Spring boot does not load logback-spring.xml

Question

I have a sample Spring Boot application that uses Logback for logging. So I have logback-spring.xml next to the jar to configure the logging, however it does not work unless I specify it with logging.config, ex : logging.config=logback-spring.xml.

I have looked into Spring Boot ignoring logback-spring.xml where it suggests that it might be because there's already a spring.xml somewhere, but putting breakpoint on org.springframework.boot.logging.AbstractLoggingSystem.initializeWithConventions(LoggingInitializationContext, LogFile) shows that logFile is empty.

Am I doing something wrong here ?

Answer 1

By default, Spring will not look for resources outside the jar file. If you want to use an external logback configuration file, you must pass it's location when starting the jar:

$ java -jar -Dlogback.configurationFile=/full_path/logback.xml app.jar

Please, do not include the logback.xml into the final Jar file, it will cause multiple logback.xml files in the classpath.

Answer 2

As per the description of the problem, you are using the externalized version of your log configuration. The file is kept outside the jar. So you have to mention the path as run-time argument as below:

-Dlogging.config=file:logback-spring.xml

Or in mention the same property in application.properties as below:

logging.config=file:logback-spring.xml

The reason it pickup the file from resources folder, because it is configured in spring that way. Spring pick up the logback file by below names from classpath.

logback-spring.xml, logback-spring.groovy, logback.xml, or logback.groovy

Please check the relevant docs at spring-boot custom log configuration

Answer 3

Dockerfile:

COPY /rootProjectName/src/main/resources/logback-spring.xml /deployments/  

application-dev.properties:

logging.config=classpath:logback-spring.xml

I'm running a docker container and must copy over the resource folder into my deployments folder in my Docker File... but once copied over
this is the logging.config value that works for me (adding the classpath word)