Can spring-boot application.properties file woking with log4j2.xml configuration?

Question

I want to define high-level file logging in application.properties as a convenience to leverage my log4j2.xml file configuration. By itself my log4j2 config is working fine, however I was hoping to control logging levels and log file and path info from the application.properties file. I have the spring-boot-starter-log4j2 dependency in the application's pom file.

In log4j2.xml I have as one of the properties

<Property name="LOG_FILE">${LOG-DIR}/test.log</Property>

, where LOG-DIR is defined in another (previous) property in the same file. In my application.properties file, I have

logging.file=LOG_FILE 

as a property, plus several level properties such as

logging.level.org.springframework.web=DEBUG

none of these log-related properties as defined in my application.properties file are working to build the corresponding log file. Again, when I simply use log4j2.xml by itself it works fine, but wanted to take advantage of the convenience of application.properties for logging configuration.

Any insights into what I am doing wrong are greatly appreciated. thank you

Answer 1

If I understood your question right, you are looking at Property Substitution feature of log4j2.

You can define logging property in application.properties file like below:

log.file.path=/myDir/logpath 

And then the property(s) lookup defined as Property in log4j2.xml:

<Configuration>  
  <Properties>  
      <property name="LOG_FILE">${bundle:application:log.file.path}</property> 
  </Properties>  

Now all the property can be referred in same log4j2.xml with ${propertyName} notation, which eventually points to values from application.properties file.