Demo ruby script. Catching signals and simulate unexpected failure

signals.rb

# frozen_string_literal: true

seconds       = 0.0
STEP          = 0.5
OUTPUTFILE    = "/home/denis/code/mad/signals/o.log"
BAD_FILE      = "/home/denis/code/mad/signals/bad.txt"

def say(message)
  File.open(OUTPUTFILE, 'a') { |file| file.puts message }
end

def detect_bad_file
  if File.exist? BAD_FILE
    say("Detected bad file")
    File.delete(BAD_FILE)
    raise
  end
end

say("")
say("Welcome!")
say("")

at_exit do
  say("Closing with #{$!} ...")
  sleep STEP
end

Signal.trap("INT") { exit }

loop do
  detect_bad_file
  say "Seconds: #{seconds += STEP}"
  sleep STEP
end