log4j root logger overwritten by log4j.properties in spring-boot jar

[tkruse]

Hi,

we have our log4j configuration in a file called log4j-custom.properties. We load this on embedded tomcat startup using -Dlog4j.configuration=log4j-custom.properties.
This has the effect that those properties will be loaded first on startup. However, startup then continues to find log4j.properties and basic-log4j.properties in the spring-boot jar, which set the log4j.rootCategory (should be rootLogger by now I believe), meaning also our Appenders get closed.

I have no clear suggestion of how to prevent this right now, nor do I know whether this is a bug or not, but it took us by surprise.

[tkruse]

What we were trying to achieve was to define different log4j-xyz.properties to be loaded depending on the Spring profile / on our deployment chain (DEV, STAGE, PROD). We could init loggers programmatically once we had a Spring context, but that is a bit late (some early log messages would be lost), so we thought we might as well use the -Dlog4j.configuration=... vm option to get the configuration we need in each environment.

Also, independently it would be nice if we could change the logging configuration for a deployed war (at the cost of restarting tomcat with a different configuration file. This could also be achieved by programmatically loading the file configured with log4j.configuration in the application (meaning the configuration would be loaded twice).

[snicoll]

Can you try -Dlogging.config=classpath:log4j-custom.properties ?

[tkruse]

Thanks, that seems to work like a charm.

For posteriority: That setting seems to prevent any further log4j.properties from being loaded.

[posto]

@snicoll : your suggestion works only if there is no log4j.properties file in the classpath.
If there is one, log4j will read it first, then read the basic-log4j.properties from spring and only as a last step -- the log4j-custom.properties specified in -Dlogging.config.

My use-case is to use log4j-dev.properties for my dev work (passing -D from intellij) and log4j.properties for production (missing -D, so default behaviour applies).

Is spring forcing the loading of basic-log4j.properties or how does this happen? Long shot: I also have the environment=dev property in my app, maybe this is somehow clashing with spring boot?