gaoyunhaii commented on a change in pull request #7368: [FLINK-10742][network] Let Netty use Flink's buffers directly in credit-based mode URL: https://github.com/apache/flink/pull/7368#discussion_r381632755
########## File path: flink-runtime/src/main/java/org/apache/flink/runtime/io/network/netty/NettyMessageClientDecoder.java ########## @@ -0,0 +1,143 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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 org.apache.flink.runtime.io.network.netty; + +import org.apache.flink.runtime.io.network.NetworkClientHandler; +import org.apache.flink.shaded.netty4.io.netty.buffer.ByteBuf; +import org.apache.flink.shaded.netty4.io.netty.channel.ChannelHandlerContext; +import org.apache.flink.shaded.netty4.io.netty.channel.ChannelInboundHandlerAdapter; + +import static org.apache.flink.runtime.io.network.netty.NettyMessage.FRAME_HEADER_LENGTH; +import static org.apache.flink.runtime.io.network.netty.NettyMessage.MAGIC_NUMBER; +import static org.apache.flink.util.Preconditions.checkState; + +/** + * Decodes messages from the fragmentary netty buffers. This decoder assumes the + * messages have the following format: + * +-----------------------------------+--------------------------------+ + * | FRAME_HEADER || MESSAGE_HEADER | DATA BUFFER (Optional) | + * +-----------------------------------+--------------------------------+ + * + * This decoder decodes the frame header and delegates the other following work + * to corresponding message parsers according to the message type. During the process + * of decoding, the decoder and parsers try best to eliminate copying. For the frame + * header and message header, it only cumulates data when they span multiple input buffers. + * For the buffer part, it copies directly to the input channels to avoid future copying. + * + * The format of the frame header is + * +------------------+------------------+--------+ + * | FRAME LENGTH (4) | MAGIC NUMBER (4) | ID (1) | + * +------------------+------------------+--------+ + */ +public class NettyMessageClientDecoder extends ChannelInboundHandlerAdapter { + + /** The message parser for buffer response. */ + private final NettyMessageDecoderDelegate bufferResponseDecoderDelegate; + + /** The message parser for other messages other than buffer response. */ + private final NettyMessageDecoderDelegate nonBufferResponseDecoderDelegate; + + /** The cumulation buffer for the frame header part. */ + private ByteBuf frameHeaderBuffer; + + /** + * The chosen message parser for the current message. If it is null, then + * we are decoding the frame header part, otherwise we are decoding the actual + * message. + */ + private NettyMessageDecoderDelegate currentDecoderDelegate; + + NettyMessageClientDecoder(NetworkClientHandler networkClientHandler) { + this.bufferResponseDecoderDelegate = new BufferResponseDecoderDelegate(networkClientHandler); + this.nonBufferResponseDecoderDelegate = new NonBufferResponseDecoderDelegate(); + } + + @Override + public void channelActive(ChannelHandlerContext ctx) throws Exception { + super.channelActive(ctx); + + bufferResponseDecoderDelegate.onChannelActive(ctx.alloc()); + nonBufferResponseDecoderDelegate.onChannelActive(ctx.alloc()); + + frameHeaderBuffer = ctx.alloc().directBuffer(FRAME_HEADER_LENGTH); + } + + @Override + public void channelInactive(ChannelHandlerContext ctx) throws Exception { Review comment: I think it might be ok to not deal with `exceptionCaught` explicitly, since `channelInactive` is called when channel get closed, and in `CreditBasedPartitionClientHander`, it closes the channel in `exceptionCaught`, thus it will close the channel. Besides, I think we should always be able to close the channel, otherwise we should have channel leakage problem. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
