By default, Grails excludes the logback.groovy file (among others) when plugins are assembled into JAR files, and for good reason. A plugin should not include the logger configuration, since the plugin would unexpectedly influence the configuration of the applications that include it.

I had a use case where I actually wanted this behavior, however. At my work, we write small applications that roughly provide a feature. They're not quite microservices, but they're not monolithic either. Since we write so many applications, we want to ensure that, as much as they can, they behave similarly. I needed to add a standard logger configuration to our standard library, but found that the logback.groovy file was excluded from the build.

To include the Logback configuration in a plugin build, simply add the following to your build.gradle file:

jar {
    getExcludes().remove('logback.groovy')
}