关于Eureka服务调用服务不通问题的查找

关于Eureka服务调用服务不通问题的查找

注明： 转载请注明转自 http://write.blog.csdn.net/mdeditor#!postId=59524361

1 .spring eureka相关的知识点请看该文章

2.本人所遇到的问题是关于eureka消费方调用服务端时服务抛出异常

 > com.netflix.hystrix.exception.HystrixRuntimeException: xxxxxxx time-out and no fallback available.

at com.netflix.hystrix.AbstractCommand$16.call(AbstractCommand.java:801)
at com.netflix.hystrix.AbstractCommand$16.call(AbstractCommand.java:785)
at rx.internal.operators.OperatorOnErrorResumeNextViaFunction$4.onError(OperatorOnErrorResumeNextViaFunction.java:139)
at rx.internal.operators.OperatorDoOnEach$1.onError(OperatorDoOnEach.java:71)
at rx.internal.operators.OperatorDoOnEach$1.onError(OperatorDoOnEach.java:71)
at rx.internal.operators.OperatorDoOnEach$1.onError(OperatorDoOnEach.java:71)
at com.netflix.hystrix.AbstractCommand$DeprecatedOnFallbackHookApplication$1.onError(AbstractCommand.java:1514)
at com.netflix.hystrix.AbstractCommand$FallbackHookApplication$1.onError(AbstractCommand.java:1404)
at com.netflix.hystrix.HystrixCommand$2.call(HystrixCommand.java:314)
at com.netflix.hystrix.HystrixCommand$2.call(HystrixCommand.java:306)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:50)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:50)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:50)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:50)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:50)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:50)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:50)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:50)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:50)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:50)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30)
at rx.Observable.unsafeSubscribe(Observable.java:8460)
at rx.internal.operators.OperatorOnErrorResumeNextViaFunction$4.onError(OperatorOnErrorResumeNextViaFunction.java:141)
at rx.internal.operators.OperatorDoOnEach$1.onError(OperatorDoOnEach.java:71)
at rx.internal.operators.OperatorDoOnEach$1.onError(OperatorDoOnEach.java:71)
at com.netflix.hystrix.AbstractCommand$HystrixObservableTimeoutOperator$3.onError(AbstractCommand.java:1005)
at rx.internal.operators.OperatorDoOnEach$1.onError(OperatorDoOnEach.java:71)
at rx.internal.operators.OperatorSubscribeOn$1$1.onError(OperatorSubscribeOn.java:59)
at rx.internal.operators.OperatorDoOnEach$1.onError(OperatorDoOnEach.java:71)
at com.netflix.hystrix.AbstractCommand$DeprecatedOnRunHookApplication$1.onError(AbstractCommand.java:1473)
at com.netflix.hystrix.AbstractCommand$ExecutionHookApplication$1.onError(AbstractCommand.java:1369)
at com.netflix.hystrix.HystrixCommand$1.call(HystrixCommand.java:297)
at com.netflix.hystrix.HystrixCommand$1.call(HystrixCommand.java:289)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:50)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:50)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:50)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30)
at rx.Observable.unsafeSubscribe(Observable.java:8460)
at com.netflix.hystrix.AbstractCommand$5.call(AbstractCommand.java:517)
at com.netflix.hystrix.AbstractCommand$5.call(AbstractCommand.java:495)
at rx.Observable.unsafeSubscribe(Observable.java:8460)
at rx.internal.operators.OperatorSubscribeOn$1.call(OperatorSubscribeOn.java:94)
at com.netflix.hystrix.strategy.concurrency.HystrixContexSchedulerAction$1.call(HystrixContexSchedulerAction.java:56)
at com.netflix.hystrix.strategy.concurrency.HystrixContexSchedulerAction$1.call(HystrixContexSchedulerAction.java:47)
at com.netflix.hystrix.strategy.concurrency.HystrixContexSchedulerAction.call(HystrixContexSchedulerAction.java:69)
at rx.internal.schedulers.ScheduledAction.run(ScheduledAction.java:55)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)

查看服务方rest api调用正常，暴漏的client 服务名正确，eureka 注册中心服务已经注册上去了，这些问题反复查看都正常之后本人怀疑时网络端配置有问题，所以进行源码debug;

设计相关的主要类： hystrix中的HystrixCommand 的类，HystrixCommand 继承AbstractCommand 类等，中间设计一系列的逻辑处理以及方法调用（这里不细说），最终http 请求调用是使用 feign core包中的 Client类 的 execute方法

@Override
public Response execute(Request request, Options options) throws IOException {
HttpURLConnection connection = convertAndSend(request, options);
return convertResponse(connection);
}

当debug到该方法时看到connection是不可用状态：

Response convertResponse(HttpURLConnection connection) throws IOException {
int status = connection.getResponseCode();
String reason = connection.getResponseMessage();

  if (status < 0) {
    throw new IOException(format("Invalid status(%s) executing %s %s", status,
        connection.getRequestMethod(), connection.getURL()));
  }

  Map> headers = new LinkedHashMap>();
  for (Map.Entry> field : connection.getHeaderFields().entrySet()) {
    // response message
    if (field.getKey() != null) {
      headers.put(field.getKey(), field.getValue());
    }
  }

  Integer length = connection.getContentLength();
  if (length == -1) {
    length = null;
  }
  InputStream stream;
  if (status >= 400) {
    stream = connection.getErrorStream();
  } else {
    stream = connection.getInputStream();
  }
  return Response.create(status, reason, headers, stream, length);
}

后面通过该connection中直接请求url发现域名不通，问题随即发现确实是nginx配置问题：

另：
eureka 会根据服务方的响应状态进行响应，如果服务方业务异常建议自己包装正常的response响应，以免eureka根据response code跑出异常不便消费者解析