How can I configure system properties or logback configuration variables from typesafe config?

Question

I have variables with defaults in my logback.xml configuration file, and I would like to be able to optionally set these variables from my typesafe config app

Answer 1

You can use the PropertyDefiner interface that logback provides. Non trivial scaffolding but allows you to configure using XML instead of within your application. E.g.:

package com.myapp;

import ch.qos.logback.core.PropertyDefinerBase;
import com.typesafe.config.ConfigFactory;

public class TypesafeConfigPropertyDefiner extends PropertyDefinerBase {

    private String propertyName;

    @Override
    public String getPropertyValue() {
        return ConfigFactory.load().getString( propertyName );
    }

    public void setPropertyName( String propertyName ) {
        this.propertyName = propertyName;
    }
}

Then, in your logback.xml file:

    
        myapp.logging.loglevel
    
    
       ...
    

Now, the above logback.xml file will read myapp.logging.loglevel from your typesafe config file (e.g. application.conf).