Feign跨服务调用报无/error显式映射、404/500异常排查咨询

问题表现 #

• 基于Feign实现微服务间调用时，接口返回500内部服务器错误，日志提示不存在/error路径的显式映射
• 核心异常为Feign调用GET请求http://stock-Api/get/MRF（绑定Cal#invokegetprice(String)方法）时抛出feign.FeignException$NotFound: 404异常
• 被调用服务返回No message available提示，找不到的请求路径为/get/MRF，触发本次报错的上游请求路径为/gettotal/MRF/2
• 完整错误响应及堆栈如下：

{
  "timestamp": "2022-07-03T09:38:12.692+00:00",
  "status": 500,
  "error": "Internal Server Error",
  "trace": "feign.FeignException$NotFound: [404] during [GET] to [http://stock-Api/get/MRF] [Cal#invokegetprice(String)]: [{\"timestamp\":\"2022-07-03T09:38:12.685+00:00\",\"status\":404,\"error\":\"Not Found\",\"message\":\"No message available\",\"path\":\"/get/MRF\"}]\n\tat feign.FeignException.clientErrorStatus(FeignException.java:219)\n\tat feign.FeignException.errorStatus(FeignException.java:194)\n\tat feign.FeignException.errorStatus(FeignException.java:185)\n\tat feign.codec.ErrorDecoder$Default.decode(ErrorDecoder.java:92)\n\tat feign.AsyncResponseHandler.handleResponse(AsyncResponseHandler.java:96)\n\tat feign.SynchronousMethodHandler.executeAndDecode(SynchronousMethodHandler.java:138)\n\tat feign.SynchronousMethodHandler.invoke(SynchronousMethodHandler.java:89)\n\tat feign.ReflectiveFeign$FeignInvocationHandler.invoke(ReflectiveFeign.java:100)\n\tat jdk.proxy4/jdk.proxy4.$Proxy108.invokegetprice(Unknown Source)\n\tat com.stock.demo.Controller.CalController.cal(CalController.java:22)\n\tat java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)\n\tat java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)\n\tat java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)\n\tat java.base/java.lang.reflect.Method.invoke(Method.java:568)\n\tat org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205)\n\tat org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:150)\n\tat org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117)\n\tat org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895)\n\tat org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808)\n\tat org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)\n\tat org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1067)\n\tat org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963)\n\tat org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)\n\tat org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898)\n\tat javax.servlet.http.HttpServlet.service(HttpServlet.java:655)\n\tat org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)\n\tat javax.servlet.http.HttpServlet.service(HttpServlet.java:764)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)\n\tat org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)\n\tat org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)\n\tat org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)\n\tat org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)\n\tat org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197)\n\tat org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)\n\tat org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541)\n\tat org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135)\n\tat org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)\n\tat org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)\n\tat org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:360)\n\tat org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:399)\n\tat org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)\n\tat org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:890)\n\tat org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1787)\n\tat org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)\n\tat org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)\n\tat org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)\n\tat org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)\n\tat java.base/java.lang.Thread.run(Thread.java:833)\n",
  "message": "[404] during [GET] to [http://stock-Api/get/MRF] [Cal#invokegetprice(String)]: [{\"timestamp\":\"2022-07-03T09:38:12.685+00:00\",\"status\":404,\"error\":\"Not Found\",\"message\":\"No message available\",\"path\":\"/get/MRF\"}]",
  "path": "/gettotal/MRF/2"
}

根因说明 #

日志中提示的/error路径无映射是SpringBoot默认错误处理机制的次生提示，核心问题是Feign发起的请求没有匹配到被调用服务的任何接口，被调用方返回了404状态码。

修复步骤 #

• 核对被调用服务接口定义：直连stock服务实例地址，验证/get/MRF接口是否存在、请求方法是否为GET，同步检查服务是否配置server.servlet.context-path上下文路径，若有配置Feign请求必须携带对应前缀。
• 核对Feign客户端配置：检查@FeignClient注解的服务名属性是否与注册中心中stock服务的注册名完全一致，检查注解path属性、方法上@GetMapping配置的路径是否与被调用方实际接口路径完全匹配，注意SpringMVC默认路径大小写敏感，禁止出现大小写拼写偏差。
• 核对注册中心实例清单：确认stock-Api服务名下注册的所有实例均为预期的stock服务，无其他无关服务注册到该服务名，避免Feign负载均衡时将请求转发至无对应接口的异常实例。
• 适配上下文路径规则：SpringCloud 2020.0之前的版本，Feign默认不会自动读取被调用服务配置的context-path，需手动在@FeignClient的path属性中补充对应前缀，或开启相关适配配置项。

内容的提问来源于stack exchange，提问作者Sanjay Kumar