解决FeignClient被FallBack后无错误日志打印问题
由于服务中@FeignClient指定了外部客户端接口的回退类fallback = UserApiHystrix.class，当触发接口异常或莫名进入到回退类方法时，无任何日志，无法定位具体问题。
解决方案一
通过配置文件中配置某个FeignClient服务接口日志级别，因为FeignClientsConfiguration中feignLoggerFactory方法默认日志实现类为feign.slf4j.Slf4jLogger 而日志打印之前会有logger.isDebugEnabled()判断，我们生产环境大部分配置的日志级别都为info，所以这里需要单独进行配置**.UserApi=debug。
# NONE，无记录（DEFAULT）。
# BASIC，只记录请求方法和URL以及响应状态代码和执行时间。
# HEADERS，记录基本信息以及请求和响应标头。
# FULL，记录请求和响应的头文件，正文和元数据。
feign.client.config.user-service.loggerLevel=BASIC
logging.level.com.feign.UserApi=debug
对应的FeignClient接口配置
@FeignClient(
name = "user-service",
fallback = UserApiHystrix.class
)
public interface UserApi {
}
我们再次请求接口，则会出现以下日志，可见是由于404导致执行了回退类方法
2022-07-06 15:24:37.948 DEBUG [localhost] 60421 --- [reakerFactory-1] [TID: N/A] c.UserApi : [UserApi#get] ---> GET http://localhost:8080/user-api/get HTTP/1.1
2022-07-06 15:24:38.146 DEBUG [localhost] 60421 --- [reakerFactory-1] [TID: N/A] c.UserApi : [UserApi#get] <--- HTTP/1.1 404 (198ms)
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解决方案二
通过@FeignClient中configuration设置某个服务日志级别等，对应的FeignClient接口配置如下
@FeignClient(
name = "user-service",
fallback = UserApiHystrix.class,
configuration = FeignConfiguration.class
)
public interface UserApi {
}
FeignConfiguration配置如下
import feign.Logger;
import feign.Request;
import feign.Response;
import lombok.extern.slf4j.Slf4j;
import org.springframework.context.annotation.Bean;
import java.io.IOException;
/**
* 〈Configuration〉
*
* @author 丁乾文
* @date 2022/7/6 12:39
* @since 1.0.0
*/
public class FeignConfiguration {
/**
* NONE，无记录（DEFAULT）。
* BASIC，只记录请求方法和URL以及响应状态代码和执行时间。
* HEADERS，记录基本信息以及请求和响应标头。
* FULL，记录请求和响应的头文件，正文和元数据。
*
* @return Level
*/
@Bean
Logger.Level feignLoggerLevel() {
return Logger.Level.BASIC;
}
@Bean
Logger feignLogger() {
return new FeignLogger();
}
}
@Slf4j
class FeignLogger extends feign.Logger {
@Override
protected void logRequest(String configKey, Level logLevel, Request request) {
if (log.isInfoEnabled()) {
super.logRequest(configKey, logLevel, request);
}
}
@Override
protected Response logAndRebufferResponse(String configKey, Level logLevel, Response response, long elapsedTime) throws IOException {
if (log.isInfoEnabled()) {
return super.logAndRebufferResponse(configKey, logLevel, response, elapsedTime);
}
return response;
}
@Override
protected void log(String configKey, String format, Object... args) {
if (log.isInfoEnabled()) {
log.info(String.format(methodTag(configKey) + format, args));
}
}
}
解决方案三
需要改变代码结构，@FeignClient中fallback改为使用fallbackFactory，例如
@FeignClient(
name = "user-service",
// fallback = UserApiHystrix.class,
fallbackFactory = UserApiFallBackFactory.class
)
public interface UserApi {
}
UserApiFallBackFactory代码实现如下
@Slf4j
@Component
public class UserApiFallBackFactory implements FallbackFactory<UserApi> {
@Override
public UserApi create(Throwable cause) {
log.info("UserApi Throwable", cause);
return new UserApi() {
@Override
public Response<UserData> get(@Valid Request<Param> request) {
return null;
}
};
}
}
再次请求，则会打印如下日志
2022-07-06 15:40:45.677 INFO [localhost] 67702 --- [reakerFactory-1] [TID: N/A] c.f.UserApiFallBackFactory : UserApi Throwable
feign.FeignException$NotFound: [404] during [GET] to [http://localhost:8080/user-api/get] [UserApi#get(Request)]: [{"timestamp":"2022-07-06T07:40:46.042+00:00","status":404,"error":"Not Found","path":"/user-api/get"}]
at feign.FeignException.clientErrorStatus(FeignException.java:219)
at feign.FeignException.errorStatus(FeignException.java:194)
at feign.FeignException.errorStatus(FeignException.java:185)
at feign.codec.ErrorDecoder$Default.decode(ErrorDecoder.java:92)
at feign.AsyncResponseHandler.handleResponse(AsyncResponseHandler.java:96)
at feign.SynchronousMethodHandler.executeAndDecode(SynchronousMethodHandler.java:138)
at feign.SynchronousMethodHandler.invoke(SynchronousMethodHandler.java:89)
at org.springframework.cloud.openfeign.FeignCircuitBreakerInvocationHandler.lambda$asSupplier$1(FeignCircuitBreakerInvocationHandler.java:112)
at org.springframework.cloud.netflix.hystrix.HystrixCircuitBreaker$1.run(HystrixCircuitBreaker.java:45)
at com.netflix.hystrix.HystrixCommand$2.call(HystrixCommand.java:302)
at com.netflix.hystrix.HystrixCommand$2.call(HystrixCommand.java:298)
at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:46)
at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:35)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30)
at rx.Observable.unsafeSubscribe(Observable.java:10327)
at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:51)
at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:35)
at rx.Observable.unsafeSubscribe(Observable.java:10327)
at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:41)
at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:30)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30)
at rx.Observable.unsafeSubscribe(Observable.java:10327)
at rx.internal.operators.OperatorSubscribeOn$SubscribeOnSubscriber.call(OperatorSubscribeOn.java:100)
at com.netflix.hystrix.strategy.concurrency.HystrixContexSchedulerAction$1.call(HystrixContexSchedulerAction.java:56)
at com.netflix.hystrix.strategy.concurrency.HystrixContexSchedulerAction$1.call(HystrixContexSchedulerAction.java:47)
at com.netflix.hystrix.strategy.concurrency.HystrixContexSchedulerAction.call(HystrixContexSchedulerAction.java:69)
at rx.internal.schedulers.ScheduledAction.run(ScheduledAction.java:55)
at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
at java.base/java.util.concurrent.FutureTask.run$$$capture(FutureTask.java:264)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
at java.base/java.lang.Thread.run(Thread.java:834)
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