I'm trying to write logs into different files for each Thread/ThreadGroup. My code is creating different files for each thread, but it writing all other threads logs into one file.

MainTest.java

public class MainTest {
    public static void main(String[] args) {
        ThreadGroup tg1 = new ThreadGroup("Group A");

        Thread t1 = new Thread(tg1, new LoggingTest(), "t1");
        t1.start();

        Thread t2 = new Thread(tg1, new LoggingTest(), "t2");
        t2.start();

        //
        Thread t3 = new Thread(new LoggingTest(),"t3");
        t3.start();
    }
}

LoggingTest.java

public class LoggingTest implements Runnable {
    private static final Logger logger      = LogManager.getLogger(LoggingTest.class);
    private static final String logFilePath = "/output/logs/";
    private static final String pattern     = "%d{dd MMM yyyy HH:mm:ss.SSS} (%F:%L) - %m%n";

    public void run() {
        Thread runner         = Thread.currentThread();
        
        LoggerContext context = (org.apache.logging.log4j.core.LoggerContext) LogManager.getContext(false);
        try {
            URL configFile    = LoggingTest.class.getResource("/log4j2.properties");
            context.setConfigLocation(configFile.toURI());
        }catch(Exception e) {
            e.printStackTrace();
        }
        
        LoggerContext ctx     = (LoggerContext) LogManager.getContext(false);
        FileAppender appender = null;
        try {
            appender = FileAppender
                    .newBuilder()
                    .setName("Name")
                    .setLayout(PatternLayout.newBuilder().withPattern(pattern).build())
                    .withFileName(logFilePath   runner.getName()   ".log")
                    .build();
        } catch (Exception e) {
            logger.error("error -> " e);
        }
        
        if (appender != null) {
            if ( runner.getThreadGroup().getParent() != null )
            {
                appender.addFilter( new ThreadGroupFilter( runner.getThreadGroup() ) );
            }
            else
            {
                appender.addFilter( new ThreadFilter( runner ) );
            }
            appender.start();
            ctx.getRootLogger().addAppender(appender);
            ctx.updateLoggers();
        }

        logger.info("info msg");
        logger.debug("debug msg");
        logger.error("error msg");

        if ( appender != null ) {
            ctx.getRootLogger().removeAppender(appender);
            ctx.updateLoggers();
            appender.stop();
        }
    }
}

Here I created couple of filter classes for both Thread & ThreadGroup. But seems like these are not working properly. ThreadGroupFilter.java

import org.apache.logging.log4j.core.Filter;  

public class ThreadGroupFilter implements Filter {
        
        private final ThreadGroup filterThreadGroup;
    
        public ThreadGroupFilter( ThreadGroup filterThreadGroup ) {
            this.filterThreadGroup = filterThreadGroup;
        }
    
        @Override
        public Result filter(LogEvent event) {
            if ( Thread.currentThread().getThreadGroup() != filterThreadGroup )
                return Filter.Result.DENY;
    
            return Filter.Result.NEUTRAL;
        }
    }

ThreadFilter.java

public class ThreadFilter implements Filter {
    private final Thread filterThread;

    public ThreadFilter( Thread filterThread ) {
        this.filterThread = filterThread;
    }
    
    @Override
    public Result filter(LogEvent event) {
        if ( Thread.currentThread() != filterThread )
            return Filter.Result.DENY;

        return Filter.Result.NEUTRAL;
    }
}

log4j2.properties

name=PropertiesConfig
property.basePath = ../logs

appenders = console

appender.console.type = Console
appender.console.name = consoleLogger
appender.console.layout.type = PatternLayout
appender.console.layout.pattern = %5p [%c] [%t] (%F:%L) - %m%n

rootLogger.level = debug
rootLogger.appenderRefs = console
rootLogger.appenderRef.stdout.ref = consoleLogger

I'm expecting multiple log files for each Thread/ThreadGroup. But I'm ended up with multiple log files for each Thread and all threads logs into one file.

Thank you in advance.

CodePudding user response：

Each of your threads calls LoggerContext#setConfigLocation, which causes a reconfiguration of Log4j2. The reconfiguration removes all the appenders you added programmatically. That is why you end up with a single appender.

Remark that you do not need programmatic configuration to have a different file appender per thread. You can just use the RoutingAppender as in this question.

Edit: If you really want to use programmatic configuration (which is discouraged for compatibility reasons), you also need to use a unique name for each appender, otherwise they will be silently ignored (the Logger#addAppender method you use is not part of the public API, cf. javadoc, so errors are not reported).

CodePudding user response：

move this piece of code from LoggingTest to MainTest

LoggerContext context = (org.apache.logging.log4j.core.LoggerContext) LogManager.getContext(false);
try {
    URL configFile    = LoggingTest.class.getResource("/log4j2.properties");
    context.setConfigLocation(configFile.toURI());
}catch(Exception e) {
    e.printStackTrace();
}

And minor modifications at Appender configuration.

FileAppender appender = null;
String appenderName = (runner.getThreadGroup() != null) ? "appender_" runner.getThreadGroup().getName() : "appender_" runner.getName();
try {
    appender = FileAppender
            .newBuilder()
            .setName(appenderName)
            .setLayout(PatternLayout.newBuilder().withPattern(pattern).build())
            .withFileName(logFilePath   appenderName   ".log")
            .build();
} catch (Exception e) {
    logger.error("error -> " e);
}

Thanks for the solution Poitr P. Karwasz