Resilience4j断路器不工作

Question

我在使用Spring Cloud Resilience4j实现断路器时遇到了一个问题。

在一些教程之后，我尝试在项目中添加必要的依赖项。此外，我尝试添加配置，但仍然无法打开电路，也无法调用回退方法。

请从不同的文件中找到代码片段。

我是个断路器模式的新手。任何帮助都将受到高度的感谢。

pom.xml

    <?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
<parent>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-parent</artifactId>
   <version>2.5.5</version>
   <relativePath/> <!-- lookup parent from repository -->
</parent>
    <properties>
    <java.version>11</java.version>
    <spring-cloud.version>2020.0.4</spring-cloud.version>
    </properties>
    <dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-actuator</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-circuitbreaker-resilience4j</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-aop</artifactId>
    </dependency>
<dependencies>
</project>

应用程序属性

resilience4j.circuitbreaker.instances.test-api.register-health-indicator=true
resilience4j.circuitbreaker.instances.test-api.minimum-number-of-calls=4
resilience4j.circuitbreaker.instances.test-api.failure-rate-threshold=50
resilience4j.circuitbreaker.instances.test-api.permitted-number-of-calls-in-half-open-state=3
resilience4j.circuitbreaker.instances.test-api.wait-duration-in-open-state=30s
resilience4j.circuitbreaker.instances.test-api.automatic-transition-from-open-to-half-open-enabled=true
resilience4j.circuitbreaker.instances.test-api.record-exceptions=com.testapi.exception.ServiceUnavailableError

服务类代码片段

@CircuitBreaker(name = "test-api", fallbackMethod = "storeResponseFallback")
    public TestResponse storeResponse(String apiURL, HttpEntity<String> entityrequest) {

        TestResponse testResponse = new TestResponse();
        Optional<ResponseEntity<TestResponse>> response = Optional.empty();
        Future<ResponseEntity<TestResponse>> responseFuture;

        ExecutorService executor = Executors.newFixedThreadPool(10);

        log.debug("Calling Extrenal API, Request Body: {}", entityrequest.toString());

        try {
            //Service call returns a future
            responseFuture = executor.submit(() -> restTemplate.postForEntity(apiURL, entityrequest, TestResponse.class));
            response = Optional.ofNullable(responseFuture.get());
            log.info("Got response from external API");


            if ((response.isPresent()) && (response.get().hasBody())) {
                testResponse = response.get().getBody();
            }

        } catch (Exception exception) {
            log.error("External api call got failed with an error");
            Thread.currentThread().interrupt();            
            throw new ServiceUnavailableError();
        }


        return testResponse;

    }
    
    
    public TestResponse storeResponseFallback(ServiceUnavailableError ex) {
        log.error("Executing Fallback Method For General exceptions");
        throw new ServiceUnavailableError();
    }

ServiceUnavailableError Java文件

@Data
@AllArgsConstructor
@NoArgsConstructor
public class ServiceUnavailableError extends RuntimeException{
    private static final long serialVersionUID = 2382122402994502766L;

    private String message;

}

Answer 1

回退方法的签名错误。它应该包含实际方法的所有参数(在您的示例中，storeResponseFallback是回退方法，storeResponse是实际方法)，以及异常。请确保删除try catch块。您不希望自己处理异常，而应该让断路器为您处理它。请看下面的代码，它来自给定的链接https://resilience4j.readme.io/docs/getting-started-3

@CircuitBreaker(name = BACKEND, fallbackMethod = "fallback")
public Mono<String> method(String param1) {
    return Mono.error(new NumberFormatException());
}

private Mono<String> fallback(String param1, IllegalArgumentException e) {
    return Mono.just("test");
}

尝试使用以下yaml文件我在现有代码中使用了以下配置，我使用了yaml而不是属性文件。这似乎保持在打开状态，并且只调用回退方法。

resilience4j.circuitbreaker:
  configs:
    default:
      slidingWindowSize: 4
      permittedNumberOfCallsInHalfOpenState: 10
      waitDurationInOpenState: 10000
      failureRateThreshold: 60
      eventConsumerBufferSize: 10
      registerHealthIndicator: true
    someShared:
      slidingWindowSize: 3
      permittedNumberOfCallsInHalfOpenState: 10
  instances:
    test-api:
      baseConfig: default
      waitDurationInOpenState: 500000
    backendB:
      baseConfig: someShared

下面是更新后的回退方法

public TestResponse storeResponseFallback(String apiURL, String entityrequest, java.lang.Throwable t) {
        log.error("Executing Fallback Method For General exceptions "+t.getMessage());
        return new TestResponse("Frm Fallback");// Making sure to send a blank response
    }