Enter debug mode via USR1 signal

demo_server.rb

require 'servolux'
require 'logging'

# This is a simple demonstration server that shows how to register a signal handler
# for toggling the log level of your application. This is very useful in a production
# application where you want to enable debug messages for a brief period of time. The
# Servolux::Server class looks for a few special methods and registers them as signal
# handlers. Here, the "usr1" method will be called when the USR1 signal is sent to the
# process.
#
class DemoServer < Servolux::Server

  # Configure our demo server.
  #
  def initialize
    super( 'demo_server',
        :logger => Logging.logger[self],
        :interval => 30    # invoke the run method every 30 seconds
    )
  end

  # The main run loop will be called at a regular interval.
  #
  def run
    logger.debug 'Entering main run loop'

    # do some work here ...
  end

  # If SIGUSR1 is sent to the process, then the logging level is
  # toggled between the normal level and the debug level.
  #
  def usr1
    @__level ||= nil
    r = Logging.logger.root

    if @__level.nil?
      r.level, @__level = :debug, r.level
      logger.debug "Entering debug mode."
    else
      logger.debug "Exiting debug mode."
      r.level, @__level = @__level, nil
    end
  end

end