com.github.sparkfy.network.server.TransportChannelHandler.java Source code

Java tutorial

Introduction

Here is the source code for com.github.sparkfy.network.server.TransportChannelHandler.java

Source

/*
 * 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 com.github.sparkfy.network.server;

import com.github.sparkfy.network.client.TransportClient;
import com.github.sparkfy.network.client.TransportResponseHandler;
import com.github.sparkfy.network.protocol.Message;
import com.github.sparkfy.network.protocol.RequestMessage;
import com.github.sparkfy.network.protocol.ResponseMessage;
import com.github.sparkfy.network.util.NettyUtils;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.timeout.IdleState;
import io.netty.handler.timeout.IdleStateEvent;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * The single Transport-level Channel handler which is used for delegating requests to the
 * {@link TransportRequestHandler} and responses to the {@link TransportResponseHandler}.
 *
 * All channels created in the transport layer are bidirectional. When the Client initiates a Netty
 * Channel with a RequestMessage (which gets handled by the Server's RequestHandler), the Server
 * will produce a ResponseMessage (handled by the Client's ResponseHandler). However, the Server
 * also gets a handle on the same Channel, so it may then begin to send RequestMessages to the
 * Client.
 * This means that the Client also needs a RequestHandler and the Server needs a ResponseHandler,
 * for the Client's responses to the Server's requests.
 *
 * This class also handles timeouts from a {@link io.netty.handler.timeout.IdleStateHandler}.
 * We consider a connection timed out if there are outstanding fetch or RPC requests but no traffic
 * on the channel for at least `requestTimeoutMs`. Note that this is duplex traffic; we will not
 * timeout if the client is continuously sending but getting no responses, for simplicity.
 */
public class TransportChannelHandler extends SimpleChannelInboundHandler<Message> {
    private final Logger logger = LoggerFactory.getLogger(TransportChannelHandler.class);

    private final TransportClient client;
    private final TransportResponseHandler responseHandler;
    private final TransportRequestHandler requestHandler;
    private final long requestTimeoutNs;
    private final boolean closeIdleConnections;

    public TransportChannelHandler(TransportClient client, TransportResponseHandler responseHandler,
            TransportRequestHandler requestHandler, long requestTimeoutMs, boolean closeIdleConnections) {
        this.client = client;
        this.responseHandler = responseHandler;
        this.requestHandler = requestHandler;
        this.requestTimeoutNs = requestTimeoutMs * 1000L * 1000;
        this.closeIdleConnections = closeIdleConnections;
    }

    public TransportClient getClient() {
        return client;
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        logger.warn("Exception in connection from " + NettyUtils.getRemoteAddress(ctx.channel()), cause);
        requestHandler.exceptionCaught(cause);
        responseHandler.exceptionCaught(cause);
        ctx.close();
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        try {
            requestHandler.channelActive();
        } catch (RuntimeException e) {
            logger.error("Exception from request handler while registering channel", e);
        }
        try {
            responseHandler.channelActive();
        } catch (RuntimeException e) {
            logger.error("Exception from response handler while registering channel", e);
        }
        super.channelRegistered(ctx);
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        try {
            requestHandler.channelInactive();
        } catch (RuntimeException e) {
            logger.error("Exception from request handler while unregistering channel", e);
        }
        try {
            responseHandler.channelInactive();
        } catch (RuntimeException e) {
            logger.error("Exception from response handler while unregistering channel", e);
        }
        super.channelUnregistered(ctx);
    }

    @Override
    public void channelRead0(ChannelHandlerContext ctx, Message request) throws Exception {
        if (request instanceof RequestMessage) {
            requestHandler.handle((RequestMessage) request);
        } else {
            responseHandler.handle((ResponseMessage) request);
        }
    }

    /** Triggered based on events from an {@link io.netty.handler.timeout.IdleStateHandler}. */
    @Override
    public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
        if (evt instanceof IdleStateEvent) {
            IdleStateEvent e = (IdleStateEvent) evt;
            // See class comment for timeout semantics. In addition to ensuring we only timeout while
            // there are outstanding requests, we also do a secondary consistency check to ensure
            // there's no race between the idle timeout and incrementing the numOutstandingRequests
            // (see SPARK-7003).
            //
            // To avoid a race between TransportClientFactory.createClient() and this code which could
            // result in an inactive client being returned, this needs to run in a synchronized block.
            synchronized (this) {
                boolean isActuallyOverdue = System.nanoTime()
                        - responseHandler.getTimeOfLastRequestNs() > requestTimeoutNs;
                if (e.state() == IdleState.ALL_IDLE && isActuallyOverdue) {
                    if (responseHandler.numOutstandingRequests() > 0) {
                        String address = NettyUtils.getRemoteAddress(ctx.channel());
                        logger.error("Connection to {} has been quiet for {} ms while there are outstanding "
                                + "requests. Assuming connection is dead; please adjust spark.network.timeout if this "
                                + "is wrong.", address, requestTimeoutNs / 1000 / 1000);
                        client.timeOut();
                        ctx.close();
                    } else if (closeIdleConnections) {
                        // While CloseIdleConnections is enable, we also close idle connection
                        client.timeOut();
                        ctx.close();
                    }
                }
            }
        }
        ctx.fireUserEventTriggered(evt);
    }

    public TransportResponseHandler getResponseHandler() {
        return responseHandler;
    }

}