client/monitors/Heartbeat__Monitor.java

//---PACKAGE DECLARATION---
package uk.org.iscream.client.monitors;

//---IMPORTS---
import java.util.HashMap;
import java.util.Iterator;
import uk.org.iscream.client.*;
import uk.org.iscream.core.*;
import uk.org.iscream.util.*;
import uk.org.iscream.componentmanager.*;

/**
 * This Monitor watches heartbeats.
 * It generates an alert when a heartbeat that is expected
 * does not arrive. Unlike all the other monitors, this one
 * is driven by an event *not* occuring, rather than an
 * event occuring. This means it must be actively checking
 * for missing heartbeat's, and thus has an extra inner class
 * thread.
 *
 * @author  $Author: ajm4 $
 * @version $Id: Heartbeat__Monitor.java,v 1.17 2001/03/23 01:08:00 ajm4 Exp $
 */
public class Heartbeat__Monitor extends MonitorSkeleton {

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public final String REVISION = "$Revision: 1.17 $";
    
    /**
     * A description of this monitor
     */
    public final String DESC = "Monitors Heartbeats.";
    
    /**
     * The default (used if not configured) period at
     * which to check for old heartbeats. (in seconds)
     */
    public final int DEFAULT_CHECK_PERIOD = 60;
    
//---STATIC METHODS---

//---CONSTRUCTORS---
    
    /**
     * Constructs a new Heartbeat monitor, and starts off
     * the worker thread.
     */
    public Heartbeat__Monitor() {
        super();
        new HeartbeatWorker().start();
    }

//---PUBLIC METHODS---
    
    /**
     * Analyse a packet of data. In this case, this will just
     * register the fact that a heartbeat has arrived.
     *
     * @param packet The packet of data to analyse
     */
    public void analysePacket(XMLPacket packet) {
        String source = packet.getParam("packet.attributes.machine_name");
        if (!_hosts.containsKey(source)) {
            synchronized(this) {
                _hosts.put(source, new HeartbeatHolder(new Register(source, _name)));
            }
        }
        HeartbeatHolder lastHeartbeat = (HeartbeatHolder) _hosts.get(source);
        lastHeartbeat.setLastHeartbeat(System.currentTimeMillis()/1000);
    }
    
    /**
     * Overrides the {@link java.lang.Object#toString() Object.toString()}
     * method to provide clean logging (every class should have this).
     *
     * This uses the uk.org.iscream.util.NameFormat class
     * to format the toString()
     *
     * @return the name of this class and its CVS revision
     */
    public String toString() {
        return FormatName.getName(
            _name,
            getClass().getName(),
            REVISION);
    }

    /**
     * return the String representation of what the monitor does
     */
    public String getDescription(){
        return DESC;
    }

//---PRIVATE METHODS---
    
    /**
     * Checks whether the time since the last heartbeat
     * is beyond the threshold(s).
     *
     * @param timeSinceLastHB a long time since the last heartbeat arrived
     * @param reg the Register for this host
     * @return the level which has been breached, if any
     */
    private int checkAttributeThreshold(long timeSinceLastHB, Register reg) {
        for(int thresholdLevel = Alert.thresholdLevels.length - 1; thresholdLevel >= 0; thresholdLevel--) {
            if (reg.getThreshold(thresholdLevel) != -1.0) {
                if (((long) reg.getThreshold(thresholdLevel)) < timeSinceLastHB) {
                    return thresholdLevel;
                }
            }
        }
        return Alert.thresholdNORMAL;
    }

//---ACCESSOR/MUTATOR METHODS---
    
    /**
     * Returns a reference to the Queue we're getting data
     * from. This is specific to this monitor.
     *
     * @return a reference to a Queue to get data from
     */
    protected Queue getQueue() {
        return MonitorManager.getInstance().getHeartbeatQueue();
    }
    
//---ATTRIBUTES---

    /**
     * This is the friendly identifier of the
     * component this class is running in.
     * eg, a Filter may be called "filter1",
     * If this class does not have an owning
     * component,  a name from the configuration
     * can be placed here.  This name could also
     * be changed to null for utility classes.
     */
    private String _name = "Heartbeat";
    
    /**
     * A reference to the configuration proxy in use
     */
    private ConfigurationProxy _cp = ConfigurationProxy.getInstance();
    
    /**
     * A HashMap of hosts, with associated HeartbeatHolder's.
     */
    private HashMap _hosts = new HashMap();
    
    /**
     * A reference to the system logger.
     */
    private Logger _logger = ReferenceManager.getInstance().getLogger();

//---STATIC ATTRIBUTES---

//---INNER CLASSES---
    
    /**
     * This inner class simply holding some information
     * about a specific host.
     */
    private class HeartbeatHolder {
        
        /**
         * Construct a new HeartbeatHolder.
         */
        public HeartbeatHolder(Register register) {
            _register = register;
        }
        
        /**
         * Set the time of the last heartbeat
         */
        public void setLastHeartbeat(long lastHeartbeat) {
            _lastHeartbeat = lastHeartbeat;
        }
        
        /**
         * Get the time of the last heartbeat
         */
        public long getLastHeartbeat() {
            return _lastHeartbeat;
        }
        
        /**
         * Get the Register
         */
        public Register getRegister() {
            return _register;
        }
        
        /**
         * last heartbeat time
         */
        private long _lastHeartbeat;
        
        /**
         * register ref
         */
        private Register _register;
    }
    
    /**
     * This worker thread just checks all the hosts and then
     * waits a period of time before doing it again. It sends
     * Alerts as required.
     */
    private class HeartbeatWorker extends Thread {
        
        /**
         * The main run method of this worker thread. It simply
         * checks through all the hosts it has stored, running
         * the analyseHB method on each. It then removes any
         * that have passed a FINAL, and waits a (configured)
         * length of time before doing it again.
         */
        public void run() {
            ConfigurationProxy cp = ConfigurationProxy.getInstance();
            while(true) {
                // this cycle period of this monitor's checks
                int checkPeriod = 0;
                try {
                    checkPeriod = Integer.parseInt(cp.getProperty(_name, "Monitor.Heartbeat.checkPeriod"));
                } catch (PropertyNotFoundException e) {
                    checkPeriod = DEFAULT_CHECK_PERIOD;
                    _logger.write(this.toString(), Logger.WARNING, "Monitor.Heartbeat.checkPeriod value unavailable using default of " + checkPeriod + " seconds");
                } catch (NumberFormatException e) {
                    checkPeriod = DEFAULT_CHECK_PERIOD;
                    _logger.write(this.toString(), Logger.WARNING, "Erronous Monitor.Heartbeat.checkPeriod value in configuration using default of " + checkPeriod + " seconds");
                }
                
                synchronized(this) {
                    // perform the checks (use HB hash, although they *should* be the same)
                    Iterator i = _hosts.keySet().iterator();
                    while(i.hasNext()) {
                        // get host
                        String source = (String) i.next();
                        // check it
                        boolean remove = analyseHB(source);
                        // remove it if it's passed a FINAL
                        if(remove) {
                            i.remove();
                        }
                    }
                }
                
                // wait a while
                try {Thread.sleep(checkPeriod * 1000);} catch (InterruptedException e) {}
            }
        }
        
        /**
         * Analyses a given host's state, and if need be generates
         * a relevant Alert. Note that it also checks if the last
         * alert sent is FINAL, in which case it returns true to
         * indicate removal of this host.
         *
         * @param source the host to check
         * @return whether this host can be deleted
         */
        private boolean analyseHB(String source) {
            ConfigurationProxy cp = ConfigurationProxy.getInstance();
            HeartbeatHolder hbHolder = (HeartbeatHolder) _hosts.get(source);
            Register reg = hbHolder.getRegister();
            
            // get host's HB interval (seconds)
            // this should always exist, thus we set to 0
            int hostHBinterval = 0;
            try {
                hostHBinterval = Integer.parseInt(cp.getProperty("Host."+source, "Host.TCPUpdateTime"));
            } catch (PropertyNotFoundException e) {
                hostHBinterval = 0;
                _logger.write(this.toString(), Logger.WARNING, "TCPUpdateTime value unavailable using default of " + hostHBinterval + " seconds");
            } catch (NumberFormatException e) {
                hostHBinterval = 0;
                _logger.write(this.toString(), Logger.WARNING, "Erronous TCPUpdateTime value in configuration using default of " + hostHBinterval + " seconds");
            }
            
            // get host's last HB time (seconds)
            long lastHeartbeat = hbHolder.getLastHeartbeat();
            // time since last heartbeat (seconds)
            long timeSinceLastHB = (System.currentTimeMillis()/1000) - lastHeartbeat;
            // time since (or until if negative) the expected heartbeat
            long timeSinceExpectedHB = timeSinceLastHB - (long) hostHBinterval;
            
            // best do a check in case the expected heartbeat is in the future
            if(timeSinceExpectedHB < 0) {
                timeSinceExpectedHB = 0;
            }
            
            // find out the threshold level we're at
            int newThreshold = checkAttributeThreshold(timeSinceExpectedHB, reg);
            
            // process the alert
            Heartbeat__Monitor.this.processAlert(newThreshold, "Heartbeat", reg, source, String.valueOf(timeSinceExpectedHB));
            
            if(reg.getLastAlertLevel() == Alert.alertFINAL) {
                return true;
            }
            return false;
        }
    }
}
Revision:	1.18
Committed:	Fri Mar 23 02:32:49 2001 UTC (23 years, 2 months ago) by tdb
Branch:	MAIN
Changes since 1.17:	+103 -17 lines
Log Message:	Fully javadoc'd all the monitors. Also made a few little changes here and there, removing code that had been duplicated by copying other monitors, and tidying up any silly little things (such has hardcoded integer values).
#	User	Rev	Content
1	tdb	1.1	//---PACKAGE DECLARATION---
2	tdb	1.13	package uk.org.iscream.client.monitors;
3	tdb	1.1
4			//---IMPORTS---
5			import java.util.HashMap;
6			import java.util.Iterator;
7	tdb	1.13	import uk.org.iscream.client.*;
8			import uk.org.iscream.core.*;
9			import uk.org.iscream.util.*;
10			import uk.org.iscream.componentmanager.*;
11	tdb	1.1
12			/**
13	tdb	1.18	* This Monitor watches heartbeats.
14			* It generates an alert when a heartbeat that is expected
15			* does not arrive. Unlike all the other monitors, this one
16			* is driven by an event not occuring, rather than an
17			* event occuring. This means it must be actively checking
18			* for missing heartbeat's, and thus has an extra inner class
19			* thread.
20	tdb	1.1	*
21	ajm	1.17	* @author $Author: ajm4 $
22	tdb	1.18	* @version $Id: Heartbeat__Monitor.java,v 1.17 2001/03/23 01:08:00 ajm4 Exp $
23	tdb	1.1	*/
24	ajm	1.14	public class Heartbeat__Monitor extends MonitorSkeleton {
25	tdb	1.1
26			//---FINAL ATTRIBUTES---
27
28			/**
29			* The current CVS revision of this class
30			*/
31	tdb	1.18	public final String REVISION = "$Revision: 1.17 $";
32	tdb	1.1
33	tdb	1.18	/**
34			* A description of this monitor
35			*/
36	tdb	1.1	public final String DESC = "Monitors Heartbeats.";
37
38	tdb	1.18	/**
39			* The default (used if not configured) period at
40			* which to check for old heartbeats. (in seconds)
41			*/
42	tdb	1.3	public final int DEFAULT_CHECK_PERIOD = 60;
43
44	tdb	1.1	//---STATIC METHODS---
45
46			//---CONSTRUCTORS---
47	tdb	1.18
48			/**
49			* Constructs a new Heartbeat monitor, and starts off
50			* the worker thread.
51			*/
52	tdb	1.2	public Heartbeat__Monitor() {
53	ajm	1.16	super();
54	ajm	1.14	new HeartbeatWorker().start();
55	tdb	1.2	}
56
57	tdb	1.1	//---PUBLIC METHODS---
58
59	tdb	1.18	/**
60			* Analyse a packet of data. In this case, this will just
61			* register the fact that a heartbeat has arrived.
62			*
63			* @param packet The packet of data to analyse
64			*/
65	ajm	1.14	public void analysePacket(XMLPacket packet) {
66			String source = packet.getParam("packet.attributes.machine_name");
67			if (!_hosts.containsKey(source)) {
68	tdb	1.9	synchronized(this) {
69	tdb	1.18	_hosts.put(source, new HeartbeatHolder(new Register(source, _name)));
70	tdb	1.1	}
71			}
72	ajm	1.14	HeartbeatHolder lastHeartbeat = (HeartbeatHolder) _hosts.get(source);
73			lastHeartbeat.setLastHeartbeat(System.currentTimeMillis()/1000);
74	tdb	1.1	}
75
76			/**
77			* Overrides the {@link java.lang.Object#toString() Object.toString()}
78			* method to provide clean logging (every class should have this).
79			*
80	tdb	1.13	* This uses the uk.org.iscream.util.NameFormat class
81	tdb	1.1	* to format the toString()
82			*
83			* @return the name of this class and its CVS revision
84			*/
85			public String toString() {
86			return FormatName.getName(
87			_name,
88			getClass().getName(),
89			REVISION);
90			}
91
92			/**
93			* return the String representation of what the monitor does
94			*/
95			public String getDescription(){
96			return DESC;
97			}
98
99			//---PRIVATE METHODS---
100
101	tdb	1.18	/**
102			* Checks whether the time since the last heartbeat
103			* is beyond the threshold(s).
104			*
105			* @param timeSinceLastHB a long time since the last heartbeat arrived
106			* @param reg the Register for this host
107			* @return the level which has been breached, if any
108			*/
109	tdb	1.2	private int checkAttributeThreshold(long timeSinceLastHB, Register reg) {
110	tdb	1.1	for(int thresholdLevel = Alert.thresholdLevels.length - 1; thresholdLevel >= 0; thresholdLevel--) {
111			if (reg.getThreshold(thresholdLevel) != -1.0) {
112	tdb	1.2	if (((long) reg.getThreshold(thresholdLevel)) < timeSinceLastHB) {
113	tdb	1.1	return thresholdLevel;
114			}
115			}
116			}
117	tdb	1.7	return Alert.thresholdNORMAL;
118	tdb	1.1	}
119
120			//---ACCESSOR/MUTATOR METHODS---
121	tdb	1.18
122			/**
123			* Returns a reference to the Queue we're getting data
124			* from. This is specific to this monitor.
125			*
126			* @return a reference to a Queue to get data from
127			*/
128	ajm	1.14	protected Queue getQueue() {
129			return MonitorManager.getInstance().getHeartbeatQueue();
130			}
131
132	tdb	1.1	//---ATTRIBUTES---
133
134			/**
135			* This is the friendly identifier of the
136			* component this class is running in.
137			* eg, a Filter may be called "filter1",
138			* If this class does not have an owning
139			* component, a name from the configuration
140			* can be placed here. This name could also
141			* be changed to null for utility classes.
142			*/
143			private String _name = "Heartbeat";
144
145			/**
146			* A reference to the configuration proxy in use
147			*/
148			private ConfigurationProxy _cp = ConfigurationProxy.getInstance();
149	tdb	1.18
150			/**
151			* A HashMap of hosts, with associated HeartbeatHolder's.
152			*/
153	tdb	1.6	private HashMap _hosts = new HashMap();
154	tdb	1.18
155			/**
156			* A reference to the system logger.
157			*/
158	tdb	1.15	private Logger _logger = ReferenceManager.getInstance().getLogger();
159	tdb	1.1
160			//---STATIC ATTRIBUTES---
161
162			//---INNER CLASSES---
163	tdb	1.18
164			/**
165			* This inner class simply holding some information
166			* about a specific host.
167			*/
168	tdb	1.1	private class HeartbeatHolder {
169
170	tdb	1.18	/**
171			* Construct a new HeartbeatHolder.
172			*/
173			public HeartbeatHolder(Register register) {
174			_register = register;
175	tdb	1.6	}
176
177	tdb	1.18	/**
178			* Set the time of the last heartbeat
179			*/
180	tdb	1.2	public void setLastHeartbeat(long lastHeartbeat) {
181	tdb	1.1	_lastHeartbeat = lastHeartbeat;
182			}
183
184	tdb	1.18	/**
185			* Get the time of the last heartbeat
186			*/
187	tdb	1.2	public long getLastHeartbeat() {
188	tdb	1.1	return _lastHeartbeat;
189			}
190
191	tdb	1.18	/**
192			* Get the Register
193			*/
194			public Register getRegister() {
195			return _register;
196	tdb	1.6	}
197
198	tdb	1.18	/**
199			* last heartbeat time
200			*/
201	tdb	1.2	private long _lastHeartbeat;
202	tdb	1.18
203			/**
204			* register ref
205			*/
206			private Register _register;
207	ajm	1.14	}
208
209	tdb	1.18	/**
210			* This worker thread just checks all the hosts and then
211			* waits a period of time before doing it again. It sends
212			* Alerts as required.
213			*/
214	ajm	1.14	private class HeartbeatWorker extends Thread {
215
216	tdb	1.18	/**
217			* The main run method of this worker thread. It simply
218			* checks through all the hosts it has stored, running
219			* the analyseHB method on each. It then removes any
220			* that have passed a FINAL, and waits a (configured)
221			* length of time before doing it again.
222			*/
223	ajm	1.14	public void run() {
224			ConfigurationProxy cp = ConfigurationProxy.getInstance();
225			while(true) {
226			// this cycle period of this monitor's checks
227			int checkPeriod = 0;
228			try {
229			checkPeriod = Integer.parseInt(cp.getProperty(_name, "Monitor.Heartbeat.checkPeriod"));
230			} catch (PropertyNotFoundException e) {
231			checkPeriod = DEFAULT_CHECK_PERIOD;
232			_logger.write(this.toString(), Logger.WARNING, "Monitor.Heartbeat.checkPeriod value unavailable using default of " + checkPeriod + " seconds");
233			} catch (NumberFormatException e) {
234			checkPeriod = DEFAULT_CHECK_PERIOD;
235			_logger.write(this.toString(), Logger.WARNING, "Erronous Monitor.Heartbeat.checkPeriod value in configuration using default of " + checkPeriod + " seconds");
236			}
237
238			synchronized(this) {
239			// perform the checks (use HB hash, although they should be the same)
240			Iterator i = _hosts.keySet().iterator();
241			while(i.hasNext()) {
242			// get host
243			String source = (String) i.next();
244			// check it
245			boolean remove = analyseHB(source);
246	tdb	1.18	// remove it if it's passed a FINAL
247	ajm	1.14	if(remove) {
248			i.remove();
249			}
250			}
251			}
252
253			// wait a while
254			try {Thread.sleep(checkPeriod * 1000);} catch (InterruptedException e) {}
255			}
256			}
257	ajm	1.16
258	tdb	1.18	/**
259			* Analyses a given host's state, and if need be generates
260			* a relevant Alert. Note that it also checks if the last
261			* alert sent is FINAL, in which case it returns true to
262			* indicate removal of this host.
263			*
264			* @param source the host to check
265			* @return whether this host can be deleted
266			*/
267	ajm	1.16	private boolean analyseHB(String source) {
268			ConfigurationProxy cp = ConfigurationProxy.getInstance();
269			HeartbeatHolder hbHolder = (HeartbeatHolder) _hosts.get(source);
270	tdb	1.18	Register reg = hbHolder.getRegister();
271	ajm	1.16
272			// get host's HB interval (seconds)
273			// this should always exist, thus we set to 0
274			int hostHBinterval = 0;
275			try {
276			hostHBinterval = Integer.parseInt(cp.getProperty("Host."+source, "Host.TCPUpdateTime"));
277			} catch (PropertyNotFoundException e) {
278			hostHBinterval = 0;
279			_logger.write(this.toString(), Logger.WARNING, "TCPUpdateTime value unavailable using default of " + hostHBinterval + " seconds");
280			} catch (NumberFormatException e) {
281			hostHBinterval = 0;
282			_logger.write(this.toString(), Logger.WARNING, "Erronous TCPUpdateTime value in configuration using default of " + hostHBinterval + " seconds");
283			}
284
285			// get host's last HB time (seconds)
286			long lastHeartbeat = hbHolder.getLastHeartbeat();
287			// time since last heartbeat (seconds)
288			long timeSinceLastHB = (System.currentTimeMillis()/1000) - lastHeartbeat;
289			// time since (or until if negative) the expected heartbeat
290			long timeSinceExpectedHB = timeSinceLastHB - (long) hostHBinterval;
291
292			// best do a check in case the expected heartbeat is in the future
293			if(timeSinceExpectedHB < 0) {
294			timeSinceExpectedHB = 0;
295			}
296
297			// find out the threshold level we're at
298			int newThreshold = checkAttributeThreshold(timeSinceExpectedHB, reg);
299
300			// process the alert
301	ajm	1.17	Heartbeat__Monitor.this.processAlert(newThreshold, "Heartbeat", reg, source, String.valueOf(timeSinceExpectedHB));
302	ajm	1.16
303			if(reg.getLastAlertLevel() == Alert.alertFINAL) {
304			return true;
305			}
306			return false;
307			}
308	ajm	1.14	}
309	tdb	1.1	}