Gemfile

source 'https://rubygems.org'

gem "sd_notify"

restartering.rb

#!/usr/bin/env ruby

# A test application to experiment with sd_notify from a ruby process

require "sd_notify"

# On startup, let's wait for 10s to give us a chance to look at the state of things

sleep 10

SdNotify.ready

# If we're asked to reload, pretend we're working for 10s so we have a chance to
# look at things here too
Signal.trap("HUP") do
  SdNotify.reloading
  sleep 10
  SdNotify.ready
end

loop do
  sleep 0.3
end

restartering.service

[Unit]
Description=A unit to experiment with services and sd_notify

[Service]
Type=notify
WorkingDirectory=/home/carlos/restartering/
ExecStart=bundle exec ruby restartering.rb
ExecReload=/bin/kill -HUP $MAINPID