com.streamsets.pipeline.lib.udp.PacketQueueUDPHandler.java Source code

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Here is the source code for com.streamsets.pipeline.lib.udp.PacketQueueUDPHandler.java

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/*
 * Copyright 2017 StreamSets Inc.
 *
 * 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 com.streamsets.pipeline.lib.udp;

import io.netty.channel.ChannelHandler;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.channel.socket.DatagramPacket;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Map;
import java.util.concurrent.BlockingDeque;
import java.util.concurrent.LinkedBlockingDeque;
import java.util.concurrent.atomic.AtomicLong;

@ChannelHandler.Sharable
public class PacketQueueUDPHandler extends SimpleChannelInboundHandler<DatagramPacket> {
    private static final Logger LOG = LoggerFactory.getLogger(PacketQueueUDPHandler.class);

    public static final String GAUGE_PACKET_QUEUE_SIZE = "Queue Size";
    public static final String GAUGE_NUM_DROPPED_PACKETS = "Dropped Packets";
    public static final String GAUGE_NUM_QUEUED_PACKETS = "Queued Packets";

    private final Map<String, Object> gaugeMap;
    private AtomicLong droppedPacketCount = new AtomicLong();
    private AtomicLong queuedPacketCount = new AtomicLong();

    private final BlockingDeque<DatagramPacket> queue;

    public PacketQueueUDPHandler(Map<String, Object> gaugeMap, int packetQueueSize) {
        this.gaugeMap = gaugeMap;

        queue = new LinkedBlockingDeque<>(packetQueueSize);
    }

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) {
        ctx.flush();
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
        String msg = "Uncaught throwable in UDP Server: " + cause;
        LOG.error(msg, cause);
    }

    @Override
    protected void channelRead0(ChannelHandlerContext ctx, DatagramPacket packet) throws Exception {
        packet.retain();
        final boolean succeeded = queue.offer(packet);
        if (succeeded) {
            gaugeMap.put(GAUGE_NUM_QUEUED_PACKETS, queuedPacketCount.incrementAndGet());
            gaugeMap.put(GAUGE_PACKET_QUEUE_SIZE, queue.size());
        } else {
            gaugeMap.put(GAUGE_NUM_DROPPED_PACKETS, droppedPacketCount.incrementAndGet());
            // allow Netty to collect the buffer
            packet.release();
        }
    }

    public BlockingDeque<DatagramPacket> getPacketQueue() {
        return queue;
    }
}