Failure to add a custom converter to log4j

Question

Following here, I'd like to extend log4j by a custom convertor, to add the shiro user name to the log. Here's my code:

@Plugin(name = "shiro", type = "Converter")
@ConverterKeys({"susr", "shiro"})
public class ShiroUserConverter extends LogEventPatternConverter {

private static final ShiroUserConverter INSTANCE = new ShiroUserConverter();

private ShiroUserConverter()
{
    this("shiro", "shiro"); // not sure why!
}

protected ShiroUserConverter(String name, String style) {
    super(name, style);
}

public static ShiroUserConverter newInstance(final String[] options) {
    return INSTANCE;
} 

@Override
public void format(LogEvent arg0, StringBuilder arg1) {
    // TODO Auto-generated method stub
    Subject currentUser = SecurityUtils.getSubject();

    if ( currentUser != null && currentUser.getPrincipal() != null)
        arg1.append(currentUser.getPrincipal().toString());
    else
        arg1.append("No User");
}

}

The configuration file is as follows:

<?xml version="1.0" encoding="UTF-8"?>
<configuration status="debug">
  <appenders>
    <File name="A1" fileName="/tmp/logs/A1.log" append="false">
      <PatternLayout pattern="%d %-5p [%t] [%susr] %C{2} (%F:%L) - %m%n"/>
    </File>
    <Console name="STDOUT" target="SYSTEM_OUT">
      <PatternLayout pattern="%d %-5p [%t] [%susr] %C{2} (%F:%L) - %m%n"/>
    </Console>
  </appenders>
  <loggers>
    <logger name="org.apache.log4j.xml" level="debug">
      <appender-ref ref="A1"/>
    </logger>
    <root level="debug">
      <appender-ref ref="A1"/>
    </root>
  </loggers>
</configuration>

The problem is that log4j does not pick up my custom convertor. When I debug it, I get the following error message:

ERROR Unrecognized format specifier [susr]
ERROR Unrecognized conversion specifier [susr] starting at position 19 in conversion pattern.

I even put my class in the same package package org.apache.log4j.pattern; but still no luck. Any help would be appreciated.

-- Edit: This is the full console output:

2013-08-09 16:55:01,370 DEBUG Found Plugin Map at jar:file:/Users/path/to/log4j-core-2.0-beta5.jar!/org/apache/logging/log4j/core/config/plugins/Log4j2Plugins.dat
2013-08-09 16:55:01,373 DEBUG Generated plugins in 0.003793000 seconds
2013-08-09 16:55:01,374 DEBUG Generated plugins in 0.000551000 seconds
2013-08-09 16:55:01,375 DEBUG Generated plugins in 0.000548000 seconds
2013-08-09 16:55:01,376 DEBUG Generated plugins in 0.000555000 seconds
2013-08-09 16:55:01,377 DEBUG Generated plugins in 0.000546000 seconds
2013-08-09 16:55:01,378 DEBUG Generated plugins in 0.000540000 seconds
2013-08-09 16:55:01,379 DEBUG Generated plugins in 0.000546000 seconds
2013-08-09 16:55:01,380 DEBUG Generated plugins in 0.000548000 seconds
2013-08-09 16:55:01,381 DEBUG Generated plugins in 0.000556000 seconds
2013-08-09 16:55:01,382 DEBUG Generated plugins in 0.000552000 seconds
2013-08-09 16:55:01,390 DEBUG Calling createLayout on class org.apache.logging.log4j.core.layout.PatternLayout for element PatternLayout with params(pattern="%d %-5p [%t] %susr %C{2} (%F:%L) - %m%n", Configuration(/Users/path/to/target/classes/WEB-INF/log4j.properties), null, charset="null")
2013-08-09 16:55:01,392 DEBUG Generated plugins in 0.000585000 seconds
2013-08-09 16:55:01,392 ERROR Unrecognized format specifier [susr]
2013-08-09 16:55:01,393 ERROR Unrecognized conversion specifier [susr] starting at position 18 in conversion pattern.
2013-08-09 16:55:01,399 DEBUG Calling createAppender on class org.apache.logging.log4j.core.appender.FileAppender for element File with params(fileName="/tmp/logs/A1.log", append="true", locking="null", name="A1", immediateFlush="null", suppressExceptions="null", bufferedIO="null", PatternLayout(%d %-5p [%t] %susr %C{2} (%F:%L) - %m%n), null, advertise="null", advertiseURI="null", Configuration(/Users/path/to/target/classes/WEB-INF/log4j.properties))
2013-08-09 16:55:01,401 DEBUG Starting FileManager /tmp/logs/A1.log
2013-08-09 16:55:01,402 DEBUG Calling createLayout on class org.apache.logging.log4j.core.layout.PatternLayout for element PatternLayout with params(pattern="%d %-5p [%t] [%susr] %C{2} (%F:%L) - %m%n", Configuration(/Users/path/totarget/classes/WEB-INF/log4j.properties), null, charset="null")
2013-08-09 16:55:01,403 ERROR Unrecognized format specifier [susr]
2013-08-09 16:55:01,403 ERROR Unrecognized conversion specifier [susr] starting at position 19 in conversion pattern.
2013-08-09 16:55:01,405 DEBUG Calling createAppender on class org.apache.logging.log4j.core.appender.ConsoleAppender for element Console with params(PatternLayout(%d %-5p [%t] [%susr] %C{2} (%F:%L) - %m%n), null, target="SYSTEM_OUT", name="STDOUT", follow="null", suppressExceptions="null")
2013-08-09 16:55:01,405 DEBUG Calling createAppenders on class org.apache.logging.log4j.core.config.plugins.AppendersPlugin for element appenders with params(appenders={A1, STDOUT})
2013-08-09 16:55:01,407 DEBUG Generated plugins in 0.000665000 seconds
2013-08-09 16:55:01,407 DEBUG Calling createAppenderRef on class org.apache.logging.log4j.core.config.AppenderRef for element appender-ref with params(ref="A1", level="null", null)
2013-08-09 16:55:01,409 DEBUG Calling createLogger on class org.apache.logging.log4j.core.config.LoggerConfig for element logger with params(additivity="null", level="debug", name="org.apache.log4j.xml", includeLocation="null", appender-ref={org.apache.logging.log4j.core.config.AppenderRef@f818d7}, properties={}, Configuration(/Users/path/to/target/classes/WEB-INF/log4j.properties), null)
2013-08-09 16:55:01,410 DEBUG Calling createAppenderRef on class org.apache.logging.log4j.core.config.AppenderRef for element appender-ref with params(ref="A1", level="null", null)
2013-08-09 16:55:01,411 DEBUG Calling createLogger on class org.apache.logging.log4j.core.config.LoggerConfig$RootLogger for element root with params(additivity="null", level="debug", includeLocation="null", appender-ref={org.apache.logging.log4j.core.config.AppenderRef@530ababd}, properties={}, Configuration(/Users/path/to/target/classes/WEB-INF/log4j.properties), null)
2013-08-09 16:55:01,412 DEBUG Calling createLoggers on class org.apache.logging.log4j.core.config.plugins.LoggersPlugin for element loggers with params(loggers={org.apache.log4j.xml, root})

Answer 1

Change your configuration line to

<configuration status="debug" packages="path.to.ShiroUserConverterDirectory">

Just to be clear, packages is the directory containing the class, not the class itself.

I got the following to work:

package com.test.util;
import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.config.plugins.Plugin;
import org.apache.logging.log4j.core.pattern.ConverterKeys;
import org.apache.logging.log4j.core.pattern.LogEventPatternConverter;

@Plugin(name = "shiro", category = "Converter")
@ConverterKeys({"susr", "shiro"})
public class ShiroUserConverter extends LogEventPatternConverter {

private static final ShiroUserConverter INSTANCE = new ShiroUserConverter();

private ShiroUserConverter()
{
    this("shiro", "shiro"); // not sure why!
}

protected ShiroUserConverter(String name, String style) {
    super(name, style);
}

public static ShiroUserConverter newInstance(final String[] options) {
    return INSTANCE;
}

@Override
public void format(LogEvent arg0, StringBuilder arg1) {
    // TODO Auto-generated method stub
        arg1.append("No User");
}

}

and my log4j2.xml file was the following:

<?xml version="1.0" encoding="UTF-8"?>
<configuration status="debug" packages="com.test.util">
  <appenders>
    <Console name="CA" target="SYSTEM_OUT">
       <PatternLayout pattern="%d %-5p [%t] [%susr] %C{2} (%F:%L) - %m%n"/>
    </Console>
   </appenders>

   <loggers>    
     <root level="debug">
       <appender-ref ref="CA"/>
     </root>
   </loggers>
</configuration>