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JDBC Driver for Google Cloud Spanner
/*
* Copyright 2012 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 nl.topicus.jdbc.shaded.io.netty.handler.traffic;
import nl.topicus.jdbc.shaded.io.netty.buffer.ByteBuf;
import nl.topicus.jdbc.shaded.io.netty.channel.ChannelHandler.Sharable;
import nl.topicus.jdbc.shaded.io.netty.channel.Channel;
import nl.topicus.jdbc.shaded.io.netty.channel.ChannelHandlerContext;
import nl.topicus.jdbc.shaded.io.netty.channel.ChannelPromise;
import nl.topicus.jdbc.shaded.io.netty.util.concurrent.EventExecutor;
import nl.topicus.jdbc.shaded.io.netty.util.internal.PlatformDependent;
import java.util.ArrayDeque;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;
/**
* This implementation of the {@link AbstractTrafficShapingHandler} is for global
* traffic shaping, that is to say a global limitation of the bandwidth, whatever
* the number of opened channels.
* Note the index used in {@code OutboundBuffer.setUserDefinedWritability(index, boolean)} is 2.
*
* The general use should be as follow:
*
* Create your unique GlobalTrafficShapingHandler like:
* GlobalTrafficShapingHandler myHandler = new GlobalTrafficShapingHandler(executor);
* The executor could be the underlying IO worker pool
* pipeline.addLast(myHandler);
*
* Note that this handler has a Pipeline Coverage of "all" which means only one such handler must be created
* and shared among all channels as the counter must be shared among all channels.
*
* Other arguments can be passed like write or read limitation (in bytes/s where 0 means no limitation)
* or the check interval (in millisecond) that represents the delay between two computations of the
* bandwidth and so the call back of the doAccounting method (0 means no accounting at all).
*
* A value of 0 means no accounting for checkInterval. If you need traffic shaping but no such accounting,
* it is recommended to set a positive value, even if it is high since the precision of the
* Traffic Shaping depends on the period where the traffic is computed. The highest the interval,
* the less precise the traffic shaping will be. It is suggested as higher value something close
* to 5 or 10 minutes.
*
* maxTimeToWait, by default set to 15s, allows to specify an upper bound of time shaping.
* - In your handler, you should consider to use the {@code channel.isWritable()} and
* {@code channelWritabilityChanged(ctx)} to handle writability, or through
* {@code future.addListener(new GenericFutureListener())} on the future returned by
* {@code ctx.write()}.
* You shall also consider to have object size in read or write operations relatively adapted to
* the bandwidth you required: for instance having 10 MB objects for 10KB/s will lead to burst effect,
* while having 100 KB objects for 1 MB/s should be smoothly handle by this TrafficShaping handler.
Some configuration methods will be taken as best effort, meaning
* that all already scheduled traffics will not be
* changed, but only applied to new traffics.
* So the expected usage of those methods are to be used not too often,
* accordingly to the traffic shaping configuration.
*
* Be sure to call {@link #release()} once this handler is not needed anymore to release all internal resources.
* This will not shutdown the {@link EventExecutor} as it may be shared, so you need to do this by your own.
*/
@Sharable
public class GlobalTrafficShapingHandler extends AbstractTrafficShapingHandler {
/**
* All queues per channel
*/
private final ConcurrentMap channelQueues = PlatformDependent.newConcurrentHashMap();
/**
* Global queues size
*/
private final AtomicLong queuesSize = new AtomicLong();
/**
* Max size in the list before proposing to stop writing new objects from next handlers
* for all channel (global)
*/
long maxGlobalWriteSize = DEFAULT_MAX_SIZE * 100; // default 400MB
private static final class PerChannel {
ArrayDeque messagesQueue;
long queueSize;
long lastWriteTimestamp;
long lastReadTimestamp;
}
/**
* Create the global TrafficCounter.
*/
void createGlobalTrafficCounter(ScheduledExecutorService executor) {
if (executor == null) {
throw new NullPointerException("executor");
}
TrafficCounter tc = new TrafficCounter(this, executor, "GlobalTC", checkInterval);
setTrafficCounter(tc);
tc.start();
}
@Override
protected int userDefinedWritabilityIndex() {
return AbstractTrafficShapingHandler.GLOBAL_DEFAULT_USER_DEFINED_WRITABILITY_INDEX;
}
/**
* Create a new instance.
*
* @param executor
* the {@link ScheduledExecutorService} to use for the {@link TrafficCounter}.
* @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.
* @param maxTime
* The maximum delay to wait in case of traffic excess.
*/
public GlobalTrafficShapingHandler(ScheduledExecutorService executor, long writeLimit, long readLimit,
long checkInterval, long maxTime) {
super(writeLimit, readLimit, checkInterval, maxTime);
createGlobalTrafficCounter(executor);
}
/**
* Create a new instance using
* default max time as delay allowed value of 15000 ms.
*
* @param executor
* the {@link ScheduledExecutorService} to use for the {@link TrafficCounter}.
* @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.
*/
public GlobalTrafficShapingHandler(ScheduledExecutorService executor, long writeLimit,
long readLimit, long checkInterval) {
super(writeLimit, readLimit, checkInterval);
createGlobalTrafficCounter(executor);
}
/**
* Create a new instance using default Check Interval value of 1000 ms and
* default max time as delay allowed value of 15000 ms.
*
* @param executor
* the {@link ScheduledExecutorService} to use for the {@link TrafficCounter}.
* @param writeLimit
* 0 or a limit in bytes/s
* @param readLimit
* 0 or a limit in bytes/s
*/
public GlobalTrafficShapingHandler(ScheduledExecutorService executor, long writeLimit,
long readLimit) {
super(writeLimit, readLimit);
createGlobalTrafficCounter(executor);
}
/**
* Create a new instance using
* default max time as delay allowed value of 15000 ms and no limit.
*
* @param executor
* the {@link ScheduledExecutorService} to use for the {@link TrafficCounter}.
* @param checkInterval
* The delay between two computations of performances for
* channels or 0 if no stats are to be computed.
*/
public GlobalTrafficShapingHandler(ScheduledExecutorService executor, long checkInterval) {
super(checkInterval);
createGlobalTrafficCounter(executor);
}
/**
* Create a new instance using default Check Interval value of 1000 ms and
* default max time as delay allowed value of 15000 ms and no limit.
*
* @param executor
* the {@link ScheduledExecutorService} to use for the {@link TrafficCounter}.
*/
public GlobalTrafficShapingHandler(EventExecutor executor) {
createGlobalTrafficCounter(executor);
}
/**
* @return the maxGlobalWriteSize default value being 400 MB.
*/
public long getMaxGlobalWriteSize() {
return maxGlobalWriteSize;
}
/**
* Note the change will be taken as best effort, meaning
* that all already scheduled traffics will not be
* changed, but only applied to new traffics.
* So the expected usage of this method is to be used not too often,
* accordingly to the traffic shaping configuration.
*
* @param maxGlobalWriteSize the maximum Global Write Size allowed in the buffer
* globally for all channels before write suspended is set,
* default value being 400 MB.
*/
public void setMaxGlobalWriteSize(long maxGlobalWriteSize) {
this.maxGlobalWriteSize = maxGlobalWriteSize;
}
/**
* @return the global size of the buffers for all queues.
*/
public long queuesSize() {
return queuesSize.get();
}
/**
* Release all internal resources of this instance.
*/
public final void release() {
trafficCounter.stop();
}
private PerChannel getOrSetPerChannel(ChannelHandlerContext ctx) {
// ensure creation is limited to one thread per channel
Channel channel = ctx.channel();
Integer key = channel.hashCode();
PerChannel perChannel = channelQueues.get(key);
if (perChannel == null) {
perChannel = new PerChannel();
perChannel.messagesQueue = new ArrayDeque();
perChannel.queueSize = 0L;
perChannel.lastReadTimestamp = TrafficCounter.milliSecondFromNano();
perChannel.lastWriteTimestamp = perChannel.lastReadTimestamp;
channelQueues.put(key, perChannel);
}
return perChannel;
}
@Override
public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
getOrSetPerChannel(ctx);
super.handlerAdded(ctx);
}
@Override
public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
Channel channel = ctx.channel();
Integer key = channel.hashCode();
PerChannel perChannel = channelQueues.remove(key);
if (perChannel != null) {
// write operations need synchronization
synchronized (perChannel) {
if (channel.isActive()) {
for (ToSend toSend : perChannel.messagesQueue) {
long size = calculateSize(toSend.toSend);
trafficCounter.bytesRealWriteFlowControl(size);
perChannel.queueSize -= size;
queuesSize.addAndGet(-size);
ctx.write(toSend.toSend, toSend.promise);
}
} else {
queuesSize.addAndGet(-perChannel.queueSize);
for (ToSend toSend : perChannel.messagesQueue) {
if (toSend.toSend instanceof ByteBuf) {
((ByteBuf) toSend.toSend).release();
}
}
}
perChannel.messagesQueue.clear();
}
}
releaseWriteSuspended(ctx);
releaseReadSuspended(ctx);
super.handlerRemoved(ctx);
}
@Override
long checkWaitReadTime(final ChannelHandlerContext ctx, long wait, final long now) {
Integer key = ctx.channel().hashCode();
PerChannel perChannel = channelQueues.get(key);
if (perChannel != null) {
if (wait > maxTime && now + wait - perChannel.lastReadTimestamp > maxTime) {
wait = maxTime;
}
}
return wait;
}
@Override
void informReadOperation(final ChannelHandlerContext ctx, final long now) {
Integer key = ctx.channel().hashCode();
PerChannel perChannel = channelQueues.get(key);
if (perChannel != null) {
perChannel.lastReadTimestamp = now;
}
}
private static final class ToSend {
final long relativeTimeAction;
final Object toSend;
final long size;
final ChannelPromise promise;
private ToSend(final long delay, final Object toSend, final long size, final ChannelPromise promise) {
relativeTimeAction = delay;
this.toSend = toSend;
this.size = size;
this.promise = promise;
}
}
@Override
void submitWrite(final ChannelHandlerContext ctx, final Object msg,
final long size, final long writedelay, final long now,
final ChannelPromise promise) {
Channel channel = ctx.channel();
Integer key = channel.hashCode();
PerChannel perChannel = channelQueues.get(key);
if (perChannel == null) {
// in case write occurs before handlerAdded is raised for this handler
// imply a synchronized only if needed
perChannel = getOrSetPerChannel(ctx);
}
final ToSend newToSend;
long delay = writedelay;
boolean globalSizeExceeded = false;
// write operations need synchronization
synchronized (perChannel) {
if (writedelay == 0 && perChannel.messagesQueue.isEmpty()) {
trafficCounter.bytesRealWriteFlowControl(size);
ctx.write(msg, promise);
perChannel.lastWriteTimestamp = now;
return;
}
if (delay > maxTime && now + delay - perChannel.lastWriteTimestamp > maxTime) {
delay = maxTime;
}
newToSend = new ToSend(delay + now, msg, size, promise);
perChannel.messagesQueue.addLast(newToSend);
perChannel.queueSize += size;
queuesSize.addAndGet(size);
checkWriteSuspend(ctx, delay, perChannel.queueSize);
if (queuesSize.get() > maxGlobalWriteSize) {
globalSizeExceeded = true;
}
}
if (globalSizeExceeded) {
setUserDefinedWritability(ctx, false);
}
final long futureNow = newToSend.relativeTimeAction;
final PerChannel forSchedule = perChannel;
ctx.executor().schedule(new Runnable() {
@Override
public void run() {
sendAllValid(ctx, forSchedule, futureNow);
}
}, delay, TimeUnit.MILLISECONDS);
}
private void sendAllValid(final ChannelHandlerContext ctx, final PerChannel perChannel, final long now) {
// write operations need synchronization
synchronized (perChannel) {
ToSend newToSend = perChannel.messagesQueue.pollFirst();
for (; newToSend != null; newToSend = perChannel.messagesQueue.pollFirst()) {
if (newToSend.relativeTimeAction <= now) {
long size = newToSend.size;
trafficCounter.bytesRealWriteFlowControl(size);
perChannel.queueSize -= size;
queuesSize.addAndGet(-size);
ctx.write(newToSend.toSend, newToSend.promise);
perChannel.lastWriteTimestamp = now;
} else {
perChannel.messagesQueue.addFirst(newToSend);
break;
}
}
if (perChannel.messagesQueue.isEmpty()) {
releaseWriteSuspended(ctx);
}
}
ctx.flush();
}
}