Resilience4j 从不调用回退方法

Question

我是 Resilience4j 和断路器模式的新手。

我为resilience4j 编写了一个示例。详情如下：

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>2.3.2.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>ir.co.isc</groupId>
<artifactId>circuit-breaker</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>circuit-breaker</name>
<description>Demo project for Spring Boot</description>

<properties>
    <java.version>11</java.version>
    <spring-cloud.version>Hoxton.SR6</spring-cloud.version>
</properties>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <!-- resilience4j dependency-->
    <dependency>
        <groupId>io.github.resilience4j</groupId>
        <artifactId>resilience4j-spring-boot2</artifactId>
        <version>1.5.0</version>
        <type>pom</type>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-aop</artifactId>
        <version>2.3.0.RELEASE</version>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-actuator</artifactId>
        <version>2.3.2.RELEASE</version>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
        <exclusions>
            <exclusion>
                <groupId>org.junit.vintage</groupId>
                <artifactId>junit-vintage-engine</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
</dependencies>

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-dependencies</artifactId>
            <version>${spring-cloud.version}</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
    </plugins>
</build>

application.yml:

resilience4j:
circuitbreaker:
    configs:
        default:
            registerHealthIndicator: true
            slidingWindowSize: 10
            minimumNumberOfCalls: 5
            permittedNumberOfCallsInHalfOpenState: 3
            automaticTransitionFromOpenToHalfOpenEnabled: true
            waitDurationInOpenState: 5s
            failureRateThreshold: 20
            eventConsumerBufferSize: 10
    instances:
        mainService:
            baseConfig: default

控制器类：

package ir.co.isc.circuitbreaker;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.ResponseStatus;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class MainServiceController {


@Autowired
private MainService mainService;


@GetMapping("/getSleuthTest")
@ResponseStatus(HttpStatus.OK)
public ResponseEntity<String> getSleuthTest(){
    String response = mainService.getResponse();
    return new ResponseEntity<>(response, HttpStatus.OK);
  }
 }

服务类：

package ir.co.isc.circuitbreaker;

import io.github.resilience4j.circuitbreaker.annotation.CircuitBreaker;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;

@Service
public class MainService {

private static final String MAIN_SERVICE = "mainService";

@Autowired
private RestTemplate restTemplate;

@Bean
public RestTemplate getRestTemplate() {
    return new RestTemplate();
}

@CircuitBreaker(name = MAIN_SERVICE, fallbackMethod="testFallBack")
public String getResponse(){
    return restTemplate.getForObject("http://localhost:8081/serviceOne", String.class);
}

private ResponseEntity<String> testFallBack(Exception e){
    return new ResponseEntity<>("In fallback method", HttpStatus.INTERNAL_SERVER_ERROR);
  }
}

SpringBootApplication 类：

package ir.co.isc.circuitbreaker;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class CircuitBreakerApplication {

public static void main(String[] args) {
    SpringApplication.run(CircuitBreakerApplication.class, args);
   }

}

我使用 postman runner 来调用我的 API。我将跑步者迭代次数设置为 200。 在 10 次成功的 API 调用后，我在此 url 中停止第三方： http://localhost:8081/serviceOne

据我了解，在停止第三方 API 并记录成功调用的最小次数后，resilience4j 开始计算故障率，当故障率大于 failureRateThreshold 时，调用回退方法（此处为服务类中的 testFallBack），电路状态从接近打开模式并返回 testFallBack() 方法中描述的我想要的答案。

但这永远不会发生（从未调用过 testFallBack() 方法）。我的申请有什么问题？

Answer 1

总的来说，经过这么多谷歌，我觉得只能从 Controller 调用 fallBack。我已经尝试了多次，但从服务中它不起作用。

由于您也是从服务调用它，这就是您面临此问题的原因，而不是如果您从控制器调用它，它应该适合您。