/*
* Copyright 2015 Netflix, 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 io.reactivex.netty.internal;
import io.netty.channel.ChannelDuplexHandler;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPromise;
import io.netty.handler.timeout.ReadTimeoutException;
import io.netty.handler.timeout.ReadTimeoutHandler;
import io.reactivex.netty.client.ClientConnectionToChannelBridge.PooledConnectionReleaseEvent;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
/**
* A copy of netty's {@link ReadTimeoutHandler}. This is required because {@link ReadTimeoutHandler} does not allow
* reuse in the same pipeline, which is required for connection pooling.
* See issue https://github.com/ReactiveX/RxNetty/issues/344
*/
public class InternalReadTimeoutHandler extends ChannelDuplexHandler {
private static final Logger logger = LoggerFactory.getLogger(InternalReadTimeoutHandler.class);
private static final long MIN_TIMEOUT_NANOS = TimeUnit.MILLISECONDS.toNanos(1);
private final long timeoutNanos;
private volatile ScheduledFuture<?> timeout;
private volatile long lastReadTime;
private enum State {
Created,
Active,
Paused,
Destroyed
}
private volatile State state = State.Created;
private boolean closed;
/**
* Creates a new instance.
*
* @param timeout
* read timeout
* @param unit
* the {@link TimeUnit} of {@code timeout}
*/
public InternalReadTimeoutHandler(long timeout, TimeUnit unit) {
if (unit == null) {
throw new NullPointerException("unit");
}
if (timeout <= 0) {
timeoutNanos = 0;
} else {
timeoutNanos = Math.max(unit.toNanos(timeout), MIN_TIMEOUT_NANOS);
}
}
@Override
public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
if (ctx.channel().isActive() && ctx.channel().isRegistered()) {
// channelActive() event has been fired already, which means this.channelActive() will
// not be invoked. We have to scheduleAfresh here instead.
scheduleAfresh(ctx);
}
// channelActive() event has not been fired yet. this.channelActive() will be invoked
// and initialization will occur there.
}
@Override
public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
destroy();
}
@Override
public void channelRegistered(ChannelHandlerContext ctx) throws Exception {
// Initialize early if channel is active already.
if (ctx.channel().isActive()) {
scheduleAfresh(ctx);
}
super.channelRegistered(ctx);
}
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
// This method will be invoked only if this handler was added
// before channelActive() event is fired. If a user adds this handler
// after the channelActive() event, scheduleAfresh() will be called by beforeAdd().
scheduleAfresh(ctx);
super.channelActive(ctx);
}
@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
destroy();
super.channelInactive(ctx);
}
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
lastReadTime = System.nanoTime();
ctx.fireChannelRead(msg);
}
@Override
public void write(final ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
if (State.Paused == state) {
// Add the timeout handler when write is complete.
promise.addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) throws Exception {
if (State.Paused == state) {
/*
* Multiple writes can all add a listener, till it is active again (on write success), so it is
* required to only schedule next when the state is actually paused.
*/
scheduleAfresh(ctx);
}
}
});
}
super.write(ctx, msg, promise);
}
@Override
public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
if (evt instanceof PooledConnectionReleaseEvent) {
cancelTimeoutSchedule(ctx);
}
super.userEventTriggered(ctx, evt);
}
private void cancelTimeoutSchedule(ChannelHandlerContext ctx) {
assert ctx.channel().eventLoop().inEventLoop(); /*should only be called from the owner eventloop*/
if (State.Active == state) {
state = State.Paused;
timeout.cancel(false);
}
}
private void scheduleAfresh(ChannelHandlerContext ctx) {
// Avoid the case where destroy() is called before scheduling timeouts.
// See: https://github.com/netty/netty/issues/143
switch (state) {
case Created:
break;
case Active:
return;
case Paused:
break;
case Destroyed:
logger.warn("Not scheduling next read timeout task as the channel handler is removed.");
return;
}
state = State.Active;
lastReadTime = System.nanoTime();
if (timeoutNanos > 0) {
timeout = _scheduleNextTask(ctx, new ReadTimeoutTask(ctx), timeoutNanos);
}
}
private ScheduledFuture<?> _scheduleNextTask(ChannelHandlerContext ctx, ReadTimeoutTask task, long timeoutNanos) {
try {
return ctx.executor().schedule(task, timeoutNanos, TimeUnit.NANOSECONDS);
} catch (Exception e) {
logger.error("Failed to schedule read timeout task. Read timeout will not work on channel: "
+ ctx.channel(), e);
throw e;
}
}
private void destroy() {
state = State.Destroyed;
if (timeout != null) {
timeout.cancel(false);
timeout = null;
}
}
/**
* Is called when a read timeout was detected.
*/
protected void readTimedOut(ChannelHandlerContext ctx) throws Exception {
if (!closed) {
ctx.fireExceptionCaught(ReadTimeoutException.INSTANCE);
ctx.close();
closed = true;
}
}
private final class ReadTimeoutTask implements Runnable {
private final ChannelHandlerContext ctx;
ReadTimeoutTask(ChannelHandlerContext ctx) {
this.ctx = ctx;
}
@Override
public void run() {
if (!ctx.channel().isOpen()) {
return;
}
long currentTime = System.nanoTime();
long nextDelay = timeoutNanos - (currentTime - lastReadTime);
if (nextDelay <= 0) {
// Read timed out - set a new timeout and notify the callback.
timeout = ctx.executor().schedule(this, timeoutNanos, TimeUnit.NANOSECONDS);
try {
readTimedOut(ctx);
} catch (Throwable t) {
ctx.fireExceptionCaught(t);
}
} else {
// Read occurred before the timeout - set a new timeout with shorter delay.
timeout = ctx.executor().schedule(this, nextDelay, TimeUnit.NANOSECONDS);
}
}
}
}