api/src/main/java/io/grpc/StreamTracer.java

/*
 * Copyright 2017 The gRPC Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package io.grpc;

import javax.annotation.concurrent.ThreadSafe;

/**
 * Listens to events on a stream to collect metrics.
 *
 * <p>DO NOT MOCK: Use TestStreamTracer. Mocks are not thread-safe
 */
@ExperimentalApi("https://github.com/grpc/grpc-java/issues/2861")
@ThreadSafe
public abstract class StreamTracer {
  /**
   * Stream is closed.  This will be called exactly once.
   */
  public void streamClosed(Status status) {
  }

  /**
   * An outbound message has been passed to the stream.  This is called as soon as the stream knows
   * about the message, but doesn't have further guarantee such as whether the message is serialized
   * or not.
   *
   * @param seqNo the sequential number of the message within the stream, starting from 0.  It can
   *              be used to correlate with {@link #outboundMessageSent} for the same message.
   */
  public void outboundMessage(int seqNo) {
  }

  /**
   * An inbound message has been received by the stream.  This is called as soon as the stream knows
   * about the message, but doesn't have further guarantee such as whether the message is
   * deserialized or not.
   *
   * @param seqNo the sequential number of the message within the stream, starting from 0.  It can
   *              be used to correlate with {@link #inboundMessageRead} for the same message.
   */
  public void inboundMessage(int seqNo) {
  }

  /**
   * An outbound message has been serialized and sent to the transport.
   *
   * @param seqNo the sequential number of the message within the stream, starting from 0.  It can
   *              be used to correlate with {@link #outboundMessage(int)} for the same message.
   * @param optionalWireSize the wire size of the message. -1 if unknown
   * @param optionalUncompressedSize the uncompressed serialized size of the message. -1 if unknown
   */
  public void outboundMessageSent(int seqNo, long optionalWireSize, long optionalUncompressedSize) {
  }

  /**
   * An inbound message has been fully read from the transport.
   *
   * @param seqNo the sequential number of the message within the stream, starting from 0.  It can
   *              be used to correlate with {@link #inboundMessage(int)} for the same message.
   * @param optionalWireSize the wire size of the message. -1 if unknown
   * @param optionalUncompressedSize the uncompressed serialized size of the message. -1 if unknown
   */
  public void inboundMessageRead(int seqNo, long optionalWireSize, long optionalUncompressedSize) {
  }

  /**
   * The wire size of some outbound data is revealed. This can only used to record the accumulative
   * outbound wire size. There is no guarantee wrt timing or granularity of this method.
   */
  public void outboundWireSize(long bytes) {
  }

  /**
   * The uncompressed size of some outbound data is revealed. This can only used to record the
   * accumulative outbound uncompressed size. There is no guarantee wrt timing or granularity of
   * this method.
   */
  public void outboundUncompressedSize(long bytes) {
  }

  /**
   * The wire size of some inbound data is revealed. This can only be used to record the
   * accumulative received wire size. There is no guarantee wrt timing or granularity of this
   * method.
   */
  public void inboundWireSize(long bytes) {
  }

  /**
   * The uncompressed size of some inbound data is revealed. This can only used to record the
   * accumulative received uncompressed size. There is no guarantee wrt timing or granularity of
   * this method.
   */
  public void inboundUncompressedSize(long bytes) {
  }
}