Setting up the logger in rails 3
By default, Rails should be logging to an environment-specific log file in your project's log directory. It will be called either test.log, development.log, or production.log depending on which environment you're running in.
You can log directly to Rails' logger using the Rails.logger object:
Rails.logger.info "My info message"Rails.logger.debug "My debugging message"Rails.logger.warn "My warning message"Rails used to use Ruby's standard logging class, but it now uses ActiveSupport::BufferedLogger. (The official Ruby on Rails Guides are incorrect when they say "Rails makes use of Ruby’s standard logger to write log information").