【发布时间】：2021-09-20 05:58:57
【问题描述】：
有条件地我想通过设置spring.cloud.circuitbreaker.resilience4j.enabled=false 来关闭/打开断路器开关。我的逻辑应该不受断路器逻辑的影响。
我尝试使用下面的演示示例来扩展我的要求，我正在尝试根据application.property、true 和false 案例中的断路器标志spring.cloud.circuitbreaker.resilience4j.enabled=true 绑定目标方法上的断路器调用。可能有一种更简单的方法来实现这一点，如果有任何其他解决方案，请帮助我。
示例： spring cloud circuit-breaker-resiliency4j example
尝试调用快乐路径 - 没有异常时工作正常[响应在 3 秒内出现，因为时间限制器在 bean 创建中设置为 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);
}
模拟服务：
@ApplyCircuitBreaker
public Map delay(int seconds) {
return rest.getForObject("https://httpbin.org/delay/" + seconds, Map.class);
}
配置类：
@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：
@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;
}
}
我的要求：
circuitBreakerFactory.create(joinPoint.getSignature().toString()) .run(() -> ....)在这一行，当目标方法抛出异常时，controll应该去fallback机制调用。由于 joinPoint.proceed() 抛出异常，它强制处理异常 - 所以我在这里做错了，需要建议来解决这个问题。
错误日志：
{
"timestamp": "2021-07-10T01:33:10.558+00:00",
"status": 500,
"error": "Internal Server Error",
"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"
}
【问题讨论】：
-
什么是回退方法，为什么在 catch 块中没有尝试回退？
-
控制不会去 fallBack 部分本身，因为 return 语句被强制放置，然后 fallback 部分变得无法访问，由于 joinPoint.proceed() 强制处理异常，它有一个限制。跨度>
标签： aop circuit-breaker resilience4j-retry spring-cloud-circuitbreaker