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我已经检查了网站上有关 Resilience4J 的问题，但他们的答案没有任何运气。我正在尝试@CircuitBreaker在我的 Spring Boot 2.x 项目中实现来自 Resilience4J 的注释。断路器是围绕一个非常简单的功能实现的。但是，当我提供错误的 URL 时，无论我发送多少次请求，电路都不会打开。我什至将所有内容提取到一个独立的应用程序中并运行 100 次，然后观察它只是无休止地失败。知道我做错了什么吗？

    @CircuitBreaker(name = "backendA")
    @Component
    public class ResilientClient {

        private HttpClient httpClient;

        private static final Logger log = LoggerFactory.getLogger(ResilientClient.class);

        public ResilientClient() {

            httpClient = HttpClient.newBuilder().build();
        }


        @Bulkhead(name = "backendA")
        public String processPostRequest(String body, String[] headers, String url) {

            HttpResponse<String> response = null;

            HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create(url))
                .POST(HttpRequest.BodyPublishers.ofString(body))
                .headers(headers)
                .build();

            try {
                response =  httpClient.send(request, HttpResponse.BodyHandlers.ofString());
            } catch (IOException e) {
                throw new HttpServerErrorException(HttpStatus.INTERNAL_SERVER_ERROR, "This is a remote exception");
            } catch (InterruptedException e) {
                e.printStackTrace();
                log.error("Interrupted Exception: " + e.getLocalizedMessage(), e);

            }
            return response != null ? response.body() : null;
    };

// None of these functions ever get invoked

    private String fallback(Throwable e){
        log.info("generic throwable caught");
        return "generic result";
    }

    private String fallback(String param1, String[] headers, String url, Throwable e) {
        log.info("Fallback method invoked for Throwable: " + param1);
        return null;
    }

    private String fallback(String param1, String[] headers, String url, ConnectException e) {
        log.info("Fallback method invoked for ConnectException: " + param1);
        return null;
    }

}

配置文件直接取自 Github 示例

resilience4j.circuitbreaker:
  configs:
    default:
      registerHealthIndicator: false
      slidingWindowSize: 10
      minimumNumberOfCalls: 5
      permittedNumberOfCallsInHalfOpenState: 3
      automaticTransitionFromOpenToHalfOpenEnabled: true
      waitDurationInOpenState: 2s
      failureRateThreshold: 50
      eventConsumerBufferSize: 10
      recordExceptions:
        - org.springframework.web.client.HttpServerErrorException
        - java.io.IOException
      ignoreExceptions:
        - io.github.robwin.exception.BusinessException
    shared:
      registerHealthIndicator: true
      slidingWindowSize: 100
      permittedNumberOfCallsInHalfOpenState: 30
      waitDurationInOpenState: 1s
      failureRateThreshold: 50
      eventConsumerBufferSize: 10
      ignoreExceptions:
        - io.github.robwin.exception.BusinessException
  instances:
    backendA:
      baseConfig: default
    backendB:
      registerHealthIndicator: true
      slidingWindowSize: 10
      minimumNumberOfCalls: 10
      permittedNumberOfCallsInHalfOpenState: 3
      waitDurationInOpenState: 1s
      failureRateThreshold: 50
      eventConsumerBufferSize: 10
      recordFailurePredicate: io.github.robwin.exception.RecordFailurePredicate
resilience4j.retry:
  configs:
    default:
      maxRetryAttempts: 2
      waitDuration: 100
      retryExceptions:
        - org.springframework.web.client.HttpServerErrorException
        - java.io.IOException
      ignoreExceptions:
        - io.github.robwin.exception.BusinessException
  instances:
    backendA:
      maxRetryAttempts: 3
    backendB:
      maxRetryAttempts: 3
resilience4j.bulkhead:
  configs:
    default:
      maxConcurrentCalls: 100
  instances:
    backendA:
      maxConcurrentCalls: 10
    backendB:
      maxWaitDuration: 10ms
      maxConcurrentCalls: 20

resilience4j.thread-pool-bulkhead:
  configs:
    default:
      maxThreadPoolSize: 4
      coreThreadPoolSize: 2
      queueCapacity: 2
  instances:
    backendA:
      baseConfig: default
    backendB:
      maxThreadPoolSize: 1
      coreThreadPoolSize: 1
      queueCapacity: 1

resilience4j.ratelimiter:
  configs:
    default:
      registerHealthIndicator: false
      limitForPeriod: 10
      limitRefreshPeriod: 1s
      timeoutDuration: 0
      eventConsumerBufferSize: 100
  instances:
    backendA:
      baseConfig: default
    backendB:
      limitForPeriod: 6
      limitRefreshPeriod: 500ms
      timeoutDuration: 3s

尝试测试它的代码

SpringBootApplication
public class CircuitsApplication {

    private static final Logger logger = LoggerFactory.getLogger(CircuitsApplication.class);

    static ResilientClient resilientClient = new ResilientClient();

    public static void main(String[] args) {
        //SpringApplication.run(CircuitsApplication.class, args);
        for (int i = 0; i < 100; i++){
            try {
                String body = "body content";
                String[] headers = new String[]{"header", "value"};
                String url = "http://a.bad.url";
                String result = resilientClient.processPostRequest(body, headers, url);
                logger.info(result);
            } catch (Exception ex){
                logger.info("Error caught in main loop");
                try {
                    Thread.sleep(500);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }

}

我尝试将 Circuitbreaker 注释添加到方法本身。我尝试过创建供应商并对其进行装饰。我试过添加隔板，移除隔板。我尝试添加具有不同签名的其他后备方法。我试过有和没有@Component。

我最终在日志中得到的只有 100 次：

14:33:10.348 [main] INFO c.t.circuits.CircuitsApplication - Error caught in main loop

我不确定我错过了什么。任何帮助将不胜感激。

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1 回答 1

3

我认为这行不通。首先，您正在实例化您的ResilientClientas new ResilientClient()。您必须使用创建的 Bean 而不是自己实例化它。@CircuitBreaker注释使用spring-aop 。所以你必须将你的类作为 SpringBootApplicaiton 运行。

其次，你只是记录HttpServerErrorException和IOException失败。因此断路器将所有其他异常（除了上面提到的异常及其子异常）视为成功。

于 2019-10-16T11:39:15.537 回答