Relocate

The io.smallrye.config.RelocateConfigSourceInterceptor allows to relocate a configuration name to another name, by providing a transformation function or just a simple key value map.

When a configuration key is renamed, lookup needs to happen on the new name, but also on the old name if the config sources are not updated yet. The relocation function gives priority to the new resolved configuration name or resolves to the old name if no value is found under the new relocation name.

package org.acme.config;

import java.util.function.Function;
import io.smallrye.config.RelocateConfigSourceInterceptor;

public class MicroProfileConfigRelocateInterceptor extends RelocateConfigSourceInterceptor {
    public MicroProfileConfigRelocateInterceptor(final Function<String, String> mapping) {
        super(name -> name.startsWith("mp.config") ?
                      name.replaceAll("mp\\.config", "smallrye.config") :
                      name);
    }
}

And registration in:

META-INF/services/io.smallrye.config.ConfigSourceInterceptor

org.acme.config.MicroProfileConfigRelocateInterceptor

The MicroProfileConfigRelocateInterceptor can relocate configuration names in the mp.config namespace to the smallrye.config namespace.

Example

application.properties

mp.config.profile=test
smallrye.config.profile=prod

A lookup to mp.config.profile returns the value prod. The config finds a valid value in the relocated name smallrye.config.profile, so the interceptor will use this value instead of the one in mp.config.profile.