/*
* Copyright 2011 The Netty Project
*
* The Netty Project 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 io.netty.handler.traffic;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufHolder;
import io.netty.channel.ChannelDuplexHandler;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPromise;
import io.netty.util.Attribute;
import io.netty.util.AttributeKey;
import java.util.concurrent.TimeUnit;
/**
* AbstractTrafficShapingHandler allows to limit the global bandwidth
* (see {@link GlobalTrafficShapingHandler}) or per session
* bandwidth (see {@link ChannelTrafficShapingHandler}), as traffic shaping.
* It allows you to implement an almost real time monitoring of the bandwidth using
* the monitors from {@link TrafficCounter} that will call back every checkInterval
* the method doAccounting of this handler.<br>
* <br>
*
* If you want for any particular reasons to stop the monitoring (accounting) or to change
* the read/write limit or the check interval, several methods allow that for you:<br>
* <ul>
* <li><tt>configure</tt> allows you to change read or write limits, or the checkInterval</li>
* <li><tt>getTrafficCounter</tt> allows you to have access to the TrafficCounter and so to stop
* or start the monitoring, to change the checkInterval directly, or to have access to its values.</li>
* </ul>
*/
public abstract class AbstractTrafficShapingHandler extends ChannelDuplexHandler {
/**
* Default delay between two checks: 1s
*/
public static final long DEFAULT_CHECK_INTERVAL = 1000;
/**
* Default minimal time to wait
*/
private static final long MINIMAL_WAIT = 10;
/**
* Traffic Counter
*/
protected TrafficCounter trafficCounter;
/**
* Limit in B/s to apply to write
*/
private long writeLimit;
/**
* Limit in B/s to apply to read
*/
private long readLimit;
/**
* Delay between two performance snapshots
*/
protected long checkInterval = DEFAULT_CHECK_INTERVAL; // default 1 s
private static final AttributeKey<Boolean> READ_SUSPENDED = AttributeKey.valueOf(
AbstractTrafficShapingHandler.class.getName() + ".READ_SUSPENDED");
private static final AttributeKey<Runnable> REOPEN_TASK = AttributeKey.valueOf(
AbstractTrafficShapingHandler.class.getName() + ".REOPEN_TASK");
/**
*
* @param newTrafficCounter the TrafficCounter to set
*/
void setTrafficCounter(TrafficCounter newTrafficCounter) {
trafficCounter = newTrafficCounter;
}
/**
* @param writeLimit
* 0 or a limit in bytes/s
* @param readLimit
* 0 or a limit in bytes/s
* @param checkInterval
* The delay between two computations of performances for
* channels or 0 if no stats are to be computed
*/
protected AbstractTrafficShapingHandler(long writeLimit, long readLimit,
long checkInterval) {
this.writeLimit = writeLimit;
this.readLimit = readLimit;
this.checkInterval = checkInterval;
}
/**
* Constructor using default Check Interval
*
* @param writeLimit
* 0 or a limit in bytes/s
* @param readLimit
* 0 or a limit in bytes/s
*/
protected AbstractTrafficShapingHandler(long writeLimit, long readLimit) {
this(writeLimit, readLimit, DEFAULT_CHECK_INTERVAL);
}
/**
* Constructor using NO LIMIT and default Check Interval
*/
protected AbstractTrafficShapingHandler() {
this(0, 0, DEFAULT_CHECK_INTERVAL);
}
/**
* Constructor using NO LIMIT
*
* @param checkInterval
* The delay between two computations of performances for
* channels or 0 if no stats are to be computed
*/
protected AbstractTrafficShapingHandler(long checkInterval) {
this(0, 0, checkInterval);
}
/**
* Change the underlying limitations and check interval.
*
* @param newWriteLimit The new write limit (in bytes)
* @param newReadLimit The new read limit (in bytes)
* @param newCheckInterval The new check interval (in milliseconds)
*/
public void configure(long newWriteLimit, long newReadLimit,
long newCheckInterval) {
configure(newWriteLimit, newReadLimit);
configure(newCheckInterval);
}
/**
* Change the underlying limitations.
*
* @param newWriteLimit The new write limit (in bytes)
* @param newReadLimit The new read limit (in bytes)
*/
public void configure(long newWriteLimit, long newReadLimit) {
writeLimit = newWriteLimit;
readLimit = newReadLimit;
if (trafficCounter != null) {
trafficCounter.resetAccounting(System.currentTimeMillis() + 1);
}
}
/**
* Change the check interval.
*
* @param newCheckInterval The new check interval (in milliseconds)
*/
public void configure(long newCheckInterval) {
checkInterval = newCheckInterval;
if (trafficCounter != null) {
trafficCounter.configure(checkInterval);
}
}
/**
* Called each time the accounting is computed from the TrafficCounters.
* This method could be used for instance to implement almost real time accounting.
*
* @param counter
* the TrafficCounter that computes its performance
*/
@SuppressWarnings("unused")
protected void doAccounting(TrafficCounter counter) {
// NOOP by default
}
/**
* Class to implement setReadable at fix time
*/
private static final class ReopenReadTimerTask implements Runnable {
final ChannelHandlerContext ctx;
ReopenReadTimerTask(ChannelHandlerContext ctx) {
this.ctx = ctx;
}
@Override
public void run() {
ctx.attr(READ_SUSPENDED).set(false);
ctx.read();
}
}
/**
* @return the time that should be necessary to wait to respect limit. Can be negative time
*/
private static long getTimeToWait(long limit, long bytes, long lastTime, long curtime) {
long interval = curtime - lastTime;
if (interval <= 0) {
// Time is too short, so just lets continue
return 0;
}
return (bytes * 1000 / limit - interval) / 10 * 10;
}
@Override
public void channelRead(final ChannelHandlerContext ctx, final Object msg) throws Exception {
long size = calculateSize(msg);
long curtime = System.currentTimeMillis();
if (trafficCounter != null) {
trafficCounter.bytesRecvFlowControl(size);
if (readLimit == 0) {
// no action
ctx.fireChannelRead(msg);
return;
}
// compute the number of ms to wait before reopening the channel
long wait = getTimeToWait(readLimit,
trafficCounter.currentReadBytes(),
trafficCounter.lastTime(), curtime);
if (wait >= MINIMAL_WAIT) { // At least 10ms seems a minimal
// time in order to
// try to limit the traffic
if (!isSuspended(ctx)) {
ctx.attr(READ_SUSPENDED).set(true);
// Create a Runnable to reactive the read if needed. If one was create before it will just be
// reused to limit object creation
Attribute<Runnable> attr = ctx.attr(REOPEN_TASK);
Runnable reopenTask = attr.get();
if (reopenTask == null) {
reopenTask = new ReopenReadTimerTask(ctx);
attr.set(reopenTask);
}
ctx.executor().schedule(reopenTask, wait,
TimeUnit.MILLISECONDS);
} else {
// Create a Runnable to update the next handler in the chain. If one was create before it will
// just be reused to limit object creation
Runnable bufferUpdateTask = new Runnable() {
@Override
public void run() {
ctx.fireChannelRead(msg);
}
};
ctx.executor().schedule(bufferUpdateTask, wait, TimeUnit.MILLISECONDS);
return;
}
}
}
ctx.fireChannelRead(msg);
}
@Override
public void read(ChannelHandlerContext ctx) {
if (!isSuspended(ctx)) {
ctx.read();
}
}
private static boolean isSuspended(ChannelHandlerContext ctx) {
Boolean suspended = ctx.attr(READ_SUSPENDED).get();
if (suspended == null || Boolean.FALSE.equals(suspended)) {
return false;
}
return true;
}
@Override
public void write(final ChannelHandlerContext ctx, final Object msg, final ChannelPromise promise)
throws Exception {
long curtime = System.currentTimeMillis();
long size = calculateSize(msg);
if (size > -1 && trafficCounter != null) {
trafficCounter.bytesWriteFlowControl(size);
if (writeLimit == 0) {
ctx.write(msg, promise);
return;
}
// compute the number of ms to wait before continue with the
// channel
long wait = getTimeToWait(writeLimit,
trafficCounter.currentWrittenBytes(),
trafficCounter.lastTime(), curtime);
if (wait >= MINIMAL_WAIT) {
ctx.executor().schedule(new Runnable() {
@Override
public void run() {
ctx.write(msg, promise);
}
}, wait, TimeUnit.MILLISECONDS);
return;
}
}
ctx.write(msg, promise);
}
/**
*
* @return the current TrafficCounter (if
* channel is still connected)
*/
public TrafficCounter trafficCounter() {
return trafficCounter;
}
@Override
public String toString() {
return "TrafficShaping with Write Limit: " + writeLimit +
" Read Limit: " + readLimit + " and Counter: " +
(trafficCounter != null? trafficCounter.toString() : "none");
}
/**
* Calculate the size of the given {@link Object}.
*
* This implementation supports {@link ByteBuf} and {@link ByteBufHolder}. Sub-classes may override this.
* @param msg the msg for which the size should be calculated
* @return size the size of the msg or {@code -1} if unknown.
*/
protected long calculateSize(Object msg) {
if (msg instanceof ByteBuf) {
return ((ByteBuf) msg).readableBytes();
}
if (msg instanceof ByteBufHolder) {
return ((ByteBufHolder) msg).content().readableBytes();
}
return -1;
}
}