Logback files

CustomFilter.java

public class CustomFilter extends Filter<ILoggingEvent> {



	private Set<String> customizedUsersSet;



	public FilterReply decide(ILoggingEvent event) {
		//deny anything but a user filtered by CustomTurboFilter

		if (!isStarted() || customizedUsersSet == null)

			return FilterReply.DENY;



		String user = MDC.get("userId");

		if (user == null)

			return FilterReply.DENY;


		return customizedUsersSet.contains(user) ? FilterReply.NEUTRAL : FilterReply.DENY;

	}



	public void start() {
		//FIXME is this safe? Joran's sequential processing seems to make it so
		Iterator<TurboFilter> iterator = ((LoggerContext) getContext()).getTurboFilterList().iterator();

		while (iterator.hasNext()) {

			TurboFilter tf = iterator.next();

			if (tf instanceof CustomTurboFilter) {

				customizedUsersSet = ((CustomTurboFilter) tf).getCustomizedUsersSet();

				addInfo("Allowed users: " + customizedUsersSet);

				break;

			}

		}

		if (customizedUsersSet == null)

			addWarn("No matching TurboFilter found");

		super.start();

	}



}

CustomTurboFilter.java

public class CustomTurboFilter extends TurboFilter {



	private Map<String,Map<String,Level>> userCustomizationsMap = new HashMap<String, Map<String,Level>>();

	private Set<String> customizedUsersSet;



	public FilterReply decide(Marker marker, Logger logger, Level level, String format, Object[] params, Throwable throwable) {

		if (!isStarted())

			return FilterReply.NEUTRAL;

	

		String user = MDC.get("userId");

		if (user == null)

			return FilterReply.NEUTRAL;



		Map<String, Level> map = userCustomizationsMap.get(user);

		if (map == null)

			return FilterReply.NEUTRAL; //undefined user

	

		//test each logger-level for this user, find the closest match to 'logger'

		String loggerName = logger.getName();

		Level specificLoggerLevel = null;

		int specificLoggerNameLength = -1;

		for (Entry<String, Level> e : map.entrySet()) {

			String name = e.getKey();

			//FIXME This is awful code, I know, but I found no other way to check logger hierarchy (and LoggerComparator is not fit for this)
			//FIXME guess it could be a bit faster using only 'startsWith', 'length' and 'charAt', but still String manipulation

			if (loggerName.equals(name)) {

				specificLoggerLevel = e.getValue(); //exact logger match

				break;

			}
			//FIXME Here I attempt to find the most specific logger definition for the current logger (awful too)

			int length = name.length();

			if (loggerName.startsWith(name+".") && length > specificLoggerNameLength) {
				//the logger in this definition is a parent of 'logger', and longer name than the last one

				specificLoggerNameLength = length; 

				specificLoggerLevel = e.getValue();

			}

		}

		if (specificLoggerLevel != null && level.isGreaterOrEqual(specificLoggerLevel)) {

			return FilterReply.ACCEPT; //match found, force accept

		} else {

			return FilterReply.NEUTRAL; //no matching logger found, ignore

		}

	}



	public void addUserCustomization(UserLoggersMapping userLoggersMapping) {

		String user = userLoggersMapping.getUser();

		user = (user == null ? "" : user.trim());

		if (!user.isEmpty() && !userCustomizationsMap.containsKey(user)) {

			Map<String,Level> loggerLevelMap = new HashMap<String, Level>();

			for (LoggerLevelPair llp : userLoggersMapping.getLoggerLevelList()) {

				String logger = llp.getLogger();

				logger = (logger == null ? "" : logger.trim());

				if (!logger.isEmpty() && !loggerLevelMap.containsKey(logger) && llp.getLevel() != null) {

					addInfo("Logger["+logger+"] level customized to "+llp.getLevel()+" for user "+user);

					loggerLevelMap.put(logger, llp.getLevel());

				}

			}

			if (!loggerLevelMap.isEmpty()) {

				userCustomizationsMap.put(user, loggerLevelMap);

			}

		}

	}


	public Set<String> getCustomizedUsersSet() {

		return customizedUsersSet;

	}



	public void start() {

		customizedUsersSet = Collections.unmodifiableSet(userCustomizationsMap.keySet()); //Will be used by CustomFilter

		super.start();

	}



	//Just JavaBeans, also shortening the code :-P

	public static class UserLoggersMapping {

		private String user;

		private List<LoggerLevelPair> loggerLevelList = new ArrayList<LoggerLevelPair>();

		private String getUser() {return user;}

		public void setUser(String user) {this.user = user;}

		private List<LoggerLevelPair> getLoggerLevelList() {return loggerLevelList;}

		public void addLoggerLevel(LoggerLevelPair levelLoggerPair) {loggerLevelList.add(levelLoggerPair);}

	}



	public static class LoggerLevelPair {

		private Level level;

		private String logger;

		private Level getLevel() {return level;}

		public void setLevel(Level level) {this.level = level;}

		private String getLogger() {return logger;}

		public void setLogger(String logger) {this.logger = logger;}

	}

}

logback.xml

<configuration debug="true">

	<turboFilter class="com.sample.project.CustomTurboFilter">
		<userCustomization>
			<user>ID_USER_1</user>
			<loggerLevel>
				<logger>com.sample.project</logger>
				<level>DEBUG</level>
			</loggerLevel>
			<loggerLevel>
				<logger>com.sample.legacy</logger>
				<level>INFO</level>
			</loggerLevel>
		</userCustomization>
		<userCustomization>
			<user>ID_USER_2</user>
			<loggerLevel>
				<logger>com.sample.project</logger>
				<level>TRACE</level>
			</loggerLevel>
			...
		</userCustomization>
	</turboFilter>

	<appender name="FILTERED" class="ch.qos.logback.classic.sift.SiftingAppender">
		<discriminator class="ch.qos.logback.classic.sift.MDCBasedDiscriminator">
			<key>userId</key>
			<defaultValue>unknown</defaultValue>
		</discriminator>

		<filter class="com.sample.project.CustomFilter"/>

		<sift> ... </sift>
	</appender>


	<logger name="com.sample.project" level="WARN">
		<appender-ref ref="FILTERED" />
	</logger>
	<root level="WARN">
		<appender-ref ref="STANDARD" />
	</root>

</configuration>