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logginglogback

Logback default value when runtime parameter is not supplied

I have this conf in my logback.xml:

<logger name="L1" additivity="false">
    <appender-ref ref="${SELECTED_CONSOLE}" />
</logger>

<root level="${LOG_LEVEL}">
    <appender-ref ref="${SELECTED_CONSOLE}" />
</root>

My issue is, on some env, if the LOG_LEVEL var hasn't been defined, what will the level of log of L1 be?

Solution

  • If the LOG_LEVEL parameter is undefined then Logback will treat that as this string:

    LOG_LEVEL_IS_UNDEFINED

    Logback will then turn that value into ch.qos.logback.classic.Level.DEBUG (see the implementation of ch.qos.logback.classic.Level.toLevel())

    So, your root logger level will be DEBUG and since the L1 logger has no level declared it will inherit that level. So, if LOG_LEVEL is not defined then the log level for L1 will be: DEBUG.

    The fact that L1's additivity is false does not change this; additivity prevents parents of the L1 logger from using their appenders to display the message, it does not affect the inferred log level.