I'm using log4j 2.0-beta8 in a webapp, and running it under Tomcat.
I'm setting a system property in my apps ServletContextListener, and using that system property in my log4j2.xml file, like so:
<appender type="FastFile" name="File" fileName="${sys:catalina.home}/logs/${sys:application-name}.log">
On my Windows machine, a log file named "${sys." (always 0 bytes) is being created instead of a log file with the application-name. The same war deployed on one of our linux servers (also tomcat 7, though a slightly different version) does not create a ${sys." file and instead creates a log file with the intended application-name.
What I think must be happening is that my app's ServletContextListener contextInitialized method is getting called before Log4jServletContextListener's on the server, but that they are getting called in the opposite order on my local machine. The javadoc seems to suggest that the intention is for it Log4jServletContextListener's to always occur first. This raises several issues:
1) Is the fact that they get called in different orders on different machines a failure of Tomcat to call them in the right order? Or a failure of the log4j code to ensure things are set up so as to guarantee this order? Or is the order even specified and guarranteeable?
2) Is Log4jServletContextListener's contextInitialized being called first necessarily desirable? If Log4jServletContextListener always gets called before the application's context listener, how is the application to set up variables for use in the log4j configuration, particularly, for example (which is what I am doing), to get the webapp's name from the servlet context path to name the log files? Is there some better way to do this? (Ideally without requiring configuration to be loaded twice...which is what I ended up happening with logback when I tried to set it up to do this same thing.)
According to the servlet spec "The Web container registers the listener instances according to the interfaces they implement and the order in which they appear in the deployment descriptor. During Web application execution, listeners are invoked in the order of their registration." Since Log4jServletContextListener doesn't appear in the web.xml, I assume it should call them "according to the interfaces they implement". I have no idea what that is supposed to mean, though.
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