How to create 2 different ROOT loggers with logback?

Question

I'm happily using SLF4J with logback and use 2 appenders for the ROOT logger.

<root level="DEBUG">     <appender-ref ref="STDOUT" />     <appender-ref ref="FILE" /> </root> 

How could we have different log-levels for both appenders? I still need all ROOT-logger messages.

• DEBUG-level for STDOUT
• INFO-level for FILE

All log's need to be part of the output (so the ROOT logger is needed).

Answer 1

You will not ever have more than one root-logger, so your question is a bit misleading. What you are looking for is how to fine-tune which events each of the appenders does log.

And for that, you add a ThresholdFilter to each of the appenders:

http://logback.qos.ch/manual/filters.html#thresholdFilter

<filter class="ch.qos.logback.classic.filter.ThresholdFilter">   <level>INFO</level> </filter> 

Configure level INFO for the FILE-appender and DEBUG for STDOUT.

Edit: I have to dispute the other answer's charge that this one is wrong: Yes, you can have more than one root-element in the configuration. That does not create more than one root-logger though, which was what the question's title asks for. Also, the logback manual states under http://logback.qos.ch/manual/configuration.html#syntax (highlighting mine):

Nevertheless, the very basic structure of the configuration file can be described as, < configuration > element, followed by zero or more < appender > elements, followed by zero or more < logger > elements, followed by at most one < root > element.

It might work, but at the very least it's against convention.

Answer 2

You can have multiple root elements, each with an associated logging level and an appender-ref (I'm working with logback.version>1.0.13) In this case you also have to put a FILTER inside yours appenders, like that:

<contextListener class="ch.qos.logback.classic.jul.LevelChangePropagator">     <resetJUL>true</resetJUL> </contextListener>  <!-- To enable JMX Management --> <jmxConfigurator/>  <appender name="console-info" class="ch.qos.logback.core.ConsoleAppender">    <filter class="ch.qos.logback.classic.filter.LevelFilter">      <level>INFO</level>      <onMatch>ACCEPT</onMatch>      <onMismatch>DENY</onMismatch>   </filter>   <encoder>         <pattern>%-4relative [%thread] %-5level %logger{35} - %msg %n</pattern>   </encoder> </appender>    <appender name="console-debug" class="ch.qos.logback.core.ConsoleAppender">   <filter class="ch.qos.logback.classic.filter.LevelFilter">      <level>DEBUG</level>      <onMatch>ACCEPT</onMatch>      <onMismatch>DENY</onMismatch>   </filter>   <encoder>       <pattern>[%d{ddMMMyyyy HH:mm:ss.SS}]%-5level %logger{45} - %msg %n</pattern>   </encoder> </appender>   <root level="info">     <appender-ref ref="console-info"/> </root> <root level="debug">     <appender-ref ref="console-debug"/> </root>