[lttng-dev] [PATCH lttng-ust] JUL: use root logger to capture events

Tan Dung Le Tran tan.dung.le.tran at ericsson.com
Thu Jun 26 12:05:31 EDT 2014


Hi David,

Is this patch applicable for lttng-ust "origin/stable-2.4" ?

Thanks,
Tan


-----Original Message-----
From: David Goulet [mailto:dgoulet at efficios.com] 
Sent: June-16-14 11:31 AM
To: lttng-dev at lists.lttng.org
Subject: [lttng-dev] [PATCH lttng-ust] JUL: use root logger to capture events

The JUL agent now uses the root logger ("") to capture all events. This allows us to remove the Timer thread and cleanup a huge portion of the code base. It simplifies a great deal the internal structure of the agent since we don't have to monitor the Logger object anymore.

Since tracepoint filtering is done in UST, we just the LTTng handler to the root logger and send everything to UST except disabled events.

Signed-off-by: David Goulet <dgoulet at efficios.com>
---
 .../org/lttng/ust/jul/LTTngLogHandler.java         | 100 ++------------
 .../org/lttng/ust/jul/LTTngSessiondCmd2_4.java     | 145 ++++-----------------
 .../org/lttng/ust/jul/LTTngTCPSessiondClient.java  | 105 +--------------
 3 files changed, 41 insertions(+), 309 deletions(-)

diff --git a/liblttng-ust-jul/org/lttng/ust/jul/LTTngLogHandler.java b/liblttng-ust-jul/org/lttng/ust/jul/LTTngLogHandler.java
index 8c79512..00e8e3c 100644
--- a/liblttng-ust-jul/org/lttng/ust/jul/LTTngLogHandler.java
+++ b/liblttng-ust-jul/org/lttng/ust/jul/LTTngLogHandler.java
@@ -29,40 +29,16 @@ import java.util.Map;
 
 import org.lttng.ust.jul.LTTngUst;
 
-class LTTngLogger {
-	/*
-	 * The log handler is attached to the logger when the reference count is
-	 * nonzero. Each event referring to a logger holds a reference to that
-	 * logger. If down to 0, this object is removed from the handler.
-	 */
-	public int refcount;
-	public String name;
-	Logger logger;
-
-	public LTTngLogger(String name, Logger logger) {
-		this.name = name;
-		this.refcount = 0;
-		this.logger = logger;
-	}
-
-	public void attach(LTTngLogHandler handler) {
-		this.logger.addHandler(handler);
-	}
-
-	public void detach(LTTngLogHandler handler) {
-		this.logger.removeHandler(handler);
-	}
-}
-
 public class LTTngLogHandler extends Handler {
 	/* Am I a root Log Handler. */
 	public int is_root = 0;
+	public int attached = 0;
 
 	public LogManager logManager;
 
 	/* Logger object attached to this handler that can trigger a tracepoint. */
-	private Map<String, LTTngLogger> loggerMap =
-		Collections.synchronizedMap(new HashMap<String, LTTngLogger>());
+	public Map<String, LTTngEvent> disabledEvents =
+		Collections.synchronizedMap(new HashMap<String, LTTngEvent>());
 
 	/* Constructor */
 	public LTTngLogHandler(LogManager logManager) { @@ -75,68 +51,10 @@ public class LTTngLogHandler extends Handler {
 	}
 
 	/*
-	 * Return true if the logger is enabled and attached. Else, if not found,
-	 * return false.
-	 */
-	public boolean exists(String name) {
-		if (loggerMap.get(name) != null) {
-			return true;
-		} else {
-			return false;
-		}
-	}
-
-	/*
-	 * Attach an event to this handler. If no logger object exists, one is
-	 * created else the refcount is incremented.
-	 */
-	public void attachEvent(LTTngEvent event) {
-		Logger logger;
-		LTTngLogger lttngLogger;
-
-		/* Does the logger actually exist. */
-		logger = this.logManager.getLogger(event.name);
-		if (logger == null) {
-			/* Stop attach right now. */
-			return;
-		}
-
-		lttngLogger = loggerMap.get(event.name);
-		if (lttngLogger == null) {
-			lttngLogger = new LTTngLogger(event.name, logger);
-
-			/* Attach the handler to the logger and add is to the map. */
-			lttngLogger.attach(this);
-			lttngLogger.refcount = 1;
-			loggerMap.put(lttngLogger.name, lttngLogger);
-		} else {
-			lttngLogger.refcount += 1;
-		}
-	}
-
-	/*
-	 * Dettach an event from this handler. If the refcount goes down to 0, the
-	 * logger object is removed thus not attached anymore.
-	 */
-	public void detachEvent(LTTngEvent event) {
-		LTTngLogger logger;
-
-		logger = loggerMap.get(event.name);
-		if (logger != null) {
-			logger.refcount -= 1;
-			if (logger.refcount == 0) {
-				/* Dettach from handler since no more event is associated. */
-				logger.detach(this);
-				loggerMap.remove(logger);
-			}
-		}
-	}
-
-	/*
 	 * Cleanup this handler state meaning put it back to a vanilla state.
 	 */
 	public void clear() {
-		this.loggerMap.clear();
+		this.disabledEvents.clear();
 	}
 
 	@Override
@@ -147,10 +65,14 @@ public class LTTngLogHandler extends Handler {
 
 	@Override
 	public void publish(LogRecord record) {
-		LTTngLogger logger;
+		LTTngEvent event;
 
-		logger = loggerMap.get(record.getLoggerName());
-		if (logger == null) {
+		/*
+		 * Check if the logger has been disabled and if yes don't fire the
+		 * tracepoint.
+		 */
+		event = this.disabledEvents.get(record.getLoggerName());
+		if (event != null) {
 			/* Ignore and don't fire TP. */
 			return;
 		}
diff --git a/liblttng-ust-jul/org/lttng/ust/jul/LTTngSessiondCmd2_4.java b/liblttng-ust-jul/org/lttng/ust/jul/LTTngSessiondCmd2_4.java
index 6808326..dc068f1 100644
--- a/liblttng-ust-jul/org/lttng/ust/jul/LTTngSessiondCmd2_4.java
+++ b/liblttng-ust-jul/org/lttng/ust/jul/LTTngSessiondCmd2_4.java
@@ -133,7 +133,7 @@ public interface LTTngSessiondCmd2_4 {
 			buf.order(ByteOrder.LITTLE_ENDIAN);
 			lttngLogLevel = buf.getInt();
 			lttngLogLevelType = buf.getInt();
-			name = new String(data, data_offset, data.length - data_offset);
+			name = new String(data, data_offset, data.length - 
+data_offset).trim();
 		}
 
 		@Override
@@ -152,76 +152,32 @@ public interface LTTngSessiondCmd2_4 {
 		 * @return Event name as a string if the event is NOT found thus was
 		 * not enabled.
 		 */
-		public void execute(LTTngLogHandler handler,
-				Map<String, ArrayList<LTTngEvent>> eventMap, Set wildCardSet) {
-			ArrayList<LTTngEvent> bucket;
-			LTTngEvent event;
+		public void execute(LTTngLogHandler handler) {
+			LTTngEvent event, lookupEv;
 
-			if (name == null) {
+			if (this.name == null) {
 				this.code = lttng_jul_ret_code.CODE_INVALID_CMD;
 				return;
 			}
 
-			/* Wild card to enable ALL logger. */
-			if (name.trim().equals("*")) {
-				String loggerName;
-				Enumeration loggers = handler.logManager.getLoggerNames();
-
-				/* Add event to the wildcard set. */
-				wildCardSet.add(new LTTngEvent(name.trim(), lttngLogLevel,
-							lttngLogLevelType));
-
-				/*
-				 * Create an event for each logger found and attach it to the
-				 * handler.
-				 */
-				while (loggers.hasMoreElements()) {
-					loggerName = loggers.nextElement().toString();
-					/* Somehow there is always an empty string at the end. */
-					if (loggerName == "") {
-						continue;
-					}
-
-					event = new LTTngEvent(loggerName, lttngLogLevel,
-							lttngLogLevelType);
-					/* Attach event to Log handler to it can be traced. */
-					handler.attachEvent(event);
-
-					/*
-					 * The agent timer call this function with eventMap set to
-					 * null because it already has a reference to an existing
-					 * event so is should not try to add a new one here.
-					 */
-					if (eventMap != null) {
-						bucket = eventMap.get(loggerName);
-						if (bucket == null) {
-							bucket = new ArrayList<LTTngEvent>();
-							eventMap.put(loggerName, bucket);
-						}
-						bucket.add(event);
-					}
-				}
-			} else {
-				event = new LTTngEvent(name.trim(), lttngLogLevel,
-						lttngLogLevelType);
-				/* Attach event to Log handler to it can be traced. */
-				handler.attachEvent(event);
-
-				/*
-				 * The agent timer call this function with eventMap set to
-				 * null because it already has a reference to an existing
-				 * event so is should not try to add a new one here.
-				 */
-				if (eventMap != null) {
-					bucket = eventMap.get(name.trim());
-					if (bucket == null) {
-						bucket = new ArrayList<LTTngEvent>();
-						eventMap.put(name.trim(), bucket);
-					}
-					bucket.add(event);
-				}
+			/*
+			 * Try to remove the logger name from the disabled events set in
+			 * the handler. The return value is of no importance, we just need
+			 * to try it.
+			 */
+			handler.disabledEvents.remove(this.name);
+
+			/* Handler already attached. */
+			if (handler.attached == 1) {
+				this.code = lttng_jul_ret_code.CODE_SUCCESS_CMD;
+				return;
 			}
 
+			/* Get the default JUL root logger and add our handler. */
+			Logger rootLogger = handler.logManager.getLogger("");
+			rootLogger.addHandler(handler);
+			handler.attached = 1;
+
 			this.code = lttng_jul_ret_code.CODE_SUCCESS_CMD;
 			return;
 		}
@@ -238,13 +194,9 @@ public interface LTTngSessiondCmd2_4 {
 
 		@Override
 		public void populate(byte[] data) {
-			int data_offset = INT_SIZE * 2;
-
 			ByteBuffer buf = ByteBuffer.wrap(data);
 			buf.order(ByteOrder.LITTLE_ENDIAN);
-			lttngLogLevel = buf.getInt();
-			lttngLogLevelType = buf.getInt();
-			name = new String(data, data_offset, data.length - data_offset);
+			name = new String(data).trim();
 		}
 
 		@Override
@@ -260,62 +212,21 @@ public interface LTTngSessiondCmd2_4 {
 		 * Execute disable handler action which is to disable the given handler
 		 * to the received name.
 		 */
-		public void execute(LTTngLogHandler handler,
-				Map<String, ArrayList<LTTngEvent>> eventMap, Set wildCardSet) {
-			ArrayList<LTTngEvent> bucket;
+		public void execute(LTTngLogHandler handler) {
 			LTTngEvent event;
 
-			if (name == null) {
+			if (this.name == null) {
 				this.code = lttng_jul_ret_code.CODE_INVALID_CMD;
 				return;
 			}
 
-			/* Wild card to disable ALL logger. */
-			if (name.trim().equals("*")) {
-				String loggerName;
-				Enumeration loggers = handler.logManager.getLoggerNames();
-
-				/* Remove event from the wildcard set. */
-				wildCardSet.remove(new LTTngEvent(name.trim(), lttngLogLevel,
-							lttngLogLevelType));
-
-				while (loggers.hasMoreElements()) {
-					loggerName = loggers.nextElement().toString();
-					/* Somehow there is always an empty string at the end. */
-					if (loggerName == "") {
-						continue;
-					}
-
-					event = new LTTngEvent(loggerName, lttngLogLevel,
-							lttngLogLevelType);
-
-					bucket = eventMap.get(loggerName);
-					if (bucket != null) {
-						handler.detachEvent(event);
-						bucket.remove(event);
-						if (bucket.isEmpty() == true) {
-							eventMap.remove(bucket);
-						}
-					}
-				}
-				this.code = lttng_jul_ret_code.CODE_SUCCESS_CMD;
-			} else {
-				event = new LTTngEvent(this.name, lttngLogLevel,
-						lttngLogLevelType);
-
-				bucket = eventMap.get(this.name);
-				if (bucket != null) {
-					handler.detachEvent(event);
-					bucket.remove(event);
-					if (bucket.isEmpty() == true) {
-						eventMap.remove(bucket);
-					}
-					this.code = lttng_jul_ret_code.CODE_SUCCESS_CMD;
-				} else {
-					this.code = lttng_jul_ret_code.CODE_UNK_LOGGER_NAME;
-				}
+			event = handler.disabledEvents.get(this.name);
+			if (event == null) {
+				handler.disabledEvents.put(this.name,
+						new LTTngEvent(this.name, 0, 0));
 			}
 
+			this.code = lttng_jul_ret_code.CODE_SUCCESS_CMD;
 			return;
 		}
 	}
diff --git a/liblttng-ust-jul/org/lttng/ust/jul/LTTngTCPSessiondClient.java b/liblttng-ust-jul/org/lttng/ust/jul/LTTngTCPSessiondClient.java
index a2d12fc..912d507 100644
--- a/liblttng-ust-jul/org/lttng/ust/jul/LTTngTCPSessiondClient.java
+++ b/liblttng-ust-jul/org/lttng/ust/jul/LTTngTCPSessiondClient.java
@@ -39,8 +39,6 @@ import java.util.Iterator;  import java.util.List;  import java.util.Enumeration;  import java.util.Set; -import java.util.Timer; -import java.util.TimerTask;  import java.util.logging.Logger;  import java.util.Collections;
 
@@ -64,23 +62,6 @@ public class LTTngTCPSessiondClient {
 
 	private Semaphore registerSem;
 
-	private Timer eventTimer;
-
-	/*
-	 * Indexed by event name but can contains duplicates since multiple
-	 * sessions can enable the same event with or without different loglevels.
-	 */
-	private Map<String, ArrayList<LTTngEvent>> eventMap =
-		Collections.synchronizedMap(
-				new HashMap<String, ArrayList<LTTngEvent>>());
-
-	private Set<LTTngEvent> wildCardSet =
-		Collections.synchronizedSet(new HashSet<LTTngEvent>());
-
-	/* Timer delay at each 5 seconds. */
-	private final static long timerDelay = 5 * 1000;
-	private static boolean timerInitialized;
-
 	private static final String rootPortFile = "/var/run/lttng/jul.port";
 	private static final String userPortFile = "/.lttng/jul.port";
 
@@ -90,83 +71,6 @@ public class LTTngTCPSessiondClient {
 	public LTTngTCPSessiondClient(String host, Semaphore sem) {
 		this.sessiondHost = host;
 		this.registerSem = sem;
-		this.eventTimer = new Timer();
-		this.timerInitialized = false;
-	}
-
-	private void setupEventTimer() {
-		if (this.timerInitialized) {
-			return;
-		}
-
-		this.eventTimer.scheduleAtFixedRate(new TimerTask() {
-			@Override
-			public void run() {
-				LTTngSessiondCmd2_4.sessiond_enable_handler enableCmd = new
-					LTTngSessiondCmd2_4.sessiond_enable_handler();
-
-				synchronized (eventMap) {
-					String loggerName;
-					Enumeration loggers = handler.logManager.getLoggerNames();
-
-					/*
-					 * Create an event for each logger found and attach it to the
-					 * handler.
-					 */
-					while (loggers.hasMoreElements()) {
-						ArrayList<LTTngEvent> bucket;
-
-						loggerName = loggers.nextElement().toString();
-
-						/* Logger is already enabled or end of list, skip it. */
-						if (handler.exists(loggerName) == true ||
-								loggerName.equals("")) {
-							continue;
-						}
-
-						bucket = eventMap.get(loggerName);
-						if (bucket == null) {
-							/* No event(s) exist for this logger. */
-							continue;
-						}
-
-						for (LTTngEvent event : bucket) {
-							enableCmd.name = event.name;
-							enableCmd.lttngLogLevel = event.logLevel.level;
-							enableCmd.lttngLogLevelType = event.logLevel.type;
-
-							/* Event exist so pass null here. */
-							enableCmd.execute(handler, null, wildCardSet);
-						}
-					}
-				}
-
-				/* Handle wild cards. */
-				synchronized (wildCardSet) {
-					Map<String, ArrayList<LTTngEvent>> modifiedEvents =
-						new HashMap<String, ArrayList<LTTngEvent>>();
-					Set<LTTngEvent> tmpSet = new HashSet<LTTngEvent>();
-					Iterator<LTTngEvent> it = wildCardSet.iterator();
-
-					while (it.hasNext()) {
-						LTTngEvent event = it.next();
-
-						/* Only support * for now. */
-						if (event.name.equals("*")) {
-							enableCmd.name = event.name;
-							enableCmd.lttngLogLevel = event.logLevel.level;
-							enableCmd.lttngLogLevelType = event.logLevel.type;
-
-							/* That might create a new event so pass the map. */
-							enableCmd.execute(handler, modifiedEvents, tmpSet);
-						}
-					}
-					eventMap.putAll(modifiedEvents);
-				}
-			}
-		}, this.timerDelay, this.timerDelay);
-
-		this.timerInitialized = true;
 	}
 
 	/*
@@ -185,8 +89,6 @@ public class LTTngTCPSessiondClient {
 	 * Cleanup Agent state.
 	 */
 	private void cleanupState() {
-		eventMap.clear();
-		wildCardSet.clear();
 		if (this.handler != null) {
 			this.handler.clear();
 		}
@@ -216,8 +118,6 @@ public class LTTngTCPSessiondClient {
 				 */
 				registerToSessiond();
 
-				setupEventTimer();
-
 				/*
 				 * Block on socket receive and wait for command from the
 				 * session daemon. This will return if and only if there is a @@ -239,7 +139,6 @@ public class LTTngTCPSessiondClient {
 
 	public void destroy() {
 		this.quit = true;
-		this.eventTimer.cancel();
 
 		try {
 			if (this.sessiondSock != null) {
@@ -331,7 +230,7 @@ public class LTTngTCPSessiondClient {
 						break;
 					}
 					enableCmd.populate(data);
-					enableCmd.execute(this.handler, this.eventMap, this.wildCardSet);
+					enableCmd.execute(this.handler);
 					data = enableCmd.getBytes();
 					break;
 				}
@@ -344,7 +243,7 @@ public class LTTngTCPSessiondClient {
 						break;
 					}
 					disableCmd.populate(data);
-					disableCmd.execute(this.handler, this.eventMap, this.wildCardSet);
+					disableCmd.execute(this.handler);
 					data = disableCmd.getBytes();
 					break;
 				}
--
2.0.0


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