How to do programmatic configuration for log4j2 RollingFileAppender

Question

I am using log4j2 programmatically without a configuration file, but configuring it in code. I'm trying to use the log4j2 RollingFileAppender to save the last 10 log files. I tried limiting the file size using the SizeBasedTriggeringPolicy. The size limitation works but it doesn't create old log files and just keeps deleting and writing to the one original log file.

public static void configLog() {
        String dir = System.getProperty("java.io.tmpdir") + "test\\";
        final LoggerContext ctx = (LoggerContext) LogManager.getContext(false);
        final Configuration config = ctx.getConfiguration();
        PatternLayout layout = PatternLayout.newBuilder().withConfiguration(config).withPattern(PatternLayout.SIMPLE_CONVERSION_PATTERN).build();
        SizeBasedTriggeringPolicy policy = SizeBasedTriggeringPolicy.createPolicy("1KB");
        DefaultRolloverStrategy strategy = DefaultRolloverStrategy.createStrategy("10", "0", null, null, config);
        RollingFileManager fileManager = RollingFileManager.getFileManager(dir + "log\\test.log", dir + "log\\test-%i.log", false, false, policy, strategy, null, layout, 128);
        policy.initialize(fileManager);
        RollingFileAppender appender = RollingFileAppender.createAppender(dir + "log\\test.log", dir + "log\\test-%i.log",
                "false", "File", "false", "128", "true", policy, strategy, layout, (Filter) null, "false", "false", (String) null, config);
        appender.start();
        config.addAppender(appender);
        AppenderRef ref = AppenderRef.createAppenderRef("File", Level.INFO, null);
        AppenderRef[] refs = new AppenderRef[] { ref };
        LoggerConfig loggerConfig = LoggerConfig.createLogger("true", Level.INFO, LogManager.ROOT_LOGGER_NAME, "true",
                refs, null, config, null);
        loggerConfig.addAppender(appender, Level.INFO, null);
        config.addLogger(LogManager.ROOT_LOGGER_NAME, loggerConfig);
        ctx.updateLoggers();
    }

I didn't manage to find a lot of examples configuring the logging with java but i need to for my application. The example from where I took most of the code is here http://logging.apache.org/log4j/2.x/manual/customconfig.html (the second code part).

Why doesn't it create/save old log files?

alan7678 alan7678 · Accepted Answer · 2015-06-15T21:13:29

Even though this is an old question others may find it useful, i believe it to be because

RollingFileAppender.createAppender(dir + "log\\test.log", dir + "log\\test-%i.log",
            "false", "File", "false", "128", "true", policy, strategy, layout, (Filter) null, "false", "false", (String) null, config);

should be

RollingFileAppender.createAppender(dir + "log\\test.log", dir + "log\\test-%i.log",
            "true", "File", "false", "128", "true", policy, strategy, layout, (Filter) null, "false", "false", (String) null, config);

The third argument is the append option https://logging.apache.org/log4j/2.x/log4j-core/apidocs/org/apache/logging/log4j/core/appender/RollingFileAppender.html

How to do programmatic configuration for log4j2 RollingFileAppender

1 Answers