grpc java中的低级事件

Question

用例是，我们有一个单独的流和通道，我们通过它发送具有非常大的有效负载的消息。同时，我们也有一个应用程序级别的ping，如果我们在最后10秒内没有看到新的消息，它就会超时。在速度较慢的网络上，从流中读取数据需要花费大量时间。

当完整的消息被读取和反序列化时，我们从GRPC得到的唯一回调是onNext。有没有办法获取较低级别的事件，比如正在进行的流读取？或者是否有一种方法可以拦截流阅读器

public interface StreamObserver<V>  {
  /**
   * Receives a value from the stream.
   *
   * <p>Can be called many times but is never called after {@link #onError(Throwable)} or {@link
   * #onCompleted()} are called.
   *
   * <p>Unary calls must invoke onNext at most once.  Clients may invoke onNext at most once for
   * server streaming calls, but may receive many onNext callbacks.  Servers may invoke onNext at
   * most once for client streaming calls, but may receive many onNext callbacks.
   *
   * <p>If an exception is thrown by an implementation the caller is expected to terminate the
   * stream by calling {@link #onError(Throwable)} with the caught exception prior to
   * propagating it.
   *
   * @param value the value passed to the stream
   */
  void onNext(V value);

  /**
   * Receives a terminating error from the stream.
   *
   * <p>May only be called once and if called it must be the last method called. In particular if an
   * exception is thrown by an implementation of {@code onError} no further calls to any method are
   * allowed.
   *
   * <p>{@code t} should be a {@link io.grpc.StatusException} or {@link
   * io.grpc.StatusRuntimeException}, but other {@code Throwable} types are possible. Callers should
   * generally convert from a {@link io.grpc.Status} via {@link io.grpc.Status#asException()} or
   * {@link io.grpc.Status#asRuntimeException()}. Implementations should generally convert to a
   * {@code Status} via {@link io.grpc.Status#fromThrowable(Throwable)}.
   *
   * @param t the error occurred on the stream
   */
  void onError(Throwable t);

  /**
   * Receives a notification of successful stream completion.
   *
   * <p>May only be called once and if called it must be the last method called. In particular if an
   * exception is thrown by an implementation of {@code onCompleted} no further calls to any method
   * are allowed.
   */
  void onCompleted();
}

Answer 1

您可以添加ServerInterceptor或ServerStreamTracer.Factory来观察流事件。

或更改日志级别以获取所有事件的更多详细信息，如下所示：

    public static void main(String[] args) throws InterruptedException{
        setLogger("io.grpc");
    }
    
    private static void setLogger(String className) {
        Logger logger = Logger.getLogger(className);
        logger.setLevel(Level.ALL);

        ConsoleHandler handler = new ConsoleHandler();
        handler.setLevel(Level.ALL);
        logger.addHandler(handler);
    }

如果您希望使用logback打印日志，只需参考此文档：grpc-java-example#log