Is it possible for using different pattern layout for different log level and output to SYSTEM_OUT?

Question

For log4j2, is it possible for using different pattern layout for different log level and output to SYSTEM_OUT?

Here is my log4j2.xml:

    <?xml version="1.0" encoding="UTF-8"?>
    <Configuration>
        <Appenders>
            <Console name="debugMsg" target="SYSTEM_OUT">
                <PatternLayout pattern="[%-5level] %d{yyyy-MM-dd HH:mm:ss.SSS} %l - %msg%n"/>
            </Console>
            <Console name="infoMsg" target="SYSTEM_OUT">
                <PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss.SSS} %msg%n"/>
            </Console>
        </Appenders>
        <Loggers>
            <Root level="trace"  additivity="false">
                <AppenderRef ref="infoMsg" level="info"/>
                <AppenderRef ref="debugMsg" level="debug"/>
            </Root>
        </Loggers>
    </Configuration>

However, the INFO level message are shown in both "infoMsg" and "debugMsg" pattern.

2015-12-24 10:51:56.176 Log4j is ready.
[INFO ] 2015-12-24 10:51:56.176 com.myftpserver.MyFtpServer.<init>(MyFtpServer.java:65) - Log4j is ready.
2015-12-24 10:51:56.176 Configuration file is loaded
[INFO ] 2015-12-24 10:51:56.176 com.myftpserver.Configuration.load(Configuration.java:74) - Configuration file is loaded
[DEBUG] 2015-12-24 10:51:56.176 com.myftpserver.Configuration.load(Configuration.java:82) - supportPassiveMode=true
2015-12-24 10:51:56.301 User Manager class is loaded.
[INFO ] 2015-12-24 10:51:56.301 com.myftpserver.Configuration.load(Configuration.java:119) - User Manager class is loaded.
2015-12-24 10:51:56.301 File Manager class is loaded.
[INFO ] 2015-12-24 10:51:56.301 com.myftpserver.Configuration.load(Configuration.java:121) - File Manager class is loaded.
2015-12-24 10:51:56.301 Server Initialization completed.
[INFO ] 2015-12-24 10:51:56.301 com.myftpserver.MyFtpServer.<init>(MyFtpServer.java:69) - Server Initialization completed.
2015-12-24 10:51:56.301 Available passive port:[1232, 1233, 1234]
[INFO ] 2015-12-24 10:51:56.301 com.myftpserver.MyFtpServer.<init>(MyFtpServer.java:75) - Available passive port:[1232, 1233, 1234]

So, is it possible to remove duplicate item?

thank you very much and Merry X'mas

Answer 1

The latest versions of Log4j2 allow a pattern selector instead of just a single pattern. Log4j provides a selector based on markers but not one based on levels. Create a Jira issue and I will add it. However, Log4j does allow you to used a script to select the pattern. It would be simple to write one that selects based on the level.

In the configuration above the debug appender is also going to output info level events, which is why you see the duplicates.

I haven't tested it but I believe the configuration below should do what you want:

<?xml version="1.0" encoding="UTF-8"?>
<Configuration>
    <Appenders>
        <Console name="Console" target="SYSTEM_OUT">
            <PatternLayout>
                <ScriptPatternSelector defaultPattern="[%-5level] %d{yyyy-MM-dd HH:mm:ss.SSS} %l - %msg%n">
                    <Script name="LevelSelector" language="bsh"><![CDATA[
                        if (logEvent.getLevel() == org.apache.logging.log4j.Level.INFO) {
                            return "INFO";
                        } 
                        return null;
                        ]]>
                    </Script>
                    <PatternMatch key="INFO" pattern="%d{yyyy-MM-dd HH:mm:ss.SSS} %msg%n"/>
                </ScriptPatternSelector>
            </PatternLayout>
        </Console> 
    </Appenders>
    <Loggers>
        <Root level="trace">
            <AppenderRef ref="Console"/>
        </Root>
    </Loggers>
</Configuration>

Answer 2

Yes. Since log4j 2.13 there is the LevelPatternSelector. You can use it like that.

I use the error/fatal case as default pattern. You can also specify it explicite.

      <Console name="stdout" target="SYSTEM_OUT">
         <PatternLayout>
            <LevelPatternSelector defaultPattern="%highlight{[%p] %d{HH:mm:ss} %c:%L %m}{bright,red}%n">
               <PatternMatch key="WARN" pattern="%highlight{[%p] %d{HH:mm:ss} %c:%L %m}{bright,yellow}%n" />
               <PatternMatch key="INFO" pattern="[%style{%p}{blue}] %d{HH:mm:ss} %c:%L %m%n" />
               <PatternMatch key="DEBUG" pattern="[%p] %d{HH:mm:ss} %c:%L %m%n" />
               <PatternMatch key="TRACE" pattern="[%p] %d{HH:mm:ss} %c:%L %m%n" />
            </LevelPatternSelector>
         </PatternLayout>
      </Console>