systemd user unit + timer example

instructions.md

Save these files as ~/.config/systemd/user/some-service-name.*

Run this now and after any modifications: systemctl --user daemon-reload

Try out the service (oneshot): systemctl --user start some-service-name

Check logs if something is wrong: journalctl -u --user-unit some-service-name

Start the timer after this user logs in: systemctl --user enable --now some-service-name.timer

some-service-name.service

[Unit]
Description=Do some thing
After=network.target

[Service]
Type=oneshot
ExecStart=/home/my-user-name/my-service/script.py --some-arg=some-value

[Install]
WantedBy=default.target

some-service-name.timer

[Unit]
Description=Run "Do some thing" every 30 minutes

[Timer]
OnBootSec=3min
OnUnitActiveSec=30min

[Install]
WantedBy=timers.target

You can prefix the executable path with the home directory variable, and your logs may fill with errors if you don't set a working directory, e.g.:

WorkingDirectory=%h
ExecStart=%h/my-service/script.py --some-arg=some-value

OnUnitInactiveSec= may be more suitable for some tasks, it means "time since service last finished".

https://wiki.archlinux.org/title/systemd/User#Automatic_start-up_of_systemd_user_instances:

The systemd user instance is started after the first login of a user and killed after the last session of the user is closed. Sometimes it may be useful to start it right after boot, and keep the systemd user instance running after the last session closes, for instance to have some user process running without any open session. Lingering is used to that effect. Use the following command to enable lingering for specific user:

loginctl enable-linger $username