at_exit.rb

def operation(iteration)
  # ... Implemented As above
end

# Only runs if the file is the entry point for execution,
# but not if loaded as a library
if $0 == __FILE__
  puts "[INFO #{Time.now}] #--- Starting Worker Program ---#"

  at_exit do
    puts "[WARN #{Time.now}] #--- Received interrupt ---#"

    # But now what?!
  end

  iteration = 0

  # Main loop
  while true
    operation(iteration)
    iteration += 1
  end
end