spring webclient负载均衡

Question

以前从未使用过带负载平衡的Web客户端，我放松了https://spring.io/guides/gs/spring-cloud-loadbalancer/并实现了Web客户端负载均衡器，现在我尝试使用helthchecks并遇到问题。

    @Bean
    @Primary
    ServiceInstanceListSupplier serviceInstanceListSupplier(ConfigurableApplicationContext ctx) {
        return ServiceInstanceListSupplier
                .builder()
                .withRetryAwareness()
                .withHealthChecks()
                .withBase(new RestCaller("restCaller"))
                .build(ctx);
    }

我收到以下错误

2021-06-27 17:32:01.562  WARN 12252 --- [     parallel-4] o.s.c.l.core.RoundRobinLoadBalancer      : No servers available for service: httpbin.org
2021-06-27 17:32:01.564  WARN 12252 --- [     parallel-4] eactorLoadBalancerExchangeFilterFunction : LoadBalancer does not contain an instance for the service httpbin.org
2021-06-27 17:32:01.606  WARN 12252 --- [     parallel-4] o.s.c.l.core.RoundRobinLoadBalancer      : No servers available for service: httpbin.org
2021-06-27 17:32:01.606  WARN 12252 --- [     parallel-4] eactorLoadBalancerExchangeFilterFunction : LoadBalancer does not contain an instance for the service httpbin.org
2021-06-27 17:32:01.607  WARN 12252 --- [     parallel-4] o.s.c.l.core.RoundRobinLoadBalancer      : No servers available for service: httpbin.org
2021-06-27 17:32:01.607  WARN 12252 --- [     parallel-4] eactorLoadBalancerExchangeFilterFunction : LoadBalancer does not contain an instance for the service httpbin.org
2021-06-27 17:32:01.607  WARN 12252 --- [     parallel-4] o.s.c.l.core.RoundRobinLoadBalancer      : No servers available for service: restCaller
2021-06-27 17:32:01.608  WARN 12252 --- [     parallel-4] eactorLoadBalancerExchangeFilterFunction : LoadBalancer does not contain an instance for the service restCaller

当我评论“withHealthChecks()”时，一切都按预期进行。我的主要目标是 禁用“DefaultServiceInstance”，以防它失败（意味着 http 状态 503 或 404 或任何错误）。

我在 https://github.com/ozkanpakdil/spring-examples/tree/master/web-client-loadbalancer 准备了一个重现器只需运行“mvn test”你就会看到错误。您可以在https://github.com/ozkanpakdil/spring-examples/tree/master/web-client-loadbalancer查看配置。

Answer 1

感谢您提供样品。已经经历过了。有2个问题：

1. 同一个

   @LoadBalanced WebClient.Builder

   实例既用于处理原始请求，又用于发送运行状况检查请求，因此从

   HealthCheckServiceInstanceListSupplier

   发出的调用是使用负载平衡的

   Webclient

   而不是非负载平衡的来完成的一。由于在此阶段使用的是真实主机，因此应使用非负载平衡的

   Webclient

   实例。您可以通过在配置中实例化 2 个单独的

   Webclient.Builder

   bean 并使用限定符将非负载平衡的 bean 传递给

   HealthCheckServiceInstanceListSupplier

   来实现这一目标，如下所示：

    @Configuration
    @LoadBalancerClient(name = "restCaller", configuration = RestCallerConfiguration.class)
    public class WebClientConfig {
   
    @LoadBalanced
    @Bean
    @Qualifier("loadBalancedWebClientBuilder")
    WebClient.Builder loadBalancedWebClientBuilder() {
        return WebClient.builder();
    }
   
    @Bean
    @Qualifier("webClientBuilder")
    WebClient.Builder webClientBuilder() {
        return WebClient.builder();
    }
   }
   
    @Configuration
    public class RestCallerConfiguration {
   
    @Autowired
    @Qualifier("webClientBuilder")
    WebClient.Builder webClientBuilder;
   
    @Bean
    @Primary
    ServiceInstanceListSupplier     serviceInstanceListSupplier(ConfigurableApplicationContext ctx) {
        return ServiceInstanceListSupplier
                .builder()
                .withRetryAwareness()
                .withHealthChecks(webClientBuilder.build())
                .withBase(new RestCaller("restCaller"))
                .build(ctx);
    }
   

2. HealthCheckServiceInstanceListSupplier

   在运行状况检查 URL 发送请求以验证服务实例是否处于活动状态。默认情况下，我们假设协作服务的依赖项中有

   spring-boot-starter-actuator

   ，并且请求在

   /actuator/health

   端点发送。由于测试使用的

   httpbin

   中未配置此端点，因此我们得到

   404

   。更改属性中的运行状况检查路径将解决该问题：

    spring.cloud.loadbalancer.health-check.path.default=/
   

我已经在这里推送了一个具有固定配置的分支。如果您使用此设置运行测试，它就会通过。