Block logging for assemblies having separate loggers in log4net

Question

I have two log files written from my application, which have multiple assemblies in the following manner:

Assembly1 log -> MainLog.log
Assembly2 log -> MainLog.log
Assembly3 log -> MainLog.log
Assembly4 log -> MainLog.log
Assembly5 log -> SubLog.log
Assembly6 log -> SubLog.log

The log files get written correctly, but the problem here is, the SubLog entries get written into the MainLog file as well. I don't want this kind of logging duplication to happen. This is my log4net configuration.

<log4net>
    <appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">
        <file value="Logs//MainLog.txt" />
        <appendToFile value="true" />
        <maxSizeRollBackups value="10" />
        <maximumFileSize value="100KB" />
        <rollingStyle value="Size" />
        <staticLogFileName value="true" />
        <layout type="log4net.Layout.PatternLayout">
            <conversionPattern value="%M %date [%thread] %-5level %logger [%ndc] - %message        %C, %F, %l, %L  %M %newline" />
        </layout>
    </appender>
    <appender name="NewForEveryRun" type="log4net.Appender.FileAppender">
        <file type="log4net.Util.PatternString" value="Logs//SubLog-%processid.txt"/>
        <appendToFile value="true" />
        <maximumFileSize value="10MB" />
        <staticLogFileName value="true" />
        <layout type="log4net.Layout.PatternLayout">
            <conversionPattern value="%date [%thread] %-5level %logger - %message%newline" />
        </layout>
    </appender>
    <logger name="Assembly5">
        <level value="DEBUG"/>
        <appender-ref ref="NewForEveryRun"/>
    </logger>
    <logger name="Assembly6">
        <level value="DEBUG"/>
        <appender-ref ref="NewForEveryRun"/>
    </logger>
    <root>
        <level value="DEBUG" />
        <appender-ref ref="RollingLogFileAppender" />
    </root>

For Assembly5 and Assembly6, I've specified the appender NewForEveryRun. In addition to this, I've kept the root, so that the rest of the assemblies are logged according to configuration specified in the RollingLogFileAppender appender. I guess, the root element is logging all the assemblies by default, even if I mention different logger for other assemblies. Is there any way to block the logging of Assembly5 and Assembly6 from root?

Answer 1

Got it! The loggers should look like this:

<logger name="Assembly5" additivity="false">
    <level value="DEBUG"/>
    <appender-ref ref="NewForEveryRun"/>
</logger>
<logger name="Assembly6" additivity="false">
    <level value="DEBUG"/>
    <appender-ref ref="NewForEveryRun"/>
</logger>

Setting additivity as false is the solution. No more duplicate logging :)