[logback-dev] [JIRA] Updates for LOGBACK-1713: AppenderFactory not set in SiftingAppender

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logback / LOGBACK-1713 [Open]
AppenderFactory not set in SiftingAppender

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 Issue created
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Andree Wormuth created this issue on 13/Dec/22 2:19 PM
Summary:              AppenderFactory not set in SiftingAppender
Issue Type:           Bug
Affects Versions:     1.4.5
Assignee:             Logback dev list
Components:           logback-classic
Created:              13/Dec/22 2:19 PM
Environment:
  Classic Spring Web Application (no Spring Boot)
   Tomcat 9
   Java 17
Priority:             Major
Reporter:             Andree Wormuth
Description:
  We use the {{ch.qos.logback.classic.sift.SiftingAppender}} to create a separate log file for each of our imports. For that end we create a property {{importLogFile}} and put it into the {{MDC}}, the config looks as follows:
  {code:xml}
  <appender name="MyImport" class="ch.qos.logback.classic.sift.SiftingAppender">
  	<discriminator>
  		<key>importLogFile</key>
  		<defaultValue>undefined</defaultValue>
  	</discriminator>
  	<filter class="ch.qos.logback.core.filter.EvaluatorFilter">
  		<evaluator class="ch.qos.logback.classic.boolex.JaninoEventEvaluator">
  			<expression>
                  return mdc == null || mdc.get("importLogFile") == null;
              </expression>
  		</evaluator>
  		<OnMismatch>NEUTRAL</OnMismatch>
  		<OnMatch>DENY</OnMatch>
  	</filter>
  	<sift>
  		<appender name="FILE-${importLogFile}" class="ch.qos.logback.core.FileAppender">
  			<file>${importLogFile}</file>
  			<append>false</append>
  			<layout class="ch.qos.logback.classic.PatternLayout">
  				<pattern>%d %level %logger{35} - %msg%n</pattern>
  			</layout>
  		</appender>
  	</sift>
  </appender>
  {code}
  We followed the docs in that matter, see [here|https://logback.qos.ch/manual/appenders.html#SiftingAppender].
  
  This worked flawlessly while we were using logback *1.2.x*. With the update to version *1.3* though, the initialization process seems to have changed. We're trying to use the latest version (1.4.5 ({{ch.qos.logback:logback-classic:1.4.5}}), and now instead of separate log files we get following error message during startup of our web app:
  {noformat}
  Appender named [FILE-importLogFile_IS_UNDEFINED] not referenced. Skipping further processing.
  ERROR in ch.qos.logback.classic.sift.SiftingAppender[MyImport] - AppenderFactory has not been set. Aborting
  {noformat}
  I did not find a solution for this in the logback docs. There were changes concerning the usage of nested appenders (some other log messages indicate as much) but as far as I understand the {{SiftingAppender}} does not really fall under that category - and the docs mentioned above haven't been changed, so I guess that approach should still be valid.


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