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The core jetty server artifact.
//
// ========================================================================
// Copyright (c) 1995 Mort Bay Consulting Pty Ltd and others.
//
// This program and the accompanying materials are made available under the
// terms of the Eclipse Public License v. 2.0 which is available at
// https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
// which is available at https://www.apache.org/licenses/LICENSE-2.0.
//
// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
// ========================================================================
//
package org.eclipse.jetty.server.session;
import java.util.concurrent.TimeUnit;
import org.eclipse.jetty.server.SessionIdManager;
import org.eclipse.jetty.util.annotation.ManagedAttribute;
import org.eclipse.jetty.util.annotation.ManagedObject;
import org.eclipse.jetty.util.component.AbstractLifeCycle;
import org.eclipse.jetty.util.thread.AutoLock;
import org.eclipse.jetty.util.thread.ScheduledExecutorScheduler;
import org.eclipse.jetty.util.thread.Scheduler;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* HouseKeeper
*
* There is 1 session HouseKeeper per SessionIdManager instance.
*/
@ManagedObject
public class HouseKeeper extends AbstractLifeCycle
{
private static final Logger LOG = LoggerFactory.getLogger(HouseKeeper.class);
public static final long DEFAULT_PERIOD_MS = 1000L * 60 * 10;
private final AutoLock _lock = new AutoLock();
protected SessionIdManager _sessionIdManager;
protected Scheduler _scheduler;
protected Scheduler.Task _task; //scavenge task
protected Runner _runner;
protected boolean _ownScheduler = false;
private long _intervalMs = DEFAULT_PERIOD_MS;
/**
* Runner
*/
protected class Runner implements Runnable
{
@Override
public void run()
{
try
{
scavenge();
}
finally
{
try (AutoLock l = _lock.lock())
{
if (_scheduler != null && _scheduler.isRunning())
_task = _scheduler.schedule(this, _intervalMs, TimeUnit.MILLISECONDS);
}
}
}
}
/**
* SessionIdManager associated with this scavenger
*
* @param sessionIdManager the session id manager
*/
public void setSessionIdManager(SessionIdManager sessionIdManager)
{
if (isStarted())
throw new IllegalStateException("HouseKeeper started");
_sessionIdManager = sessionIdManager;
}
@Override
protected void doStart() throws Exception
{
if (_sessionIdManager == null)
throw new IllegalStateException("No SessionIdManager for Housekeeper");
setIntervalSec(getIntervalSec());
super.doStart();
}
/**
* If scavenging is not scheduled, schedule it.
*
* @throws Exception if any error during scheduling the scavenging
*/
protected void startScavenging() throws Exception
{
try (AutoLock l = _lock.lock())
{
if (_scheduler == null)
{
if (_sessionIdManager instanceof DefaultSessionIdManager)
{
//try and use a common scheduler, fallback to own
_scheduler = ((DefaultSessionIdManager)_sessionIdManager).getServer().getBean(Scheduler.class);
}
if (_scheduler == null)
{
_scheduler = new ScheduledExecutorScheduler(String.format("Session-HouseKeeper-%x", hashCode()), false);
_ownScheduler = true;
_scheduler.start();
if (LOG.isDebugEnabled())
LOG.debug("{} using own scheduler for scavenging", _sessionIdManager.getWorkerName());
}
else if (!_scheduler.isStarted())
throw new IllegalStateException("Shared scheduler not started");
}
//cancel any previous task
if (_task != null)
_task.cancel();
if (_runner == null)
_runner = new Runner();
if (LOG.isDebugEnabled())
LOG.debug("{} scavenging every {}ms", _sessionIdManager.getWorkerName(), _intervalMs);
_task = _scheduler.schedule(_runner, _intervalMs, TimeUnit.MILLISECONDS);
}
}
/**
* If scavenging is scheduled, stop it.
*
* @throws Exception if any error during stopping the scavenging
*/
protected void stopScavenging() throws Exception
{
try (AutoLock l = _lock.lock())
{
if (_task != null)
{
_task.cancel();
if (LOG.isDebugEnabled())
LOG.debug("{} stopped scavenging", _sessionIdManager.getWorkerName());
}
_task = null;
if (_ownScheduler && _scheduler != null)
{
_ownScheduler = false;
_scheduler.stop();
_scheduler = null;
}
_runner = null;
}
}
@Override
protected void doStop() throws Exception
{
try (AutoLock l = _lock.lock())
{
stopScavenging();
_scheduler = null;
}
super.doStop();
}
/**
* Set the period between scavenge cycles
*
* @param sec the interval (in seconds)
* @throws Exception if any error during restarting the scavenging
*/
public void setIntervalSec(long sec) throws Exception
{
try (AutoLock l = _lock.lock())
{
if (isStarted() || isStarting())
{
if (sec <= 0)
{
_intervalMs = 0L;
if (LOG.isDebugEnabled())
LOG.debug("{} scavenging disabled", _sessionIdManager.getWorkerName());
stopScavenging();
}
else
{
if (sec < 10)
LOG.warn("{} short interval of {}sec for session scavenging.", _sessionIdManager.getWorkerName(), sec);
_intervalMs = sec * 1000L;
//add a bit of variability into the scavenge time so that not all
//nodes with the same scavenge interval sync up
long tenPercent = _intervalMs / 10;
if ((System.currentTimeMillis() % 2) == 0)
_intervalMs += tenPercent;
if (isStarting() || isStarted())
{
startScavenging();
}
}
}
else
{
_intervalMs = sec * 1000L;
}
}
}
/**
* Get the period between scavenge cycles.
*
* @return the interval (in seconds)
*/
@ManagedAttribute(value = "secs between scavenge cycles", readonly = true)
public long getIntervalSec()
{
try (AutoLock l = _lock.lock())
{
return _intervalMs / 1000;
}
}
/**
* Periodically do session housekeeping
*/
public void scavenge()
{
//don't attempt to scavenge if we are shutting down
if (isStopping() || isStopped())
return;
if (LOG.isDebugEnabled())
LOG.debug("{} scavenging sessions", _sessionIdManager.getWorkerName());
//find the session managers
for (SessionHandler manager : _sessionIdManager.getSessionHandlers())
{
if (manager != null)
{
try
{
manager.scavenge();
}
catch (Exception e)
{
LOG.warn("Unable to scavenge", e);
}
}
}
}
@Override
public String toString()
{
try (AutoLock l = _lock.lock())
{
return super.toString() + "[interval=" + _intervalMs + ", ownscheduler=" + _ownScheduler + "]";
}
}
}