3d6e6136a9
* Decouble EventLoop details from the IO handling for each transport to allow easy re-use of code and customization Motiviation: As today extending EventLoop implementations to add custom logic / metrics / instrumentations is only possible in a very limited way if at all. This is due the fact that most implementations are final or even package-private. That said even if these would be public there are the ability to do something useful with these is very limited as the IO processing and task processing are very tightly coupled. All of the mentioned things are a big pain point in netty 4.x and need improvement. Modifications: This changeset decoubled the IO processing logic from the task processing logic for the main transport (NIO, Epoll, KQueue) by introducing the concept of an IoHandler. The IoHandler itself is responsible to wait for IO readiness and process these IO events. The execution of the IoHandler itself is done by the SingleThreadEventLoop as part of its EventLoop processing. This allows to use the same EventLoopGroup (MultiThreadEventLoupGroup) for all the mentioned transports by just specify a different IoHandlerFactory during construction. Beside this core API change this changeset also allows to easily extend SingleThreadEventExecutor / SingleThreadEventLoop to add custom logic to it which then can be reused by all the transports. The ideas are very similar to what is provided by ScheduledThreadPoolExecutor (that is part of the JDK). This allows for example things like: * Adding instrumentation / metrics: * how many Channels are registered on an SingleThreadEventLoop * how many Channels were handled during the IO processing in an EventLoop run * how many task were handled during the last EventLoop / EventExecutor run * how many outstanding tasks we have ... ... * Implementing custom strategies for choosing the next EventExecutor / EventLoop to use based on these metrics. * Use different Promise / Future / ScheduledFuture implementations * decorate Runnable / Callables when submitted to the EventExecutor / EventLoop As a lot of functionalities are folded into the MultiThreadEventLoopGroup and SingleThreadEventLoopGroup this changeset also removes: * AbstractEventLoop * AbstractEventLoopGroup * EventExecutorChooser * EventExecutorChooserFactory * DefaultEventLoopGroup * DefaultEventExecutor * DefaultEventExecutorGroup Result: Fixes https://github.com/netty/netty/issues/8514 .
180 lines
5.6 KiB
Java
180 lines
5.6 KiB
Java
/*
|
|
* Copyright 2013 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.util.concurrent;
|
|
|
|
import io.netty.util.internal.logging.InternalLogger;
|
|
import io.netty.util.internal.logging.InternalLoggerFactory;
|
|
|
|
import java.util.ArrayDeque;
|
|
import java.util.Queue;
|
|
import java.util.concurrent.Callable;
|
|
import java.util.concurrent.TimeUnit;
|
|
|
|
/**
|
|
* Executes {@link Runnable} objects in the caller's thread. If the {@link #execute(Runnable)} is reentrant it will be
|
|
* queued until the original {@link Runnable} finishes execution.
|
|
* <p>
|
|
* All {@link Throwable} objects thrown from {@link #execute(Runnable)} will be swallowed and logged. This is to ensure
|
|
* that all queued {@link Runnable} objects have the chance to be run.
|
|
*/
|
|
public final class ImmediateEventExecutor extends AbstractEventExecutor {
|
|
private static final InternalLogger logger = InternalLoggerFactory.getInstance(ImmediateEventExecutor.class);
|
|
public static final ImmediateEventExecutor INSTANCE = new ImmediateEventExecutor();
|
|
/**
|
|
* A Runnable will be queued if we are executing a Runnable. This is to prevent a {@link StackOverflowError}.
|
|
*/
|
|
private static final FastThreadLocal<Queue<Runnable>> DELAYED_RUNNABLES = new FastThreadLocal<Queue<Runnable>>() {
|
|
@Override
|
|
protected Queue<Runnable> initialValue() throws Exception {
|
|
return new ArrayDeque<>();
|
|
}
|
|
};
|
|
/**
|
|
* Set to {@code true} if we are executing a runnable.
|
|
*/
|
|
private static final FastThreadLocal<Boolean> RUNNING = new FastThreadLocal<Boolean>() {
|
|
@Override
|
|
protected Boolean initialValue() throws Exception {
|
|
return false;
|
|
}
|
|
};
|
|
|
|
private final Future<?> terminationFuture = new FailedFuture<>(
|
|
GlobalEventExecutor.INSTANCE, new UnsupportedOperationException());
|
|
|
|
private ImmediateEventExecutor() { }
|
|
|
|
@Override
|
|
public boolean inEventLoop(Thread thread) {
|
|
return true;
|
|
}
|
|
|
|
@Override
|
|
public Future<?> shutdownGracefully(long quietPeriod, long timeout, TimeUnit unit) {
|
|
return terminationFuture();
|
|
}
|
|
|
|
@Override
|
|
public Future<?> terminationFuture() {
|
|
return terminationFuture;
|
|
}
|
|
|
|
@Override
|
|
@Deprecated
|
|
public void shutdown() { }
|
|
|
|
@Override
|
|
public boolean isShuttingDown() {
|
|
return false;
|
|
}
|
|
|
|
@Override
|
|
public boolean isShutdown() {
|
|
return false;
|
|
}
|
|
|
|
@Override
|
|
public boolean isTerminated() {
|
|
return false;
|
|
}
|
|
|
|
@Override
|
|
public boolean awaitTermination(long timeout, TimeUnit unit) {
|
|
return false;
|
|
}
|
|
|
|
@Override
|
|
public void execute(Runnable command) {
|
|
if (command == null) {
|
|
throw new NullPointerException("command");
|
|
}
|
|
if (!RUNNING.get()) {
|
|
RUNNING.set(true);
|
|
try {
|
|
command.run();
|
|
} catch (Throwable cause) {
|
|
logger.info("Throwable caught while executing Runnable {}", command, cause);
|
|
} finally {
|
|
Queue<Runnable> delayedRunnables = DELAYED_RUNNABLES.get();
|
|
Runnable runnable;
|
|
while ((runnable = delayedRunnables.poll()) != null) {
|
|
try {
|
|
runnable.run();
|
|
} catch (Throwable cause) {
|
|
logger.info("Throwable caught while executing Runnable {}", runnable, cause);
|
|
}
|
|
}
|
|
RUNNING.set(false);
|
|
}
|
|
} else {
|
|
DELAYED_RUNNABLES.get().add(command);
|
|
}
|
|
}
|
|
|
|
@Override
|
|
public <V> Promise<V> newPromise() {
|
|
return new ImmediatePromise<>(this);
|
|
}
|
|
|
|
@Override
|
|
public <V> ProgressivePromise<V> newProgressivePromise() {
|
|
return new ImmediateProgressivePromise<>(this);
|
|
}
|
|
|
|
@Override
|
|
public ScheduledFuture<?> schedule(Runnable command, long delay,
|
|
TimeUnit unit) {
|
|
throw new UnsupportedOperationException();
|
|
}
|
|
|
|
@Override
|
|
public <V> ScheduledFuture<V> schedule(Callable<V> callable, long delay, TimeUnit unit) {
|
|
throw new UnsupportedOperationException();
|
|
}
|
|
|
|
@Override
|
|
public ScheduledFuture<?> scheduleAtFixedRate(Runnable command, long initialDelay, long period, TimeUnit unit) {
|
|
throw new UnsupportedOperationException();
|
|
}
|
|
|
|
@Override
|
|
public ScheduledFuture<?> scheduleWithFixedDelay(Runnable command, long initialDelay, long delay, TimeUnit unit) {
|
|
throw new UnsupportedOperationException();
|
|
}
|
|
|
|
static class ImmediatePromise<V> extends DefaultPromise<V> {
|
|
ImmediatePromise(EventExecutor executor) {
|
|
super(executor);
|
|
}
|
|
|
|
@Override
|
|
protected void checkDeadLock() {
|
|
// No check
|
|
}
|
|
}
|
|
|
|
static class ImmediateProgressivePromise<V> extends DefaultProgressivePromise<V> {
|
|
ImmediateProgressivePromise(EventExecutor executor) {
|
|
super(executor);
|
|
}
|
|
|
|
@Override
|
|
protected void checkDeadLock() {
|
|
// No check
|
|
}
|
|
}
|
|
}
|