com.signalfx.shaded.jetty.io.SelectorManager Maven / Gradle / Ivy
//
// ========================================================================
// Copyright (c) 1995-2022 Mort Bay Consulting Pty Ltd and others.
// ------------------------------------------------------------------------
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
//
// The Eclipse Public License is available at
// http://www.eclipse.org/legal/epl-v10.html
//
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
//
// You may elect to redistribute this code under either of these licenses.
// ========================================================================
//
package com.signalfx.shaded.jetty.io;
import java.io.Closeable;
import java.io.IOException;
import java.net.Socket;
import java.net.SocketAddress;
import java.nio.channels.SelectableChannel;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.EventListener;
import java.util.List;
import java.util.concurrent.Executor;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.function.IntUnaryOperator;
import com.signalfx.shaded.jetty.util.ProcessorUtils;
import com.signalfx.shaded.jetty.util.annotation.ManagedAttribute;
import com.signalfx.shaded.jetty.util.annotation.ManagedObject;
import com.signalfx.shaded.jetty.util.component.ContainerLifeCycle;
import com.signalfx.shaded.jetty.util.component.Dumpable;
import com.signalfx.shaded.jetty.util.log.Log;
import com.signalfx.shaded.jetty.util.log.Logger;
import com.signalfx.shaded.jetty.util.thread.Scheduler;
import com.signalfx.shaded.jetty.util.thread.ThreadPool;
import com.signalfx.shaded.jetty.util.thread.ThreadPoolBudget;
/**
* {@link SelectorManager} manages a number of {@link ManagedSelector}s that
* simplify the non-blocking primitives provided by the JVM via the {@code java.nio} package.
* {@link SelectorManager} subclasses implement methods to return protocol-specific
* {@link EndPoint}s and {@link Connection}s.
*/
@ManagedObject("Manager of the NIO Selectors")
public abstract class SelectorManager extends ContainerLifeCycle implements Dumpable
{
public static final int DEFAULT_CONNECT_TIMEOUT = 15000;
protected static final Logger LOG = Log.getLogger(SelectorManager.class);
private final Executor executor;
private final Scheduler scheduler;
private final ManagedSelector[] _selectors;
private final AtomicInteger _selectorIndex = new AtomicInteger();
private final IntUnaryOperator _selectorIndexUpdate;
private final List _acceptListeners = new ArrayList<>();
private long _connectTimeout = DEFAULT_CONNECT_TIMEOUT;
private ThreadPoolBudget.Lease _lease;
private static int defaultSelectors(Executor executor)
{
if (executor instanceof ThreadPool.SizedThreadPool)
{
int threads = ((ThreadPool.SizedThreadPool)executor).getMaxThreads();
int cpus = ProcessorUtils.availableProcessors();
return Math.max(1, Math.min(cpus / 2, threads / 16));
}
return Math.max(1, ProcessorUtils.availableProcessors() / 2);
}
protected SelectorManager(Executor executor, Scheduler scheduler)
{
this(executor, scheduler, -1);
}
/**
* @param executor The executor to use for handling selected {@link EndPoint}s
* @param scheduler The scheduler to use for timing events
* @param selectors The number of selectors to use, or -1 for a default derived
* from a heuristic over available CPUs and thread pool size.
*/
protected SelectorManager(Executor executor, Scheduler scheduler, int selectors)
{
if (selectors <= 0)
selectors = defaultSelectors(executor);
this.executor = executor;
this.scheduler = scheduler;
_selectors = new ManagedSelector[selectors];
_selectorIndexUpdate = index -> (index + 1) % _selectors.length;
}
@ManagedAttribute("The Executor")
public Executor getExecutor()
{
return executor;
}
@ManagedAttribute("The Scheduler")
public Scheduler getScheduler()
{
return scheduler;
}
/**
* Get the connect timeout
*
* @return the connect timeout (in milliseconds)
*/
@ManagedAttribute("The Connection timeout (ms)")
public long getConnectTimeout()
{
return _connectTimeout;
}
/**
* Set the connect timeout (in milliseconds)
*
* @param milliseconds the number of milliseconds for the timeout
*/
public void setConnectTimeout(long milliseconds)
{
_connectTimeout = milliseconds;
}
/**
* @return -1
* @deprecated
*/
@Deprecated
public int getReservedThreads()
{
return -1;
}
/**
* @param threads ignored
* @deprecated
*/
@Deprecated
public void setReservedThreads(int threads)
{
throw new UnsupportedOperationException();
}
/**
* Executes the given task in a different thread.
*
* @param task the task to execute
*/
protected void execute(Runnable task)
{
executor.execute(task);
}
/**
* @return the number of selectors in use
*/
@ManagedAttribute("The number of NIO Selectors")
public int getSelectorCount()
{
return _selectors.length;
}
private ManagedSelector chooseSelector()
{
return _selectors[_selectorIndex.updateAndGet(_selectorIndexUpdate)];
}
/**
* Registers a channel to perform a non-blocking connect.
* The channel must be set in non-blocking mode, {@link SocketChannel#connect(SocketAddress)}
* must be called prior to calling this method, and the connect operation must not be completed
* (the return value of {@link SocketChannel#connect(SocketAddress)} must be false).
*
* @param channel the channel to register
* @param attachment the attachment object
* @see #accept(SelectableChannel, Object)
*/
public void connect(SelectableChannel channel, Object attachment)
{
ManagedSelector set = chooseSelector();
set.submit(set.new Connect(channel, attachment));
}
/**
* @param channel the channel to accept
* @see #accept(SelectableChannel, Object)
*/
public void accept(SelectableChannel channel)
{
accept(channel, null);
}
/**
* Registers a channel to perform non-blocking read/write operations.
* This method is called just after a channel has been accepted by {@link ServerSocketChannel#accept()},
* or just after having performed a blocking connect via {@link Socket#connect(SocketAddress, int)}, or
* just after a non-blocking connect via {@link SocketChannel#connect(SocketAddress)} that completed
* successfully.
*
* @param channel the channel to register
* @param attachment the attachment object
*/
public void accept(SelectableChannel channel, Object attachment)
{
ManagedSelector selector = chooseSelector();
selector.submit(selector.new Accept(channel, attachment));
}
/**
* Registers a server channel for accept operations.
* When a {@link SocketChannel} is accepted from the given {@link ServerSocketChannel}
* then the {@link #accepted(SelectableChannel)} method is called, which must be
* overridden by a derivation of this class to handle the accepted channel
*
* @param server the server channel to register
* @return A Closable that allows the acceptor to be cancelled
*/
public Closeable acceptor(SelectableChannel server)
{
ManagedSelector selector = chooseSelector();
ManagedSelector.Acceptor acceptor = selector.new Acceptor(server);
selector.submit(acceptor);
return acceptor;
}
/**
* Callback method when a channel is accepted from the {@link ServerSocketChannel}
* passed to {@link #acceptor(SelectableChannel)}.
* The default impl throws an {@link UnsupportedOperationException}, so it must
* be overridden by subclasses if a server channel is provided.
*
* @param channel the
* @throws IOException if unable to accept channel
*/
protected void accepted(SelectableChannel channel) throws IOException
{
throw new UnsupportedOperationException();
}
@Override
protected void doStart() throws Exception
{
_lease = ThreadPoolBudget.leaseFrom(getExecutor(), this, _selectors.length);
for (int i = 0; i < _selectors.length; i++)
{
ManagedSelector selector = newSelector(i);
_selectors[i] = selector;
addBean(selector);
}
super.doStart();
}
/**
*
Factory method for {@link ManagedSelector}.
*
* @param id an identifier for the {@link ManagedSelector to create}
* @return a new {@link ManagedSelector}
*/
protected ManagedSelector newSelector(int id)
{
return new ManagedSelector(this, id);
}
@Override
protected void doStop() throws Exception
{
try
{
super.doStop();
}
finally
{
// Cleanup
for (ManagedSelector selector : _selectors)
{
if (selector != null)
removeBean(selector);
}
Arrays.fill(_selectors, null);
if (_lease != null)
_lease.close();
}
}
/**
* Callback method invoked when an endpoint is opened.
*
* @param endpoint the endpoint being opened
*/
protected void endPointOpened(EndPoint endpoint)
{
}
/**
* Callback method invoked when an endpoint is closed.
*
* @param endpoint the endpoint being closed
*/
protected void endPointClosed(EndPoint endpoint)
{
}
/**
* Callback method invoked when a connection is opened.
*
* @param connection the connection just opened
*/
public void connectionOpened(Connection connection)
{
try
{
connection.onOpen();
}
catch (Throwable x)
{
if (isRunning())
LOG.warn("Exception while notifying connection " + connection, x);
else
LOG.debug("Exception while notifying connection " + connection, x);
throw x;
}
}
/**
* Callback method invoked when a connection is closed.
*
* @param connection the connection just closed
*/
public void connectionClosed(Connection connection)
{
try
{
connection.onClose();
}
catch (Throwable x)
{
LOG.debug("Exception while notifying connection " + connection, x);
}
}
protected boolean doFinishConnect(SelectableChannel channel) throws IOException
{
return ((SocketChannel)channel).finishConnect();
}
protected boolean isConnectionPending(SelectableChannel channel)
{
return ((SocketChannel)channel).isConnectionPending();
}
protected SelectableChannel doAccept(SelectableChannel server) throws IOException
{
return ((ServerSocketChannel)server).accept();
}
/**
* Callback method invoked when a non-blocking connect cannot be completed.
* By default it just logs with level warning.
*
* @param channel the channel that attempted the connect
* @param ex the exception that caused the connect to fail
* @param attachment the attachment object associated at registration
*/
protected void connectionFailed(SelectableChannel channel, Throwable ex, Object attachment)
{
LOG.warn(String.format("%s - %s", channel, attachment), ex);
}
protected Selector newSelector() throws IOException
{
return Selector.open();
}
/**
* Factory method to create {@link EndPoint}.
* This method is invoked as a result of the registration of a channel via {@link #connect(SelectableChannel, Object)}
* or {@link #accept(SelectableChannel)}.
*
* @param channel the channel associated to the endpoint
* @param selector the selector the channel is registered to
* @param selectionKey the selection key
* @return a new endpoint
* @throws IOException if the endPoint cannot be created
* @see #newConnection(SelectableChannel, EndPoint, Object)
*/
protected abstract EndPoint newEndPoint(SelectableChannel channel, ManagedSelector selector, SelectionKey selectionKey) throws IOException;
/**
* Factory method to create {@link Connection}.
*
* @param channel the channel associated to the connection
* @param endpoint the endpoint
* @param attachment the attachment
* @return a new connection
* @throws IOException if unable to create new connection
*/
public abstract Connection newConnection(SelectableChannel channel, EndPoint endpoint, Object attachment) throws IOException;
public void addEventListener(EventListener listener)
{
if (isRunning())
throw new IllegalStateException(this.toString());
if (listener instanceof AcceptListener)
addAcceptListener((AcceptListener)listener);
}
public void removeEventListener(EventListener listener)
{
if (isRunning())
throw new IllegalStateException(this.toString());
if (listener instanceof AcceptListener)
removeAcceptListener((AcceptListener)listener);
}
public void addAcceptListener(AcceptListener listener)
{
if (!_acceptListeners.contains(listener))
_acceptListeners.add(listener);
}
public void removeAcceptListener(AcceptListener listener)
{
_acceptListeners.remove(listener);
}
protected void onAccepting(SelectableChannel channel)
{
for (AcceptListener l : _acceptListeners)
{
try
{
l.onAccepting(channel);
}
catch (Throwable x)
{
LOG.warn(x);
}
}
}
protected void onAcceptFailed(SelectableChannel channel, Throwable cause)
{
for (AcceptListener l : _acceptListeners)
{
try
{
l.onAcceptFailed(channel, cause);
}
catch (Throwable x)
{
LOG.warn(x);
}
}
}
protected void onAccepted(SelectableChannel channel)
{
for (AcceptListener l : _acceptListeners)
{
try
{
l.onAccepted(channel);
}
catch (Throwable x)
{
LOG.warn(x);
}
}
}
/**
* A listener for accept events.
* This listener is called from either the selector or acceptor thread
* and implementations must be non blocking and fast.
*/
public interface AcceptListener extends EventListener
{
/**
* Called immediately after a new SelectableChannel is accepted, but
* before it has been submitted to the {@link SelectorManager}.
*
* @param channel the accepted channel
*/
default void onAccepting(SelectableChannel channel)
{
}
/**
* Called if the processing of the accepted channel fails prior to calling
* {@link #onAccepted(SelectableChannel)}.
*
* @param channel the accepted channel
* @param cause the cause of the failure
*/
default void onAcceptFailed(SelectableChannel channel, Throwable cause)
{
}
/**
* Called after the accepted channel has been allocated an {@link EndPoint}
* and associated {@link Connection}, and after the onOpen notifications have
* been called on both endPoint and connection.
*
* @param channel the accepted channel
*/
default void onAccepted(SelectableChannel channel)
{
}
}
}