com.ebay.jetstream.messaging.transport.netty.compression.MessageCompressionHandler.java Source code

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Here is the source code for com.ebay.jetstream.messaging.transport.netty.compression.MessageCompressionHandler.java

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/*******************************************************************************
 *  Copyright  2012-2015 eBay Software Foundation
 *  This program is dual licensed under the MIT and Apache 2.0 licenses.
 *  Please see LICENSE for more information.
 *******************************************************************************/
package com.ebay.jetstream.messaging.transport.netty.compression;

import io.netty.buffer.ByteBuf;
import io.netty.channel.Channel;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelOutboundHandlerAdapter;
import io.netty.channel.ChannelPromise;
import io.netty.util.Attribute;

import java.io.IOException;
import java.io.UnsupportedEncodingException;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.xerial.snappy.Snappy;

import com.ebay.jetstream.counter.LongCounter;
import com.ebay.jetstream.messaging.transport.netty.eventproducer.EventProducer;
import com.ebay.jetstream.messaging.transport.netty.eventproducer.ExtendedChannelPromise;
import com.ebay.jetstream.xmlser.XSerializable;

public class MessageCompressionHandler extends ChannelOutboundHandlerAdapter implements XSerializable {

    private static final Logger LOGGER = LoggerFactory.getLogger("com.ebay.jetstream.messaging");
    private LongCounter m_totalMessagesCompressed = new LongCounter();
    private LongCounter m_totalMessagesDropped = new LongCounter();

    public MessageCompressionHandler() {
    }

    /**
     * Invoked when {@link Channel#write(Object)} is called.
     */
    public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {

        try {

            Attribute<Boolean> attr = ctx.channel().attr(EventProducer.m_eckey);

            Boolean enableCompression = attr.get();

            if ((enableCompression != null) && (enableCompression == true)) {

                ByteBuf chbuf = (ByteBuf) msg;

                int msglen = chbuf.readableBytes();
                ExtendedChannelPromise epromise = (ExtendedChannelPromise) promise;
                epromise.setRawBytes(msglen);

                byte[] compressed = Snappy.rawCompress(chbuf.readBytes(msglen).array(), msglen);

                epromise.setCompressedBytes(compressed.length + 4);
                chbuf.release(); // need to release the original buffer - do I need to check if this this a ref counted buffer

                ByteBuf sendbuf = ctx.alloc().buffer();

                sendbuf.writeInt(compressed.length);
                sendbuf.writeBytes(compressed);

                ctx.write(sendbuf, promise);

                m_totalMessagesCompressed.increment();

            } else {

                ctx.write(msg, promise);

            }

        } catch (Throwable t) {
            m_totalMessagesDropped.increment();
            LOGGER.debug("Failed to compress message - " + t.getLocalizedMessage());

        }

    }

    /**
     * Call this method during init of app - the first call to snappy will take a few secs which will cause event loss if this is
     * not called early on.
     */
    public static void initSnappy() {

        byte[] compressed = null;
        long startTime = System.currentTimeMillis();

        try {

            String testMsg = "test";

            compressed = Snappy.rawCompress(testMsg.getBytes(), testMsg.length());

        } catch (UnsupportedEncodingException e) {

            LOGGER.error("failed to compress using Snappy - " + e.toString());

        } catch (IOException e) {
            LOGGER.error("failed to compress using Snappy - " + e.toString());

        }

        byte[] uncompressed = new byte[100];

        int len = 0;

        try {
            len = Snappy.rawUncompress(compressed, 0, compressed.length, uncompressed, 0);
        } catch (Throwable t) {
            LOGGER.error("failed to uncompress using Snappy - " + t.toString());

        }

    }

}