systemd timer

Use

[Timer]
OnBootSec=5min
OnUnitActiveSec=1h
Persistent=true

What It Does

A systemd timer starts a matching service on a schedule. In this course, the timer and service are user units under ~/.config/systemd/user.

Minimal Pair

site-build.service does the work:

[Service]
Type=oneshot
WorkingDirectory=%h/src
ExecStart=/usr/local/bin/npm run build

site-build.timer schedules it:

[Timer]
OnBootSec=5min
OnUnitActiveSec=1h
Persistent=true

Lifecycle

systemctl --user daemon-reload
systemctl --user enable --now site-build.timer
systemctl --user list-timers
systemctl --user start site-build.service
journalctl --user -u site-build.service --no-pager -n 50

Watch Out

Timers trigger services. Debug the service first, then debug the schedule.

Docs Pointers

• Run man systemd.timer.
• Read systemd timer units.
• Read automation timers, systemd user services, systemctl, and journalctl.