is there a way to use fixed-length index in logback's rolling filename pattern?

Question

is there a way to use fixed-length index in logback's rolling filename pattern? I mean rolled log-files will be indexed like:

application-2021-07-14_01.log.gz
application-2021-07-14_02.log.gz
application-2021-07-14_03.log.gz
...
application-2021-07-14_10.log.gz
application-2021-07-14_11.log.gz
...

instead of:

application-2021-07-14_1.log.gz
application-2021-07-14_2.log.gz
application-2021-07-14_3.log.gz
...
application-2021-07-14_10.log.gz
application-2021-07-14_11.log.gz
...

Answer 1

Try the fileNamePattern like this:

// left justified, missing zeroes
<fileNamePattern>logFile.%d{yyyy-MM-dd}_%-2i.log</fileNamePattern>
// zero left-pad with 2 places
<fileNamePattern>logFile.%d{yyyy-MM-dd}_%02i.log</fileNamePattern>

or

<fileNamePattern>logFile.%d{yyyy-MM-dd}_%i{2}.log</fileNamePattern>

As mentinoned in the docs but spreading it with the percent/formatter syntax.