By default, Grails configuration information is stored in grails-app/config/Config.groovy and contains various settings, including the configuration for logging. While this is convenient, it has caused me concern when deploying applications since Config.groovy will get compiled and placed in the war file. True, you can have different settings based on the environment (development, production, etc.), but often I can not predict what the production environment might be. Perhaps I need to tweak the logger level in production after it has been deployed. Maybe the database needs to be moved to a different server.
External configuration files allow you to make these changes without having to redeploy the war file.
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