Logback: Rollover is not deleting expired Logs - logback

Question

I have a RollingFileAppender which is archiving the logs to files like this:
/data/work/logs/printPDF/logs/service/printPDF_2020-01/printPDF_2020-01-23_0.log.gz
Unfortunately, it is not deleting old archives (like the one named above).
Does anybody know what I'm doing wrong?
Below is an excerpt from the Startup Logback Console output:
- setting totalSizeCap to 20 GB
- Archive files will be limited to [100 MB] each.
- Will use gz compression
- Will use the pattern /data/work/logs/printPDF/logs/service/printPDF_%d{yyyy-MM, aux}/printPDF_%d{yyyy-MM-dd}_%i.log for the active file
- The date pattern is 'yyyy-MM-dd' from file name pattern '/data/work/logs/printPDF/logs/service/printPDF_%d{yyyy-MM, aux}/printPDF_%d{yyyy-MM-dd}_%i.log.gz'.
- Roll-over at midnight.
- Setting initial period to Tue Nov 10 05:31:17 MET 2020
- Cleaning on start up
- Assuming default type [ch.qos.logback.classic.encoder.PatternLayoutEncoder] for [encoder] property
- first clean up after appender initialization
- Multiple periods, i.e. 32 periods, seem to have elapsed. This is expected at application start.
- Active log file name: /data/work/logs/printPDF/printPDF.log
- File property is set to [/data/work/logs/printPDF/printPDF.log]
As you can see from the Console Output, it has recognised a Daily Date Pattern & expects to rollover at midnight.
It is rolling over at midnight, but expired Logs are not being deleted. Here are a few of the filenames it failed to delete:
/data/work/logs/printPDF/logs/service/printPDF_2020-01/printPDF_2020-01-23_0.log.gz
/data/work/logs/printPDF/logs/service/printPDF_2020-01/printPDF_2020-01-23_1.log.gz
/data/work/logs/printPDF/logs/service/printPDF_2020-02/printPDF_2020-02-28_0.log.gz
And here's the one it just created at midnight:
/data/work/logs/printPDF/logs/service/printPDF_2020-11/printPDF_2020-11-10_0.log.gz
Here's logback.xml, which I expect to retain 90 days:
<configuration debug="true">
<property name="SERVICE" value="printPDF" />
<property name="LOGDIR" value="/data/work/logs/${SERVICE}" />
<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
<encoder>
<pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
</encoder>
</appender>
<appender name="RollingFile" class="ch.qos.logback.core.rolling.RollingFileAppender">
<file>${LOGDIR}/${SERVICE}.log</file>
<append>true</append>
<rollingPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedRollingPolicy">
<FileNamePattern>${LOGDIR}/logs/service/${SERVICE}_%d{yyyy-MM, aux}/${SERVICE}_%d{yyyy-MM-dd}_%i.log.gz</FileNamePattern>
<maxHistory>90</maxHistory>
<maxFileSize>100MB</maxFileSize>
<totalSizeCap>20GB</totalSizeCap>
<cleanHistoryOnStart>true</cleanHistoryOnStart>
</rollingPolicy>
<encoder>
<Pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</Pattern>
</encoder>
</appender>
<logger name="org.apache" level="ERROR"/>
<logger name="ch.qos.logback" level="INFO"/>
<root level="INFO">
<appender-ref ref="STDOUT"/>
<appender-ref ref="RollingFile"/>
</root>
</configuration>

Answer 1

you are using monthly rollover: "%d{yyyy-MM}" so maxhistory=3 will keep three months of logs.