strategy/periodic: support configuring a time zone for reboot windows #524

kelvinfan001 · 2021-04-09T23:56:30Z

Support configuring reboot windows defined by a user-specified time zone, instead of only UTC.

Include a single time_zone field (that defaults to UTC if not
specified) in the periodic strategy's configuration. Whenever we
need to check whether we're currently in an allowed reboot window,
we convert the current naive time to the naive time under the
specified time zone, and check whether we are currently in a reboot
window.

Under this implementation, we keep invariant clock time for reboots,
but do NOT keep invariant reboot window length; thus, in some cases,
reboot windows can be lengthened, shortened, or skipped entirely.

kelvinfan001 · 2021-04-10T00:02:53Z

The current implementation uses Option 3 from #301 (comment).
This is still a work in progress as we need to properly address the third bullet point in #301 (comment).

Edit: outdated.

src/strategy/mod.rs

src/config/fragments.rs

src/strategy/periodic.rs

kelvinfan001

I added some comments in places I feel like needs some extra attention :)

docs/usage/updates-strategy.md

lucab · 2021-04-14T10:16:18Z

src/strategy/mod.rs

-                p.human_remaining()
+                // If not using UTC, we cannot accurately calculate remaining time;
+                // display next window week day and time, instead.
+                if p.time_zone != tzfile::Tz::named("UTC").unwrap() {


I think it makes sense to place this into a p.is_calendar_utc() -> bool, caching the boolean upfront instead of re-computing it each time.

We now have a p.tz_name() that gets the "cached" name of the time zone. Using this over a boolean because we need to use this name in human_next_reboot_window() too.

src/strategy/mod.rs

src/strategy/periodic.rs

Include a single `time_zone` field (that defaults to UTC if not specified) in the `periodic` strategy's configuration. Whenever we need to check whether we're currently in an allowed reboot window, we convert the current naive time to the naive time under the specified time zone, and check whether we are currently in a reboot window. Under this implementation, we keep invariant clock time for reboots, but do NOT keep invariant reboot window length; thus, in some cases, reboot windows can be lengthened, shortened, or skipped entirely.

jlebon · 2021-04-29T13:08:34Z

Thanks, @kelvinfan001! Looking forward to using this on my FCOS server. :)

travier · 2021-04-29T13:16:10Z

Same here! Thanks!

kelvinfan001 added kind/enhancement status/on-hold area/usability labels Apr 9, 2021

kelvinfan001 commented Apr 10, 2021

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lucab reviewed Apr 12, 2021

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