Log4j - Invalid element or attribute in RollingRandomAccessFile

Question

I'm kind of new to Log4J (and Java in general). I'm trying to output some logs to logstash. I ran into some issues with the logstash's built-in log4j input type. For that reason, I wanted to use the json_event layout approach. While I believe I have everything setup properly, I'm getting an error when I start my app that says:

ERROR: RollingRandomAccessFile contains an invalid element or attribute "layout".

I do not understand why I'm getting this, or how to resolve this. I'm more interested in getting my logs in the json_event format than anything else. Currently, my log4j2.xml file looks like this:

<Configuration status="WARN" monitorInterval="30">
  <Appenders>
    <RollingRandomAccessFile name="RollingFile" fileName="/logs/recent.log"
      filePattern="/logs/$${date:yyyy-MM}/server-%d{yyyy-MM-dd-HH}-%i.log.gz">
      <layout class="net.logstash.log4j.JSONEventLayoutV1" />
      <Policies>
        <TimeBasedTriggeringPolicy interval="4" modulate="true"/>
        <SizeBasedTriggeringPolicy size="100 MB"/>
      </Policies>
    </RollingRandomAccessFile>
    <Async name="AsyncFile">
      <AppenderRef ref="RollingFile"/>
    </Async>
  </Appenders>
  <Loggers>
    <Logger name="com.myApp" level="trace" additivity="false">
      <AppenderRef ref="AsyncFile"/>
    </Logger>
    <Root level="trace">
      <AppenderRef ref="AsyncFile"/>
    </Root>
  </Loggers>
</Configuration>

To start my app, I'm running the following at the command-line:

java -Dlog4j.configurationFile=log4j2.xml -cp "/home/ubuntu/jsonevent-layout-1.6.jar" -Xms256m -Xmx1024m -jar myApp.jar

I've confirmed that the path to jsonevent-layout-1.6.jar is correct. My app successfully logs if I remove the new layout. So, I know that log4j is running properly. I know my app runs just fine. This problem is isolated to using the json_event layout. Can someone please help me get this issue resolved? I'm totally stumped as to what I'm doing wrong.

Thank you

Answer 1

The net.logstash.log4j.JSONEventLayoutV1 from github.com/logstash/log4j-jsonevent-layout does not work with Log4J2. You will find a fork at github.com/maartenbosteels/log4j-jsonevent-layout which is compatible with Log4J2. Unfortunately, it is not in a maven central. So you'll have to solve that. However, once you have it that your log4j2.xml will look something like.

<RollingRandomAccessFile name="RollingFile" fileName="/logs/recent.log"
   filePattern="/logs/$${date:yyyy-MM}/server-%d{yyyy-MM-dd-HH}-%i.log.gz">
   <JSONEventLayoutV1>
   <Policies>
     <TimeBasedTriggeringPolicy interval="4" modulate="true"/>
     <SizeBasedTriggeringPolicy size="100 MB"/>
   </Policies>
</RollingRandomAccessFile>