How to avoid double logging with logback?

Question

In my application, I would like to log some messages coming from my own code in a specific manner compared to all other messages being logged. However I am not sure how can I avoid them also being automatically logged to the logack root logger.

Using this configuration below, I would like to use code like follows (scala) so that I can log certain messages only to that logger.

val logger: Logger = LoggerFactory.getLogger("data-logger")

However in the configuration below, these messages get logged twice, i.e. they are logged also by the root logger. How can I avoid that? must I quite artificially use a different logging level to accomplish something like that with logback?

<configuration>

  <appender name="FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
    <file>logs/activity.log</file>
    <rollingPolicy class="ch.qos.logback.core.rolling.FixedWindowRollingPolicy">
      <fileNamePattern>activity.%i.log.zip</fileNamePattern>
      <minIndex>1</minIndex>
      <maxIndex>10</maxIndex>
    </rollingPolicy>
    <triggeringPolicy class="ch.qos.logback.core.rolling.SizeBasedTriggeringPolicy">
      <maxFileSize>10MB</maxFileSize>
    </triggeringPolicy>
    <encoder>
      <pattern>%msg%n</pattern>
    </encoder>
  </appender>

  <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
    <encoder>
      <pattern>%msg%n</pattern>
    </encoder>
  </appender>

  <appender name="ASYNC" class="ch.qos.logback.classic.AsyncAppender">
    <!-- use discarding threshold of zero to avoid ignoring INFO level messages see docs -->
    <discardingThreshold>0</discardingThreshold>
      <appender-ref ref="FILE" />
  </appender>

  <root level="info">
    <appender-ref ref="STDOUT" />
    <appender-ref ref="ASYNC" />
  </root>

  <logger name="data-logger" level="info">
    <appender-ref ref="STDOUT" />
    <appender-ref ref="ASYNC" />
  </logger>

</configuration>

Had the referenced question been edited to have a title reflecting what it deals with maybe you could say they are duplicate. Just flagging as duplicate without checking the quality of the other, is sloppy and should likely be banned. — matanster, Jun 15 '16 at 08:14

score 42 · Accepted Answer · answered Jun 10 '16 at 10:42

42

Loggers are hierarchical, and any message sent to a logger will be sent to all its ancestors by default. You can disable this behavior by setting additivity=false. E.g.:

<logger name="data-logger" level="info" additivity="false">

answered Jun 10 '16 at 10:42

Mureinik

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I have added this already but still, get double logs? – Deepak Kumbhar Jun 07 '19 at 10:46
5

You can either add `additivity="false"`, as shown above. Or, you can remove the appender-ref elements from the "data-logger", since those are already inherited from the root logger. – Peter Tarlos Dec 13 '19 at 13:25

How to avoid double logging with logback?

1 Answers1