org.eclipse.jetty.server.ShutdownMonitor Maven / Gradle / Ivy
//
// ========================================================================
// Copyright (c) 1995-2016 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 java.io.IOException;
import java.io.InputStreamReader;
import java.io.LineNumberReader;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Properties;
import org.eclipse.jetty.util.StringUtil;
import org.eclipse.jetty.util.thread.ShutdownThread;
/**
* Shutdown/Stop Monitor thread.
*
* This thread listens on the port specified by the STOP.PORT system parameter (defaults to -1 for not listening) for request authenticated with the key given
* by the STOP.KEY system parameter (defaults to "eclipse") for admin requests.
*
* If the stop port is set to zero, then a random port is assigned and the port number is printed to stdout.
*
* Commands "stop" and "status" are currently supported.
*/
public class ShutdownMonitor
{
// Implementation of safe lazy init, using Initialization on Demand Holder technique.
static class Holder
{
static ShutdownMonitor instance = new ShutdownMonitor();
}
public static ShutdownMonitor getInstance()
{
return Holder.instance;
}
/**
* ShutdownMonitorThread
*
* Thread for listening to STOP.PORT for command to stop Jetty.
* If ShowndownMonitor.exitVm is true, then Sytem.exit will also be
* called after the stop.
*
*/
public class ShutdownMonitorThread extends Thread
{
public ShutdownMonitorThread ()
{
setDaemon(true);
setName("ShutdownMonitor");
}
@Override
public void run()
{
if (serverSocket == null)
{
return;
}
while (serverSocket != null)
{
Socket socket = null;
try
{
socket = serverSocket.accept();
LineNumberReader lin = new LineNumberReader(new InputStreamReader(socket.getInputStream()));
String receivedKey = lin.readLine();
if (!key.equals(receivedKey))
{
System.err.println("Ignoring command with incorrect key");
continue;
}
OutputStream out = socket.getOutputStream();
String cmd = lin.readLine();
debug("command=%s",cmd);
if ("stop".equals(cmd))
{
// Graceful Shutdown
debug("Issuing graceful shutdown..");
ShutdownThread.getInstance().run();
// Reply to client
debug("Informing client that we are stopped.");
out.write("Stopped\r\n".getBytes(StringUtil.__UTF8));
out.flush();
// Shutdown Monitor
debug("Shutting down monitor");
close(socket);
socket = null;
close(serverSocket);
serverSocket = null;
if (exitVm)
{
// Kill JVM
debug("Killing JVM");
System.exit(0);
}
}
else if ("status".equals(cmd))
{
// Reply to client
out.write("OK\r\n".getBytes(StringUtil.__UTF8));
out.flush();
}
}
catch (Exception e)
{
debug(e);
System.err.println(e.toString());
}
finally
{
close(socket);
socket = null;
}
}
}
public void start()
{
if (isAlive())
{
System.err.printf("ShutdownMonitorThread already started");
return; // cannot start it again
}
startListenSocket();
if (serverSocket == null)
{
return;
}
if (DEBUG)
System.err.println("Starting ShutdownMonitorThread");
super.start();
}
private void startListenSocket()
{
if (port < 0)
{
if (DEBUG)
System.err.println("ShutdownMonitor not in use (port < 0): " + port);
return;
}
try
{
serverSocket = new ServerSocket(port,1,InetAddress.getByName("127.0.0.1"));
if (port == 0)
{
// server assigned port in use
port = serverSocket.getLocalPort();
System.out.printf("STOP.PORT=%d%n",port);
}
if (key == null)
{
// create random key
key = Long.toString((long)(Long.MAX_VALUE * Math.random() + this.hashCode() + System.currentTimeMillis()),36);
System.out.printf("STOP.KEY=%s%n",key);
}
}
catch (Exception e)
{
debug(e);
System.err.println("Error binding monitor port " + port + ": " + e.toString());
serverSocket = null;
}
finally
{
// establish the port and key that are in use
debug("STOP.PORT=%d",port);
debug("STOP.KEY=%s",key);
debug("%s",serverSocket);
}
}
}
private boolean DEBUG;
private int port;
private String key;
private boolean exitVm;
private ServerSocket serverSocket;
private ShutdownMonitorThread thread;
/**
* Create a ShutdownMonitor using configuration from the System properties.
*
* STOP.PORT = the port to listen on (empty, null, or values less than 0 disable the stop ability)
* STOP.KEY = the magic key/passphrase to allow the stop (defaults to "eclipse")
*
* Note: server socket will only listen on localhost, and a successful stop will issue a System.exit() call.
*/
private ShutdownMonitor()
{
Properties props = System.getProperties();
this.DEBUG = props.containsKey("DEBUG");
// Use values passed thru via /jetty-start/
this.port = Integer.parseInt(props.getProperty("STOP.PORT","-1"));
this.key = props.getProperty("STOP.KEY",null);
this.exitVm = true;
}
private void close(ServerSocket server)
{
if (server == null)
{
return;
}
try
{
server.close();
}
catch (IOException ignore)
{
/* ignore */
}
}
private void close(Socket socket)
{
if (socket == null)
{
return;
}
try
{
socket.close();
}
catch (IOException ignore)
{
/* ignore */
}
}
private void debug(String format, Object... args)
{
if (DEBUG)
{
System.err.printf("[ShutdownMonitor] " + format + "%n",args);
}
}
private void debug(Throwable t)
{
if (DEBUG)
{
t.printStackTrace(System.err);
}
}
public String getKey()
{
return key;
}
public int getPort()
{
return port;
}
public ServerSocket getServerSocket()
{
return serverSocket;
}
public boolean isExitVm()
{
return exitVm;
}
public void setDebug(boolean flag)
{
this.DEBUG = flag;
}
public void setExitVm(boolean exitVm)
{
synchronized (this)
{
if (thread != null && thread.isAlive())
{
throw new IllegalStateException("ShutdownMonitorThread already started");
}
this.exitVm = exitVm;
}
}
public void setKey(String key)
{
synchronized (this)
{
if (thread != null && thread.isAlive())
{
throw new IllegalStateException("ShutdownMonitorThread already started");
}
this.key = key;
}
}
public void setPort(int port)
{
synchronized (this)
{
if (thread != null && thread.isAlive())
{
throw new IllegalStateException("ShutdownMonitorThread already started");
}
this.port = port;
}
}
protected void start() throws Exception
{
ShutdownMonitorThread t = null;
synchronized (this)
{
if (thread != null && thread.isAlive())
{
System.err.printf("ShutdownMonitorThread already started");
return; // cannot start it again
}
thread = new ShutdownMonitorThread();
t = thread;
}
if (t != null)
t.start();
}
protected boolean isAlive ()
{
boolean result = false;
synchronized (this)
{
result = (thread != null && thread.isAlive());
}
return result;
}
@Override
public String toString()
{
return String.format("%s[port=%d]",this.getClass().getName(),port);
}
}