sysutils/nut: add support for timed shutdown with upssched

[Starkstromkonsument]

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Is your feature request related to a problem? Please describe.

1. I don't feel comfortable waiting to shutdown my devices until the battery of the UPS is low, because it leaves me without a properly working UPS when multiple outages occur before the batteries are charged again.
2. My setup is too complex to wait for LB / FSD to be triggered on the master for all clients at the same time, because the clients need to power down in a certain order. I achieve this by configuring upssched on the clients accordingly.
3. If I configure upssched on the clients to trigger a timed shutdown, I need to make sure the UPS is shutdown even if the power comes back before LB is reached, to assure everything comes back up automatically again (having 'ondelay' and 'offdelay' configured properly for the UPS and 'restore power on AC return' for the clients).

Describe the solution you'd like

• Add NOTIFYFLAG [...] EXEC lines for ONLINE, ONBATT to upsmon.conf
• Add a template for upssched.conf including a shutdown timer
• Add a template for /usr/local/bin/upssched-cmd accordingly
• Add config options for the shutdown timer to the WebUI ('enabled' and 'delay in seconds')

Describe alternatives you've considered Configure it via CLI (does not survive updates).

Additional context NUT Configuration Examples by Roger Price

I've got this running with a Raspberry Pi as master and I'll be happy to help working on a PR for OPNsense if it has a chance to get merged.

[pwatk]

+1

The only reason I use net client instead of standalone on OPNsense is the lack of a timed shutdown option in the UI.

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