//
// ========================================================================
// Copyright (c) 1995-2017 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// 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 org.eclipse.jetty.io;
import java.io.IOException;
import java.net.InetSocketAddress;
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.concurrent.Executor;
import org.eclipse.jetty.util.component.ContainerLifeCycle;
import org.eclipse.jetty.util.component.Dumpable;
import org.eclipse.jetty.util.log.Log;
import org.eclipse.jetty.util.log.Logger;
import org.eclipse.jetty.util.thread.ExecutionStrategy;
import org.eclipse.jetty.util.thread.Scheduler;
/**
* <p>{@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.</p>
* <p>{@link SelectorManager} subclasses implement methods to return protocol-specific
* {@link EndPoint}s and {@link Connection}s.</p>
*/
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 long _connectTimeout = DEFAULT_CONNECT_TIMEOUT;
private long _selectorIndex;
protected SelectorManager(Executor executor, Scheduler scheduler)
{
this(executor, scheduler, (Runtime.getRuntime().availableProcessors() + 1) / 2);
}
protected SelectorManager(Executor executor, Scheduler scheduler, int selectors)
{
if (selectors <= 0)
throw new IllegalArgumentException("No selectors");
this.executor = executor;
this.scheduler = scheduler;
_selectors = new ManagedSelector[selectors];
}
public Executor getExecutor()
{
return executor;
}
public Scheduler getScheduler()
{
return scheduler;
}
/**
* Get the connect timeout
*
* @return the connect timeout (in milliseconds)
*/
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;
}
/**
* 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
*/
public int getSelectorCount()
{
return _selectors.length;
}
private ManagedSelector chooseSelector(SelectableChannel channel)
{
// Ideally we would like to have all connections from the same client end
// up on the same selector (to try to avoid smearing the data from a single
// client over all cores), but because of proxies, the remote address may not
// really be the client - so we have to hedge our bets to ensure that all
// channels don't end up on the one selector for a proxy.
ManagedSelector candidate1 = null;
if (channel != null)
{
try
{
if (channel instanceof SocketChannel)
{
SocketAddress remote = ((SocketChannel)channel).getRemoteAddress();
if (remote instanceof InetSocketAddress)
{
byte[] addr = ((InetSocketAddress)remote).getAddress().getAddress();
if (addr != null)
{
int s = addr[addr.length - 1] & 0xFF;
candidate1 = _selectors[s % getSelectorCount()];
}
}
}
}
catch (IOException x)
{
LOG.ignore(x);
}
}
// The ++ increment here is not atomic, but it does not matter,
// so long as the value changes sometimes, then connections will
// be distributed over the available selectors.
long s = _selectorIndex++;
int index = (int)(s % getSelectorCount());
ManagedSelector candidate2 = _selectors[index];
if (candidate1 == null || candidate1.size() >= candidate2.size() * 2)
return candidate2;
return candidate1;
}
/**
* <p>Registers a channel to perform a non-blocking connect.</p>
* <p>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).</p>
*
* @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(channel);
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);
}
/**
* <p>Registers a channel to perform non-blocking read/write operations.</p>
* <p>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.</p>
*
* @param channel the channel to register
* @param attachment the attachment object
*/
public void accept(SelectableChannel channel, Object attachment)
{
final ManagedSelector selector = chooseSelector(channel);
selector.submit(selector.new Accept(channel, attachment));
}
/**
* <p>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
*/
public void acceptor(SelectableChannel server)
{
final ManagedSelector selector = chooseSelector(null);
selector.submit(selector.new Acceptor(server));
}
/**
* 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
{
for (int i = 0; i < _selectors.length; i++)
{
ManagedSelector selector = newSelector(i);
_selectors[i] = selector;
addBean(selector);
}
super.doStart();
}
/**
* <p>Factory method for {@link ManagedSelector}.</p>
*
* @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
{
super.doStop();
for (ManagedSelector selector : _selectors)
removeBean(selector);
}
/**
* <p>Callback method invoked when an endpoint is opened.</p>
*
* @param endpoint the endpoint being opened
*/
protected void endPointOpened(EndPoint endpoint)
{
}
/**
* <p>Callback method invoked when an endpoint is closed.</p>
*
* @param endpoint the endpoint being closed
*/
protected void endPointClosed(EndPoint endpoint)
{
}
/**
* <p>Callback method invoked when a connection is opened.</p>
*
* @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;
}
}
/**
* <p>Callback method invoked when a connection is closed.</p>
*
* @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();
}
/**
* <p>Callback method invoked when a non-blocking connect cannot be completed.</p>
* <p>By default it just logs with level warning.</p>
*
* @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();
}
/**
* <p>Factory method to create {@link EndPoint}.</p>
* <p>This method is invoked as a result of the registration of a channel via {@link #connect(SelectableChannel, Object)}
* or {@link #accept(SelectableChannel)}.</p>
*
* @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;
/**
* <p>Factory method to create {@link Connection}.</p>
*
* @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;
}