org.eclipse.jetty.server.LowResourceMonitor Maven / Gradle / Ivy
//
// ========================================================================
// Copyright (c) 1995-2018 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.server;
import org.eclipse.jetty.io.EndPoint;
import org.eclipse.jetty.util.annotation.ManagedAttribute;
import org.eclipse.jetty.util.annotation.ManagedObject;
import org.eclipse.jetty.util.annotation.Name;
import org.eclipse.jetty.util.component.ContainerLifeCycle;
import org.eclipse.jetty.util.log.Log;
import org.eclipse.jetty.util.log.Logger;
import org.eclipse.jetty.util.thread.ScheduledExecutorScheduler;
import org.eclipse.jetty.util.thread.Scheduler;
import org.eclipse.jetty.util.thread.ThreadPool;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;
import java.util.concurrent.Executor;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
/**
*
* A monitor for low resources, low resources can be detected by:
*
* - {@link ThreadPool#isLowOnThreads()} if {@link Connector#getExecutor()} is
* an instance of {@link ThreadPool} and {@link #setMonitorThreads(boolean)} is true.
* - If {@link #setMaxMemory(long)} is non zero then low resources is detected if the JVMs
* {@link Runtime} instance has {@link Runtime#totalMemory()} minus {@link Runtime#freeMemory()}
* greater than {@link #getMaxMemory()}
* - If {@link #setMaxConnections(int)} is non zero then low resources is detected if the total number
* of connections exceeds {@link #getMaxConnections()}. This feature is deprecated and replaced by
* {@link ConnectionLimit}
*
*
*/
@ManagedObject ("Monitor for low resource conditions and activate a low resource mode if detected")
public class LowResourceMonitor extends ContainerLifeCycle
{
private static final Logger LOG = Log.getLogger(LowResourceMonitor.class);
protected final Server _server;
private Scheduler _scheduler;
private Connector[] _monitoredConnectors;
private Set _acceptingConnectors = new HashSet<>();
private int _period=1000;
private int _lowResourcesIdleTimeout=1000;
private int _maxLowResourcesTime=0;
private final AtomicBoolean _low = new AtomicBoolean();
private String _reasons;
private long _lowStarted;
private boolean _acceptingInLowResources = true;
private Set _lowResourceChecks = new HashSet<>();
private final Runnable _monitor = new Runnable()
{
@Override
public void run()
{
if (isRunning())
{
monitor();
_scheduler.schedule( _monitor, _period, TimeUnit.MILLISECONDS);
}
}
};
public LowResourceMonitor(@Name("server") Server server)
{
_server = server;
}
@ManagedAttribute("True if low available threads status is monitored")
public boolean getMonitorThreads()
{
return !getBeans(ConnectorsThreadPoolLowResourceCheck.class).isEmpty();
}
/**
* @param monitorThreads If true, check connectors executors to see if they are
* {@link ThreadPool} instances that are low on threads.
*/
public void setMonitorThreads(boolean monitorThreads)
{
if(monitorThreads)
// already configured?
if ( !getMonitorThreads() ) addLowResourceCheck( new ConnectorsThreadPoolLowResourceCheck() );
else
getBeans(ConnectorsThreadPoolLowResourceCheck.class).forEach(this::removeBean);
}
/**
* @return The maximum connections allowed for the monitored connectors before low resource handling is activated
* @deprecated Replaced by ConnectionLimit
*/
@ManagedAttribute("The maximum connections allowed for the monitored connectors before low resource handling is activated")
@Deprecated
public int getMaxConnections()
{
for(MaxConnectionsLowResourceCheck lowResourceCheck : getBeans(MaxConnectionsLowResourceCheck.class))
{
if (lowResourceCheck.getMaxConnections()>0)
{
return lowResourceCheck.getMaxConnections();
}
}
return -1;
}
/**
* @param maxConnections The maximum connections before low resources state is triggered
* @deprecated Replaced by ConnectionLimit
*/
@Deprecated
public void setMaxConnections(int maxConnections)
{
if (maxConnections>0)
{
if (getBeans(MaxConnectionsLowResourceCheck.class).isEmpty())
{
addLowResourceCheck(new MaxConnectionsLowResourceCheck(maxConnections));
} else
{
getBeans(MaxConnectionsLowResourceCheck.class).forEach( c -> c.setMaxConnections( maxConnections ) );
}
}
else
{
getBeans(ConnectorsThreadPoolLowResourceCheck.class).forEach(this::removeBean);
}
}
@ManagedAttribute("The reasons the monitored connectors are low on resources")
public String getReasons()
{
return _reasons;
}
protected void setReasons(String reasons)
{
_reasons = reasons;
}
@ManagedAttribute("Are the monitored connectors low on resources?")
public boolean isLowOnResources()
{
return _low.get();
}
protected boolean enableLowOnResources(boolean expectedValue, boolean newValue)
{
return _low.compareAndSet(expectedValue, newValue);
}
@ManagedAttribute("The reason(s) the monitored connectors are low on resources")
public String getLowResourcesReasons()
{
return _reasons;
}
protected void setLowResourcesReasons(String reasons)
{
_reasons = reasons;
}
@ManagedAttribute("Get the timestamp in ms since epoch that low resources state started")
public long getLowResourcesStarted()
{
return _lowStarted;
}
public void setLowResourcesStarted(long lowStarted)
{
_lowStarted = lowStarted;
}
@ManagedAttribute("The monitored connectors. If null then all server connectors are monitored")
public Collection getMonitoredConnectors()
{
if (_monitoredConnectors==null)
return Collections.emptyList();
return Arrays.asList( _monitoredConnectors);
}
/**
* @param monitoredConnectors The collections of Connectors that should be monitored for low resources.
*/
public void setMonitoredConnectors(Collection monitoredConnectors)
{
if (monitoredConnectors==null || monitoredConnectors.size()==0)
_monitoredConnectors=null;
else
_monitoredConnectors = monitoredConnectors.toArray(new Connector[monitoredConnectors.size()]);
}
protected Connector[] getMonitoredOrServerConnectors()
{
if (_monitoredConnectors!=null && _monitoredConnectors.length>0)
return _monitoredConnectors;
return _server.getConnectors();
}
@ManagedAttribute("If false, new connections are not accepted while in low resources")
public boolean isAcceptingInLowResources()
{
return _acceptingInLowResources;
}
public void setAcceptingInLowResources(boolean acceptingInLowResources)
{
_acceptingInLowResources = acceptingInLowResources;
}
@ManagedAttribute("The monitor period in ms")
public int getPeriod()
{
return _period;
}
/**
* @param periodMS The period in ms to monitor for low resources
*/
public void setPeriod(int periodMS)
{
_period = periodMS;
}
@ManagedAttribute("The idletimeout in ms to apply to all existing connections when low resources is detected")
public int getLowResourcesIdleTimeout()
{
return _lowResourcesIdleTimeout;
}
/**
* @param lowResourcesIdleTimeoutMS The timeout in ms to apply to EndPoints when in the low resources state.
*/
public void setLowResourcesIdleTimeout(int lowResourcesIdleTimeoutMS)
{
_lowResourcesIdleTimeout = lowResourcesIdleTimeoutMS;
}
@ManagedAttribute("The maximum time in ms that low resources condition can persist before lowResourcesIdleTimeout is applied to new connections as well as existing connections")
public int getMaxLowResourcesTime()
{
return _maxLowResourcesTime;
}
/**
* @param maxLowResourcesTimeMS The time in milliseconds that a low resource state can persist before the low resource idle timeout is reapplied to all connections
*/
public void setMaxLowResourcesTime(int maxLowResourcesTimeMS)
{
_maxLowResourcesTime = maxLowResourcesTimeMS;
}
@ManagedAttribute("The maximum memory (in bytes) that can be used before low resources is triggered. Memory used is calculated as (totalMemory-freeMemory).")
public long getMaxMemory()
{
Collection beans = getBeans(MemoryLowResourceCheck.class);
if(beans.isEmpty())
{
return 0;
}
return beans.stream().findFirst().get().getMaxMemory();
}
/**
* @param maxMemoryBytes The maximum memory in bytes in use before low resources is triggered.
*/
public void setMaxMemory(long maxMemoryBytes)
{
if(maxMemoryBytes<=0)
{
return;
}
Collection beans = getBeans(MemoryLowResourceCheck.class);
if(beans.isEmpty())
addLowResourceCheck( new MemoryLowResourceCheck( maxMemoryBytes ) );
else
beans.forEach( lowResourceCheck -> lowResourceCheck.setMaxMemory( maxMemoryBytes ) );
}
public Set getLowResourceChecks()
{
return _lowResourceChecks;
}
public void setLowResourceChecks( Set lowResourceChecks )
{
updateBeans(_lowResourceChecks.toArray(),lowResourceChecks.toArray());
this._lowResourceChecks = lowResourceChecks;
}
public void addLowResourceCheck( LowResourceCheck lowResourceCheck )
{
addBean(lowResourceCheck);
this._lowResourceChecks.add(lowResourceCheck);
}
protected void monitor()
{
String reasons=null;
for(LowResourceCheck lowResourceCheck : _lowResourceChecks)
{
if(lowResourceCheck.isLowOnResources())
{
reasons = lowResourceCheck.toString();
break;
}
}
if (reasons!=null)
{
// Log the reasons if there is any change in the cause
if (!reasons.equals(getReasons()))
{
LOG.warn("Low Resources: {}",reasons);
setReasons(reasons);
}
// Enter low resources state?
if (enableLowOnResources(false,true))
{
setLowResourcesReasons(reasons);
setLowResourcesStarted(System.currentTimeMillis());
setLowResources();
}
// Too long in low resources state?
if ( getMaxLowResourcesTime()>0 && (System.currentTimeMillis()-getLowResourcesStarted())>getMaxLowResourcesTime())
setLowResources();
}
else
{
if (enableLowOnResources(true,false))
{
LOG.info("Low Resources cleared");
setLowResourcesReasons(null);
setLowResourcesStarted(0);
setReasons(null);
clearLowResources();
}
}
}
@Override
protected void doStart() throws Exception
{
_scheduler = _server.getBean(Scheduler.class);
if (_scheduler==null)
{
_scheduler=new LRMScheduler();
_scheduler.start();
}
super.doStart();
_scheduler.schedule(_monitor,_period,TimeUnit.MILLISECONDS);
}
@Override
protected void doStop() throws Exception
{
if (_scheduler instanceof LRMScheduler )
_scheduler.stop();
super.doStop();
}
protected void setLowResources()
{
for(Connector connector : getMonitoredOrServerConnectors())
{
if (connector instanceof AbstractConnector)
{
AbstractConnector c = (AbstractConnector)connector;
if (!isAcceptingInLowResources() && c.isAccepting())
{
_acceptingConnectors.add(c);
c.setAccepting(false);
}
}
for ( EndPoint endPoint : connector.getConnectedEndPoints())
endPoint.setIdleTimeout(_lowResourcesIdleTimeout);
}
}
protected void clearLowResources()
{
for(Connector connector : getMonitoredOrServerConnectors())
{
for (EndPoint endPoint : connector.getConnectedEndPoints())
endPoint.setIdleTimeout(connector.getIdleTimeout());
}
for (AbstractConnector connector : _acceptingConnectors)
{
connector.setAccepting(true);
}
_acceptingConnectors.clear();
}
protected String low(String reasons, String newReason)
{
if (reasons==null)
return newReason;
return reasons+", "+newReason;
}
private static class LRMScheduler extends ScheduledExecutorScheduler
{
}
interface LowResourceCheck
{
boolean isLowOnResources();
String getReason();
}
//------------------------------------------------------
// default implementations for backward compat
//------------------------------------------------------
public class MainThreadPoolLowResourceCheck implements LowResourceCheck
{
private String reason;
public MainThreadPoolLowResourceCheck()
{
// no op
}
@Override
public boolean isLowOnResources()
{
ThreadPool serverThreads = _server.getThreadPool();
if (serverThreads.isLowOnThreads())
{
reason="Server low on threads: "+serverThreads;
return true;
}
return false;
}
@Override
public String getReason()
{
return reason;
}
@Override
public String toString()
{
return "Check if the server ThreadPool is lowOnThreads";
}
}
public class ConnectorsThreadPoolLowResourceCheck implements LowResourceCheck
{
private String reason;
public ConnectorsThreadPoolLowResourceCheck()
{
// no op
}
@Override
public boolean isLowOnResources()
{
ThreadPool serverThreads = _server.getThreadPool();
if(serverThreads.isLowOnThreads())
{
reason ="Server low on threads: "+serverThreads.getThreads()+", idleThreads:"+serverThreads.getIdleThreads();
return true;
}
for(Connector connector : getMonitoredConnectors())
{
Executor executor = connector.getExecutor();
if (executor instanceof ThreadPool && executor!=serverThreads)
{
ThreadPool connectorThreads=(ThreadPool)executor;
if (connectorThreads.isLowOnThreads())
{
reason ="Connector low on threads: "+connectorThreads;
return true;
}
}
}
return false;
}
@Override
public String getReason()
{
return reason;
}
@Override
public String toString()
{
return "Check if the ThreadPool from monitored connectors are lowOnThreads and if all connections number is higher than the allowed maxConnection";
}
}
@ManagedObject("Check max allowed connections on connectors")
public class MaxConnectionsLowResourceCheck implements LowResourceCheck
{
private String reason;
private int maxConnections;
public MaxConnectionsLowResourceCheck(int maxConnections)
{
this.maxConnections = maxConnections;
}
/**
* @return The maximum connections allowed for the monitored connectors before low resource handling is activated
* @deprecated Replaced by ConnectionLimit
*/
@ManagedAttribute("The maximum connections allowed for the monitored connectors before low resource handling is activated")
@Deprecated
public int getMaxConnections()
{
return maxConnections;
}
/**
* @param maxConnections The maximum connections before low resources state is triggered
* @deprecated Replaced by ConnectionLimit
*/
@Deprecated
public void setMaxConnections(int maxConnections)
{
if (maxConnections>0)
LOG.warn("LowResourceMonitor.setMaxConnections is deprecated. Use ConnectionLimit.");
this.maxConnections = maxConnections;
}
@Override
public boolean isLowOnResources()
{
int connections=0;
for(Connector connector : getMonitoredConnectors())
{
connections+=connector.getConnectedEndPoints().size();
}
if (maxConnections>0 && connections>maxConnections)
{
reason ="Max Connections exceeded: "+connections+">"+maxConnections;
return true;
}
return false;
}
@Override
public String getReason()
{
return reason;
}
@Override
public String toString()
{
return "All connections number is higher than the allowed maxConnection";
}
}
public class MemoryLowResourceCheck implements LowResourceCheck
{
private String reason;
private long maxMemory;
public MemoryLowResourceCheck(long maxMemory)
{
this.maxMemory = maxMemory;
}
@Override
public boolean isLowOnResources()
{
long memory=Runtime.getRuntime().totalMemory()-Runtime.getRuntime().freeMemory();
if (maxMemory>0 && memory>maxMemory)
{
reason = "Max memory exceeded: "+memory+">"+maxMemory;
return true;
}
return false;
}
public long getMaxMemory()
{
return maxMemory;
}
/**
* @param maxMemoryBytes The maximum memory in bytes in use before low resources is triggered.
*/
public void setMaxMemory( long maxMemoryBytes )
{
this.maxMemory = maxMemoryBytes;
}
@Override
public String getReason()
{
return reason;
}
@Override
public String toString()
{
return "Check if used memory is higher than the allowed max memory";
}
}
}