getInstanceResponse(ListServiceInstance instances) {for (ServiceInstance instance : instances) {if(instance instanceof NacosServiceInstance nacosServiceInstance){//项目注册的时候在配置一个元数据后面可以根据当前上下文拿到当前tag进行匹配默认使用base分支String s instance.getMetadata().get(feature-tag);if(base.equals(s)){return new DefaultResponse(nacosServiceInstance);}}}if (instances.isEmpty()) {if (log.isWarnEnabled()) {log.warn(No servers available for service: serviceId);}return new EmptyResponse();}// Ignore the sign bit, this allows pos to loop sequentially from 0 to// Integer.MAX_VALUEint pos this.position.incrementAndGet() Integer.MAX_VALUE;ServiceInstance instance instances.get(pos % instances.size());return new DefaultResponse(instance);}}loadbalance执行过程
调用流程
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feign.SynchronousMethodHandler#executeAndDecode
-feign.Client#execute
-FeignBlockingLoadBalancerClient#execute
public Response execute(Request request, Request.Options options) throws IOException {final URI originalUri URI.create(request.url());String serviceId originalUri.getHost();Assert.state(serviceId ! null, Request URI does not contain a valid hostname: originalUri);String hint getHint(serviceId);DefaultRequestRequestDataContext lbRequest new DefaultRequest(new RequestDataContext(buildRequestData(request), hint));SetLoadBalancerLifecycle supportedLifecycleProcessors LoadBalancerLifecycleValidator.getSupportedLifecycleProcessors(//loadBalancerClientFactory是NamedContextFactory的子类 容器map刷新user-center-service子容器loadBalancerClientFactory.getInstances(serviceId, LoadBalancerLifecycle.class),RequestDataContext.class, ResponseData.class, ServiceInstance.class);supportedLifecycleProcessors.forEach(lifecycle - lifecycle.onStart(lbRequest));//根据serviceId拿到ReactiveLoadBalancer执行choose方法然后到了我们的方法ServiceInstance instance loadBalancerClient.choose(serviceId, lbRequest);org.springframework.cloud.client.loadbalancer.ResponseServiceInstance lbResponse new DefaultResponse(instance);if (instance null) {String message Load balancer does not contain an instance for the service serviceId;if (LOG.isWarnEnabled()) {LOG.warn(message);}supportedLifecycleProcessors.forEach(lifecycle - lifecycle.onComplete(new CompletionContextResponseData, ServiceInstance, RequestDataContext(CompletionContext.Status.DISCARD, lbRequest, lbResponse)));return Response.builder().request(request).status(HttpStatus.SERVICE_UNAVAILABLE.value()).body(message, StandardCharsets.UTF_8).build();}String reconstructedUrl loadBalancerClient.reconstructURI(instance, originalUri).toString();Request newRequest buildRequest(request, reconstructedUrl);LoadBalancerProperties loadBalancerProperties loadBalancerClientFactory.getProperties(serviceId);return executeWithLoadBalancerLifecycleProcessing(delegate, options, newRequest, lbRequest, lbResponse,supportedLifecycleProcessors, loadBalancerProperties.isUseRawStatusCodeInResponseData());}后面MyRoundRobinLoadBalancer其实是抄袭RoundRobinLoadBalancer的实现默认就是轮训
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