SpringCloud升级之路2020.0.x版-34.验证重试配置正确性(1)

SpringCloud升级之路2020.0.x版-34.验证重试配置正确性(1)
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本系列代码地址: https://github.com/JoJoTec/sp...
在前面一节,我们利用 resilience4j 粘合了 OpenFeign 实现了断路器、重试以及线程隔离,并使用了新的负载均衡算法优化了业务激增时的负载均衡算法表现。这一节,我们开始编写单元测试验证这些功能的正确性,以便于日后升级依赖,修改的时候能保证正确性。同时,通过单元测试,我们更能深入理解 Spring Cloud。
验证重试配置 对于我们实现的重试,我们需要验证:
  1. 验证配置正确加载:即我们在 Spring 配置(例如 application.yml)中的加入的 Resilience4j 的配置被正确加载应用了。
  2. 验证针对 ConnectTimeout 重试正确:FeignClient 可以配置 ConnectTimeout 连接超时时间,如果连接超时会有连接超时异常抛出,对于这种异常无论什么请求都应该重试,因为请求并没有发出。
  3. 验证针对断路器异常的重试正确:断路器是微服务实例方法级别的,如果抛出断路器打开异常,应该直接重试下一个实例。
  4. 验证针对限流器异常的重试正确:当某个实例线程隔离满了的时候,抛出线程限流异常应该直接重试下一个实例。
  5. 验证针对非 2xx 响应码可重试的方法重试正确
  6. 验证针对非 2xx 响应码不可重试的方法没有重试
  7. 验证针对可重试的方法响应超时异常重试正确:FeignClient 可以配置 ReadTimeout 即响应超时,如果方法可以重试,则需要重试。
  8. 验证针对不可重试的方法响应超时异常不能重试:FeignClient 可以配置 ReadTimeout 即响应超时,如果方法不可以重试,则不能重试。
验证配置正确加载
我们可以定义不同的 FeignClient,之后检查 resilience4j 加载的重试配置来验证重试配置的正确加载。
【SpringCloud升级之路2020.0.x版-34.验证重试配置正确性(1)】首先定义两个 FeignClient,微服务分别是 testService1 和 testService2,contextId 分别是 testService1Client 和 testService2Client
@FeignClient(name = "testService1", contextId = "testService1Client") public interface TestService1Client { @GetMapping("/anything") HttpBinAnythingResponse anything(); } @FeignClient(name = "testService2", contextId = "testService2Client") public interface TestService2Client { @GetMapping("/anything") HttpBinAnythingResponse anything(); }

然后,我们增加 Spring 配置,使用 SpringExtension 编写单元测试类:
//SpringExtension也包含了 Mockito 相关的 Extension,所以 @Mock 等注解也生效了 @ExtendWith(SpringExtension.class) @SpringBootTest(properties = { //默认请求重试次数为 3 "resilience4j.retry.configs.default.maxAttempts=3", // testService2Client 里面的所有方法请求重试次数为 2 "resilience4j.retry.configs.testService2Client.maxAttempts=2", }) @Log4j2 public class OpenFeignClientTest { @SpringBootApplication @Configuration public static class App { } }

编写测试代码,验证配置加载正确性:
@Test public void testConfigureRetry() { //读取所有的 Retry List retries = retryRegistry.getAllRetries().asJava(); //验证其中的配置是否符合我们填写的配置 Map retryMap = retries.stream().collect(Collectors.toMap(Retry::getName, v -> v)); //我们初始化 Retry 的时候,使用 FeignClient 的 ContextId 作为了 Retry 的 Name Retry retry = retryMap.get("testService1Client"); //验证 Retry 配置存在 Assertions.assertNotNull(retry); //验证 Retry 配置符合我们的配置 Assertions.assertEquals(retry.getRetryConfig().getMaxAttempts(), 3); retry = retryMap.get("testService2Client"); //验证 Retry 配置存在 Assertions.assertNotNull(retry); //验证 Retry 配置符合我们的配置 Assertions.assertEquals(retry.getRetryConfig().getMaxAttempts(), 2); }

验证针对 ConnectTimeout 重试正确
我们可以通过针对一个微服务注册两个实例,一个实例是连接不上的,另一个实例是可以正常连接的,无论怎么调用 FeignClient,请求都不会失败,来验证重试是否生效。我们使用 HTTP 测试网站来测试,即 http://httpbin.org 。这个网站的 api 可以用来模拟各种调用。其中 /status/{status} 就是将发送的请求原封不动的在响应中返回。在单元测试中,我们不会单独部署一个注册中心,而是直接 Mock spring cloud 中服务发现的核心接口 DiscoveryClient,并且将我们 Eureka 的服务发现以及注册通过配置都关闭,即:
//SpringExtension也包含了 Mockito 相关的 Extension,所以 @Mock 等注解也生效了 @ExtendWith(SpringExtension.class) @SpringBootTest(properties = { //关闭 eureka client "eureka.client.enabled=false", //默认请求重试次数为 3 "resilience4j.retry.configs.default.maxAttempts=3" }) @Log4j2 public class OpenFeignClientTest { @SpringBootApplication @Configuration public static class App { @Bean public DiscoveryClient discoveryClient() { //模拟两个服务实例 ServiceInstance service1Instance1 = Mockito.spy(ServiceInstance.class); ServiceInstance service1Instance4 = Mockito.spy(ServiceInstance.class); Map zone1 = Map.ofEntries( Map.entry("zone", "zone1") ); when(service1Instance1.getMetadata()).thenReturn(zone1); when(service1Instance1.getInstanceId()).thenReturn("service1Instance1"); when(service1Instance1.getHost()).thenReturn("httpbin.org"); when(service1Instance1.getPort()).thenReturn(80); when(service1Instance4.getInstanceId()).thenReturn("service1Instance4"); when(service1Instance4.getHost()).thenReturn("www.httpbin.org"); //这个port连不上,测试 IOException when(service1Instance4.getPort()).thenReturn(18080); DiscoveryClient spy = Mockito.spy(DiscoveryClient.class); //微服务 testService3 有两个实例即 service1Instance1 和 service1Instance4 Mockito.when(spy.getInstances("testService3")) .thenReturn(List.of(service1Instance1, service1Instance4)); return spy; } } }

编写 FeignClient:
@FeignClient(name = "testService3", contextId = "testService3Client") public interface TestService3Client { @PostMapping("/anything") HttpBinAnythingResponse anything(); }

调用 TestService3Client 的 anything 方法,验证是否有重试:
@SpyBean private TestService3Client testService3Client; /** * 验证对于有不正常实例(正在关闭的实例,会 connect timeout)请求是否正常重试 */ @Test public void testIOExceptionRetry() { //防止断路器影响 circuitBreakerRegistry.getAllCircuitBreakers().asJava().forEach(CircuitBreaker::reset); for (int i = 0; i < 5; i++) { Span span = tracer.nextSpan(); try (Tracer.SpanInScope cleared = tracer.withSpanInScope(span)) { //不抛出异常,则正常重试了 testService3Client.anything(); testService3Client.anything(); } } }

这里强调一点,由于我们在这个类中还会测试其他异常,以及断路器,我们需要避免这些测试一起执行的时候,断路器打开了,所以我们在所有测试调用 FeignClient 的方法开头,清空所有断路器的数据,通过:
circuitBreakerRegistry.getAllCircuitBreakers().asJava().forEach(CircuitBreaker::reset);

并且通过日志中可以看出由于 connect timeout 进行重试:
call url: POST -> http://www.httpbin.org:18080/anything, ThreadPoolStats(testService3Client:www.httpbin.org:18080): {"coreThreadPoolSize":10,"maximumThreadPoolSize":10,"queueCapacity":100,"queueDepth":0,"remainingQueueCapacity":100,"threadPoolSize":1}, CircuitBreakStats(testService3Client:www.httpbin.org:18080:public abstract com.github.jojotech.spring.cloud.webmvc.test.feign.HttpBinAnythingResponse com.github.jojotech.spring.cloud.webmvc.test.feign.OpenFeignClientTest$TestService3Client.anything()): {"failureRate":-1.0,"numberOfBufferedCalls":0,"numberOfFailedCalls":0,"numberOfNotPermittedCalls":0,"numberOfSlowCalls":0,"numberOfSlowFailedCalls":0,"numberOfSlowSuccessfulCalls":0,"numberOfSuccessfulCalls":0,"slowCallRate":-1.0} TestService3Client#anything() response: 582-Connect to www.httpbin.org:18080 [www.httpbin.org/34.192.79.103, www.httpbin.org/18.232.227.86, www.httpbin.org/3.216.167.140, www.httpbin.org/54.156.165.4] failed: Connect timed out, should retry: true call url: POST -> http://httpbin.org:80/anything, ThreadPoolStats(testService3Client:httpbin.org:80): {"coreThreadPoolSize":10,"maximumThreadPoolSize":10,"queueCapacity":100,"queueDepth":0,"remainingQueueCapacity":100,"threadPoolSize":1}, CircuitBreakStats(testService3Client:httpbin.org:80:public abstract com.github.jojotech.spring.cloud.webmvc.test.feign.HttpBinAnythingResponse com.github.jojotech.spring.cloud.webmvc.test.feign.OpenFeignClientTest$TestService3Client.anything()): {"failureRate":-1.0,"numberOfBufferedCalls":0,"numberOfFailedCalls":0,"numberOfNotPermittedCalls":0,"numberOfSlowCalls":0,"numberOfSlowFailedCalls":0,"numberOfSlowSuccessfulCalls":0,"numberOfSuccessfulCalls":0,"slowCallRate":-1.0} response: 200 - OK

验证针对断路器异常的重试正确
通过系列前面的源码分析,我们知道 spring-cloud-openfeign 的 FeignClient 其实是懒加载的。所以我们实现的断路器也是懒加载的,需要先调用,之后才会初始化断路器。所以这里如果我们要模拟断路器打开的异常,需要先手动读取载入断路器,之后才能获取对应方法的断路器,修改状态。
我们先定义一个 FeignClient:
@FeignClient(name = "testService1", contextId = "testService1Client") public interface TestService1Client { @GetMapping("/anything") HttpBinAnythingResponse anything(); }

使用前面同样的方式,给这个微服务添加实例:
//SpringExtension也包含了 Mockito 相关的 Extension,所以 @Mock 等注解也生效了 @ExtendWith(SpringExtension.class) @SpringBootTest(properties = { //关闭 eureka client "eureka.client.enabled=false", //默认请求重试次数为 3 "resilience4j.retry.configs.default.maxAttempts=3", //增加断路器配置 "resilience4j.circuitbreaker.configs.default.failureRateThreshold=50", "resilience4j.circuitbreaker.configs.default.slidingWindowType=COUNT_BASED", "resilience4j.circuitbreaker.configs.default.slidingWindowSize=5", "resilience4j.circuitbreaker.configs.default.minimumNumberOfCalls=2", }) @Log4j2 public class OpenFeignClientTest { @SpringBootApplication @Configuration public static class App { @Bean public DiscoveryClient discoveryClient() { //模拟两个服务实例 ServiceInstance service1Instance1 = Mockito.spy(ServiceInstance.class); ServiceInstance service1Instance3 = Mockito.spy(ServiceInstance.class); Map zone1 = Map.ofEntries( Map.entry("zone", "zone1") ); when(service1Instance1.getMetadata()).thenReturn(zone1); when(service1Instance1.getInstanceId()).thenReturn("service1Instance1"); when(service1Instance1.getHost()).thenReturn("httpbin.org"); when(service1Instance1.getPort()).thenReturn(80); when(service1Instance3.getMetadata()).thenReturn(zone1); when(service1Instance3.getInstanceId()).thenReturn("service1Instance3"); //这其实就是 httpbin.org ,为了和第一个实例进行区分加上 www when(service1Instance3.getHost()).thenReturn("www.httpbin.org"); DiscoveryClient spy = Mockito.spy(DiscoveryClient.class); //微服务 testService3 有两个实例即 service1Instance1 和 service1Instance4 Mockito.when(spy.getInstances("testService1")) .thenReturn(List.of(service1Instance1, service1Instance3)); return spy; } } }

然后,编写测试代码:
@Test public void testRetryOnCircuitBreakerException() { //防止断路器影响 circuitBreakerRegistry.getAllCircuitBreakers().asJava().forEach(CircuitBreaker::reset); CircuitBreaker testService1ClientInstance1Anything; try { testService1ClientInstance1Anything = circuitBreakerRegistry .circuitBreaker("testService1Client:httpbin.org:80:public abstract com.github.jojotech.spring.cloud.webmvc.test.feign.HttpBinAnythingResponse com.github.jojotech.spring.cloud.webmvc.test.feign.OpenFeignClientTest$TestService1Client.anything()", "testService1Client"); } catch (ConfigurationNotFoundException e) { //找不到就用默认配置 testService1ClientInstance1Anything = circuitBreakerRegistry .circuitBreaker("testService1Client:httpbin.org:80:public abstract com.github.jojotech.spring.cloud.webmvc.test.feign.HttpBinAnythingResponse com.github.jojotech.spring.cloud.webmvc.test.feign.OpenFeignClientTest$TestService1Client.anything()"); } //将断路器打开 testService1ClientInstance1Anything.transitionToOpenState(); //调用多次,调用成功即对断路器异常重试了 for (int i = 0; i < 10; i++) { this.testService1Client.anything(); } }

运行测试,日志中可以看出,针对断路器打开的异常进行重试了:
2021-11-13 03:40:13.546INFO [,,] 4388 --- [main] c.g.j.s.c.w.f.DefaultErrorDecoder: TestService1Client#anything() response: 581-CircuitBreaker 'testService1Client:httpbin.org:80:public abstract com.github.jojotech.spring.cloud.webmvc.test.feign.HttpBinAnythingResponse com.github.jojotech.spring.cloud.webmvc.test.feign.OpenFeignClientTest$TestService1Client.anything()' is OPEN and does not permit further calls, should retry: true

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SpringCloud升级之路2020.0.x版-34.验证重试配置正确性(1)
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