Does SiftingAppender have retention policy?

[ruanwenjun]

Hi team,

My use case is I need to create a separate log file for different task, the task will be created automically, so the task number will increase with time.

I use SiftingAppender to do this.

<appender name="TASKLOGFILE" class="ch.qos.logback.classic.sift.SiftingAppender">
        <Discriminator class="TaskLogDiscriminator">
            <key>taskId</key>
            <logBase>${log.base}</logBase>
        </Discriminator>
        <sift>
            <appender name="FILE-${taskId}" class="ch.qos.logback.core.FileAppender">
                <file>logs/${taskId}.log</file>
                <append>true</append>
            </appender>
        </sift>
    </appender>

We want to set the max number of logs, just like the maxHistory strategy in SizeAndTimeBasedRollingPolicy.
Is this possible? I search some doc, the SizeAndTimeBasedRollingPolicy can only use in RollingFileAppender. I try to use RollingFileAppender to replace the FileAppender, but it seems not work.

[ceki]

@ruanwenjun In SiftingAppenderBase, an instance of AppenderTracker builds new appenders and keeps track of them. It removes stale appenders. I suggest that you look at adapting AppenderTracker for your use case. Let us know if you need further clarifications.

[ruanwenjun]

@ceki Thanks for your quickly reply. You mean the AppenderTracker will dynamic create the new appenders and manage the appender's lifecycle, once the appender is stale, e.g receive FINALIZE_SESSION_MARKER event, then the AppenderTracker will use endOfLife method to remove it from memory.

So I can implement the AppenderTracker to clean the log file from system once the appender is removed?

Maybe I didn't make myself clear, once the appender is close, the log file might still need to put at system. I only want the logback can clear the log files when they reach a certain size or number. I'm not sure if this goes against logback's design principles.

[ceki]

So I can implement the AppenderTracker to clean the log file from system once the appender is removed?

AppenderTracker has access to a significant amount of information which it could leverage in order to compute the log files that need to be removed.

[ruanwenjun]

So I can implement the AppenderTracker to clean the log file from system once the appender is removed?

AppenderTracker has access to a significant amount of information which it could leverage in order to compute the log files that need to be removed.

OK, I will take a try, thanks.