External Log4J2 configuration in Java EE application
I’m working on a Java EE project which had configuration files in resources folder. The web project is assembled into a war file using Maven and deployed to Tomcat.
Then I started doing some maintainance and tried to externalize the configurations which had been successful to some extent.
In case you wonder how it was on production before I edited the code, here it goes:
// x stands for `application.conf` or `en.properties` depending on where in the code the file is being getClass().getClassLoader().getResourceAsStream(x) I’ve moved every single file under resources to /CATALINA_BASE/conf/myProject and I’m reading from these paths in the code. (doesn’t look like a good practice to me)
And here is my version:
// x stands for `application.conf` or `en.properties` depending on where in the code the file is being read new File(System.getProperty("catalina.base") + "/conf/myProject/x") This works fine obviously but the project also has a log4j2.properties file which was automatically read from the classpath before and since I’ve externalized the configuration I’m not able to read from it.
What I tried was setting a parameter inside web.xml like below(not sure if it is right thing to do)
<web-app> ... <context-param> <!-- also tried with log4jConfigLocation--> <param-name>log4Configuration</param-name> <param-value>file:${catalina.base}/conf/myProject/log42.properties</param-value> </context-param> ... </web-app> The error output during application startup:
ERROR StatusLogger No log4j2 configuration file found. Using default configuration: logging only errors to the console. Set system property ‘org.apache.logging.log4j.simplelog.StatusLogger.level’ to TRACE to show Log4j2 internal initialization logging.
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
Any suggestions would be appreciated.
UPDATE: The tomcat running on the server is serving several other applications so setting VM arguments is not an option for me since other projects might have their log4j configurations in their classpath and VM arguments may break those configurations.
You should go to Catalina.properties and add the conf/myProject directory to the classpath. Then your could can just look for files at the root of the classpath. You can create a logging configuration for each web app in that directory by changing your configuration in web.xml to just the name of the file – i.e. log4j2-appname.xml.
Another alternative that could work is to change your file url from file: to file://.
BTW – my employer has apps running like this – multiple apps in a single tomcat. It has caused all kinds of problems over time and really is a bad idea.
