Hystrix超时时间配置

2017-05-18

Hystrix

Hystrix配置整体的超时时间

hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds=1000

配置单个超时时间

hystrix.command.HystrixCommandKey.execution.isolation.thread.timeoutInMilliseconds=1000

其中HystrixCommandKey为@HystrixCommand 进行配置
example
@HystrixCommand(groupKey = "StoreSubmission", commandKey = "StoreSubmission", threadPoolKey = "StoreSubmission")
public String storeSubmission(ReturnType returnType, InputStream is, String id) {
}
@HystrixCommand需要引入依赖
<dependency>
	<groupId>com.netflix.hystrix</groupId>
	<artifactId>hystrix-javanica</artifactId>
	<version>${hystrix-version}</version>
</dependency>

配置参考stackoverflow

在fegin中配置超时时间

在fegin中无法使用@HystrixCommand来单独进行配置

1	hystrix.command.MyService#getLastTimeData(Map).execution.isolation.thread.timeoutInMilliseconds这种可以的，通过实践验证了 @甲申验证

配置原理

HystrixInvocationHandler

final class HystrixInvocationHandler implements InvocationHandler {
  private final Target<?> target;
  private final Map<Method, MethodHandler> dispatch;
  private final FallbackFactory<?> fallbackFactory; // Nullable
  private final Map<Method, Method> fallbackMethodMap;
  private final Map<Method, Setter> setterMethodMap;//时间配置
  
  
  static Map<Method, Setter> toSetters(SetterFactory setterFactory, Target<?> target,
                                       Set<Method> methods) {
    Map<Method, Setter> result = new LinkedHashMap<Method, Setter>();
    for (Method method : methods) {
      method.setAccessible(true);
      result.put(method, setterFactory.create(target, method));
    }
    return result;
  }

SetterFactory

public interface SetterFactory {
  /**
   * Returns a hystrix setter appropriate for the given target and method
   */
  HystrixCommand.Setter create(Target<?> target, Method method);
  /**
   * Default behavior is to derive the group key from {@link Target#name()} and the command key from
   * {@link Feign#configKey(Class, Method)}.
   */
  final class Default implements SetterFactory {
    @Override
    public HystrixCommand.Setter create(Target<?> target, Method method) {
      String groupKey = target.name();
      String commandKey = Feign.configKey(target.type(), method);
      return HystrixCommand.Setter
          .withGroupKey(HystrixCommandGroupKey.Factory.asKey(groupKey))
          .andCommandKey(HystrixCommandKey.Factory.asKey(commandKey));
    }
  }
}

fegin

public static String configKey(Class targetType, Method method) {
    StringBuilder builder = new StringBuilder();
    builder.append(targetType.getSimpleName());
    builder.append('#').append(method.getName()).append('(');
    for (Type param : method.getGenericParameterTypes()) {
      param = Types.resolve(targetType, targetType, param);
      builder.append(Types.getRawType(param).getSimpleName()).append(',');
    }
    if (method.getParameterTypes().length > 0) {
      builder.deleteCharAt(builder.length() - 1);
    }
    return builder.append(')').toString();
  }

对应上面的规则就可以解释了

1 2	hystrix.command.MyService#getLastTimeData(Map).execution.isolation.thread.timeoutInMilliseconds 其中MyService#getLastTimeData(Map)为commandKey有configKey进行生成

hystrix生效

HystrixInvocationHandler.invoke->
newHystrixCommand->execute->toObservable->
addTimerListener(executionTimeoutInMilliseconds)->
ScheduledThreadPoolExecutor.scheduleAtFixedRate-call-TimerListener.tick->
timeoutRunnable.run->throw HystrixTimeoutException 
简单来说就是创建一个ScheduledThreadPoolExecutor，超时时间后执行抛出异常操作，如果超时时间执行完成会吧这个Reference应用干掉

ps

群里看到的问题，闲顺便翻了下源码。有错误请指出，避免误人子弟