Monitor a Rancher service and display popup toast notification when that service changes state

monitor_rancher.rb

#!/usr/local/bin/ruby -w

# Usage:
#   ./rancher_status.rb service_name

SERVICE = ARGV[0]

def notify(text)
  title = "Rancher"
  %x(osascript -e 'display notification "#{SERVICE} is #{text}" with title "#{title}"')
end

old_status = ""

while true do
  status = %x(rancher ps | grep #{SERVICE}).split[4]

  next unless status != old_status

  notify(status)
  old_status = status
end