Apache karaf4.2.3 - separate log file for each bundle - log4j2

Question

How to create a separate log file for each bundle deployed in karaf-4.2.3 using pax logging, which has log4j2 native style config?
I've tried with routing appender, but no results.
I am excepted to write each bundle logs in a separate log file for easy debugging.

Answer 1

I don't know anyway doing this automatically. But what you could do is to create for each module a separate configuration based on the root package name
log4j2.logger.xy.name = com.company.module.xy
log4j2.logger.xy.level = INFO
log4j2.logger.xy.additivity = false
log4j2.logger.xy.appenderRef.inovel.ref = XyFile
log4j2.logger.zz.name = com.company.module.zz
log4j2.logger.zz.level = INFO
log4j2.logger.zz.additivity = false
log4j2.logger.zz.appenderRef.inovel.ref = ZzFile
log4j2.logger.keycloak.name = org.keycloak
log4j2.logger.keycloak.level = INFO
log4j2.logger.keycloak.additivity = false
log4j2.logger.keycloak.appenderRef.keycloak.ref = KeycloakFile
And a ref could look like
# keyclok file appender
log4j2.appender.keycloak.type = RollingRandomAccessFile
log4j2.appender.keycloak.name = KeycloakFile
log4j2.appender.keycloak.fileName = ${karaf.data}/log/keycloak.log
log4j2.appender.keycloak.filePattern = ${karaf.data}/log/keycloak.log.%i
log4j2.appender.keycloak.append = true
log4j2.appender.keycloak.layout.type = PatternLayout
log4j2.appender.keycloak.layout.pattern = %d{ISO8601}
log4j2.appender.keycloak.policies.type = Policies
log4j2.appender.keycloak.policies.size.type = SizeBasedTriggeringPolicy
log4j2.appender.keycloak.policies.size.size = 8MB
log4j2.appender.keycloak.strategy.type = DefaultRolloverStrategy
log4j2.appender.keycloak.strategy.max = 10
This is a lot of manual work. So maybe someone come up with an automatic configuration
Sincerely

Answer 2

Just have a look at the official Log4j 2.x configuration coming with every Karaf distribution and have a look at the commented "Routing" section.
E.g. I've used the following in one of my projects:
# Root logger
log4j2.rootLogger.level = INFO
log4j2.rootLogger.appenderRef.RollingFile.ref = RollingFile
log4j2.rootLogger.appenderRef.RollingFile.filter.threshold.type = ThresholdFilter
log4j2.rootLogger.appenderRef.RollingFile.filter.threshold.level = WARN
log4j2.rootLogger.appenderRef.PaxOsgi.ref = PaxOsgi
log4j2.rootLogger.appenderRef.Console.ref = Console
log4j2.rootLogger.appenderRef.Console.filter.threshold.type = ThresholdFilter
log4j2.rootLogger.appenderRef.Console.filter.threshold.level = ${karaf.log.console:-OFF}
# Enable log routing...
log4j2.rootLogger.appenderRef.Routing.ref = Routing
# Loggers configuration
...
# Configure the routing (pay close attention to the escapes)...
log4j2.appender.routing.type = Routing
log4j2.appender.routing.name = Routing
log4j2.appender.routing.routes.type = Routes
log4j2.appender.routing.routes.pattern = \$\$\\\{ctx:bundle.name\}
log4j2.appender.routing.routes.bundle.type = Route
log4j2.appender.routing.routes.bundle.appender.type = RollingRandomAccessFile
log4j2.appender.routing.routes.bundle.appender.name = Bundle-\$\\\{ctx:bundle.name\}
log4j2.appender.routing.routes.bundle.appender.fileName = ${karaf.data}/log/bundle-\$\\\{ctx:bundle.name\}.log
log4j2.appender.routing.routes.bundle.appender.filePattern = ${karaf.data}/log/bundle-\$\\\{ctx:bundle.name\}.log.%d{yyyy-MM-dd}
log4j2.appender.routing.routes.bundle.appender.append = true
log4j2.appender.routing.routes.bundle.appender.layout.type = PatternLayout
log4j2.appender.routing.routes.bundle.appender.layout.pattern = ${log4j2.pattern}
log4j2.appender.routing.routes.bundle.appender.policies.type = Policies
log4j2.appender.routing.routes.bundle.appender.policies.time.type = TimeBasedTriggeringPolicy
log4j2.appender.routing.routes.bundle.appender.strategy.type = DefaultRolloverStrategy
log4j2.appender.routing.routes.bundle.appender.strategy.max = 31
That clearly worked for me. I wouldn't even think about a static configuration in OSGi! ;-)

Answer 3

log4j Configuration commented section on below link
https://github.com/apache/karaf/blob/master/assemblies/features/base/src/main/resources/resources/etc/org.ops4j.pax.logging.cfg
will log messages for each bundle to a separate file but By default karaf comes with multiple bundles this will result one log file for each bundle. So many logs file will be generated.
How it can be done for specific bundles which user have deployed on deploy folder