Grails - Logging from a Controller or Service

Logging informational messages from a controller or service is the sort of thing I wish I'd figured out how to do when I first started playing around with Grails. All the information is in the docs, but it took me a while to find it and it could be a bit obscure for someone just getting started.

Here's all you have to do:

1. Open Config.groovy and find the log4j block.
2. At the bottom, add a line like this:

info 'grails.app'

3. In your controller action, wherever you want to log something, just add a line something like this:

log.info "In myController, my Action myVar is: ${myVar}"

Reference Link：
http://dowdrake.com/showthread.php?86-Grails-Logging-from-a-Controller-or-Service