Resiliency4j CircuitBreaker试图在AOP中调用circuitBreaker逻辑，以实现在配置中禁用时不调用断路器。

Question

有条件地，我想通过设置spring.cloud.circuitbreaker.resilience4j.enabled=false来开关断路器。我的逻辑应该与断路器逻辑保持完整。

我尝试使用下面的演示示例扩展到我的需求，我试图绑定断路器调用的目标方法，基于断路器标志spring.cloud.circuitbreaker.resilience4j.enabled=true在application.property，true和false的情况下。可以有一个更简单的方法来实现这一点，帮助我，如果任何其他解决方案，除了我所尝试的。

示例： 弹簧云断路器.弹性4j示例

尝试调用愉快路径-在没有异常的情况下，可以在3秒内响应，因为在bean创建中时间限制器设置为3秒。

application.properties:

spring.cloud.circuitbreaker.resilience4j.enabled=true
spring.cloud.config.enabled=false
spring.cloud.config.import-check.enabled=false
spring.main.allow-bean-definition-overriding=true

控制器：

@GetMapping("/delay/{seconds}")
public Map delay(@PathVariable int seconds) {
   return mockService.delay(seconds);
}

MockService:

@ApplyCircuitBreaker
public Map delay(int seconds) {
    return rest.getForObject("https://httpbin.org/delay/" + seconds, Map.class);
}

Config类：

@Configuration
@ConditionalOnProperty(name = { "spring.cloud.circuitbreaker.resilience4j.enabled"}, matchIfMissing = true)
public class ResiliencyConfig {

    @Bean
    public Customizer<Resilience4JCircuitBreakerFactory> defaultCustomizer() {
        return factory -> factory.configureDefault(id -> new Resilience4JConfigBuilder(id)
            .timeLimiterConfig(TimeLimiterConfig.custom().timeoutDuration(Duration.ofSeconds(3)).build())
            .circuitBreakerConfig(CircuitBreakerConfig.ofDefaults())
            .build());
    }
}

ApplyCircuitBreaker -自定义注释仅适用于所需方法的断路器：

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface ApplyCircuitBreaker {
}

AOP: CircuitBreakerAroundAspect:

@Aspect
@Component
@ConditionalOnProperty(name = { "spring.cloud.circuitbreaker.resilience4j.enabled",
    "spring.cloud.circuitbreaker.resilience4j.reactive.enabled" }, matchIfMissing = true)
public class CircuitBreakerAroundAspect {

    @Autowired
    CircuitBreakerFactory circuitBreakerFactory;

    @Around("@annotation(com.ravibeli.circuitbreaker.aspects.ApplyCircuitBreaker)")
    public Object aroundAdvice(final ProceedingJoinPoint joinPoint) throws Throwable {
        log.info("Arguments passed to method are: {}", Arrays.toString(joinPoint.getArgs()));
        AtomicReference<Map<String, String>> fallback = new AtomicReference<>();
        Object proceed = circuitBreakerFactory.create(joinPoint.getSignature().toString())
            .run(() -> {
                try {
                    log.info("Inside CircuitBreaker logic in Aspect");
                    return joinPoint.proceed();
                } catch (Throwable t) {
                    log.error(t.getMessage());
                }
                return null;
            }, Throwable::getMessage);
        log.info("Result from method is: {}", proceed);
        return proceed;
    }
}

My requirement: circuitBreakerFactory.create(joinPoint.getSignature().toString()) .run(() -> ....)在这一行，当目标方法抛出异常时，控制应该转到回退机制调用。由于joinPoint.proceed()抛出异常，它将不得不处理异常--所以我在这里做错了，需要建议修复这个问题以解决需求。

错误日志：

{
    "timestamp": "2021-07-10T01:33:10.558+00:00",
    "status": 500,
    "error": "Internal Server Error",
/*
* 提示：该行代码过长，系统自动注释不进行高亮。一键复制会移除系统注释 
* "trace": "java.lang.ClassCastException: class java.lang.String cannot be cast to class java.util.Map (java.lang.String and java.util.Map are in module java.base of loader 'bootstrap')\r\n\tat com.ravibeli.circuitbreaker.service.MockService$$EnhancerBySpringCGLIB$$3e293bd0.delay(<generated>)\r\n\tat com.ravibeli.circuitbreaker.controllers.DemoController.delay(DemoController.java:53)\r\n\tat java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)\r\n\tat java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)\r\n\tat java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)\r\n\tat java.base/java.lang.reflect.Method.invoke(Method.java:566)\r\n\tat org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:197)\r\n\tat org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:141)\r\n\tat org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:106)\r\n\tat org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:894)\r\n\tat org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808)\r\n\tat org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)\r\n\tat org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1063)\r\n\tat org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963)\r\n\tat org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)\r\n\tat org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898)\r\n\tat javax.servlet.http.HttpServlet.service(HttpServlet.java:655)\r\n\tat org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)\r\n\tat javax.servlet.http.HttpServlet.service(HttpServlet.java:764)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:228)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163)\r\n\tat org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:190)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163)\r\n\tat org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)\r\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:190)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163)\r\n\tat org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)\r\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:190)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163)\r\n\tat org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)\r\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:190)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163)\r\n\tat org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)\r\n\tat org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)\r\n\tat org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542)\r\n\tat org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143)\r\n\tat org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)\r\n\tat org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)\r\n\tat org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357)\r\n\tat org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:382)\r\n\tat org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)\r\n\tat org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:893)\r\n\tat org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1723)\r\n\tat org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)\r\n\tat java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)\r\n\tat java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)\r\n\tat org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)\r\n\tat java.base/java.lang.Thread.run(Thread.java:834)\r\n",
*/
    "message": "class java.lang.String cannot be cast to class java.util.Map (java.lang.String and java.util.Map are in module java.base of loader 'bootstrap')",
    "path": "/delay/3"
}

Answer 1

1. 为了动态启用断路器，您可以使用Profiles或外部化配置(首选的方法是使用Profiles，您可以搜索更多关于它们的信息)
2. 就您方面的代码而言，它看起来和运行对我来说都很好。链接到代码。如果您能够共享到代码库的链接，以便进一步调查这个问题，那就更好了。然而，这似乎是一个小问题。

Answer 2

你好像在问几个不同的问题。

标题似乎是在问为什么当spring.cloud.circuitbreaker.resilience4j.enabled=false时方面仍然存在

问题是你有条件

@ConditionalOnProperty(name = { "spring.cloud.circuitbreaker.resilience4j.enabled",
    "spring.cloud.circuitbreaker.resilience4j.reactive.enabled" }, matchIfMissing = true)

它只是要求财产是存在的，而不是检查它设置为什么。您还需要设置havingValue=true。

尽管如此，我强烈建议不要为断路器做你自己的切分。使用Resiliancy4j提供的注释，并在那里指定回退方法。我希望这能解决你在退步时遇到的其他问题。

@Bulkhead(name = 'myService', fallbackMethod = "myFallback")
@CircuitBreaker(name = 'myService', fallbackMethod = "myFallback")
@RateLimiter(name = 'myService', fallbackMethod = "myFallback")
@TimeLimiter(name = 'myService', fallbackMethod = "myFallback")

Answer 3

谢谢，伙计们，你们的评论，有一个简单的想法来解决这个问题。我使用自定义工厂实现解决了这个问题，以使启用/禁用功能工作。

My GitHub示例代码： 弹簧云弹性4j