Mule esb: is "rolling" log files a default behavior? - mule

Question

I have mule 3.8.1. I can see logs for each app I have in %MULE_BASE%/logs/%MULE_APP%.log just like defined in wrapper.conf file. Example log files I have are:
mule-app-APP1.log.2020-04-07
mule-app-APP1.log
mule-app-APP2.log.2020-04-07
mule-app-APP2.log
I understand that by default logs are created in the format %MULE_APP%.log where MULE_APP is mule-app-<app_name>.
My question is about "rolling" files. I mean, creating a new log file each day. There is log4j2.xml in the project but there is only AsyncRoot appender pointing out to Console appender. My question: is the "rolling" log files behavior default in mule ? or there must be a configuration set in the project by someone else, that I'm missing ?

Answer 1

This is not Mule behaviour. This is log4j2 behaviour which is defined in the log4j2.xml file. If you have definition like this
<RollingFile name="file" fileName="${sys:mule.home}${sys:file.separator}logs${sys:file.separator}myApp.log"
filePattern="${sys:mule.home}${sys:file.separator}logs${sys:file.separator}myApp-%i.log">
<PatternLayout pattern="%-5p %d [%t] [event: %X{correlationId}] %c: %m%n" />
<SizeBasedTriggeringPolicy size="10 MB" />
<DefaultRolloverStrategy max="10"/>
</RollingFile>
which is generate automatically when you create myApp mule Application then you will alwyas have only 10 latest rolling logs.
If you elimate fileName like this
<RollingFile name="file"
filePattern="${sys:mule.home}${sys:file.separator}logs${sys:file.separator}myApp-%i.log">
<PatternLayout pattern="%-5p %d [%t] [event: %X{correlationId}] %c: %m%n" />
<SizeBasedTriggeringPolicy size="10 MB" />
<DefaultRolloverStrategy max="10"/>
</RollingFile>
then you will have behaviour like you described with infinite rolling logs.
See more about this here https://simpleflatservice.com/mule4/RollingLogFiles.html