This app demonstrate how to run a python app as a systemd daemon.
The app will run every 5 seconds. Its like running a cron every 5 seconds.
You can control the app with systemd commands
systemctl restart complex
systemctl start complex
systemctl stop complex
systemctl enable complex
Logs will go to /var/log/messages and will be managed by journalctl e.g journalctl -u complex -f to follow this app specific logs