Separate logging using LOG4J2 - log4j2

Question

I have a requirement to maintain separate logging files EAR1.log and EAR2.log for 2 Java EE applications EAR1 and EAR2 respectively using LOG4J2 v2.1. Going through the internet, I could see help specific to LOG4J v1.x, but couldn’t find any for LOG4J2.
EAR1 (need to use “EAR1-log4j2.xml”):
1. Web project “web1”
2. EJB project “ejb1”
3. Java project “java1”
4. Java project “java2”
5. Java project “java3”
EAR2 (need to use “EAR2-log4j2.xml”):
1. Web project “web2”
2. EJB project “ejb2”
3. Java project “java1” (same as above)
4. Java project “java2” (same as above)
5. Java project “java3” (same as above)
http://logging.apache.org/log4j/2.x/manual/migration.html
http://logging.apache.org/log4j/2.x/manual/logsep.html
what is working now:
my log4j2.xml is placed in ApplicationServer classpath & a single log is successfully getting written for both the EAR’s
my completed attempts to maintain separate log files for both EAR’s:
• Modifying web.xml only applies the logging change to the web project alone
• I tried the following code, but this applies only to current class
LoggerContext loggerCtx = Configurator.initialize("mrpst", null, PathOfMyLog4j2XmlPath );
Logger log = loggerCtx.getLogger("MyClassName");
I’m trying to check if it is possible to complete this requirement by editing log4j2.xml alone(without code change). Appreciate if a documentation link can be provided or any alternate approach.

Answer 1

My suggestion is to inject context into your log event and filter on that context using a logger route, which directs to an appropriate appender.
At the point of logging:
String routeKey = SOME_FIELD_THAT_IDENTIFIES_CONTAINER;
ThreadContext.put( "myEARroute", routeKey );
In your log4j2.xml config:
<Routing name="myEARroute">
<Routes pattern="$${ctx:myEARroute}">
<!-- if you forget to inject context, the routing key will be empty -->
<Route
key="$${ctx:myEARroute}"
ref="STDOUT" />
<Route
key="EAR1"
ref="myEAR1Appender" />
<Route
key="EAR2"
ref="myEAR2Appender" />
</Routes>
</Routing>
Now you just have to create appenders matching your appender names:
<RollingRandomAccessFile
name="myEAR1Appender"
filename="logs/Ear1.log"
<!-- fill in the rest of your appender config, as desired -->
</RollingRandomAccessFile>
repeat for other appenders.