Re: [PATCH 6/6] maintenance: use random minute in systemd scheduler

On 08/08/2023 18:24, Derrick Stolee wrote:

On 8/8/2023 9:56 AM, Derrick Stolee wrote:

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On 8/8/2023 5:53 AM, Phillip Wood wrote:> Hi Stolee

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So only one of these jobs will succeed. The cron entries are careful to
only run one job at a time, I think it would be worth doing the same
thing here. I think the using the following format strings would fix this.

Hourly: "Tue..Sun *-*-* 1..23:00:%02d"
Daily:  "Tue..Sun *-*-* 00:00:%02d"
Weekly: "Mon      *-*-* 00:00:%02d"

I would modify this with dropping the "Tue..Sun" from the hourly schedule,
as we still want 23 runs on Mondays.

Oops, well spotted

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It looks like the launchctl schedule has the same issue.

I will take a look at this and consider some additional patches to correct
these issues across both schedulers. Thank you for the attention to detail!

Taking a look, it seems that launchctl does not have this same problem.

The schedule is set via an <array> of <dict>s as follows:

	case SCHEDULE_HOURLY:
		repeat = "<dict>\n"
			 "<key>Hour</key><integer>%d</integer>\n"
			 "<key>Minute</key><integer>%d</integer>\n"
			 "</dict>\n";
		for (i = 1; i <= 23; i++)
			strbuf_addf(&plist, repeat, i, minute);
		break;

	case SCHEDULE_DAILY:
		repeat = "<dict>\n"
			 "<key>Day</key><integer>%d</integer>\n"
			 "<key>Hour</key><integer>0</integer>\n"
			 "<key>Minute</key><integer>%d</integer>\n"
			 "</dict>\n";
		for (i = 1; i <= 6; i++)
			strbuf_addf(&plist, repeat, i, minute);
		break;

This means that we create an hourly schedule for each hour 1..23
(no 0th hour means no collision with daily or weekly schedule) and
a daily schedule for each day 1..6 (no 0th day means no collision
with the weekly schedule).

Does this match your understanding?

Yes, having read it again - sorry I'd misunderstood it yesterday.

The overlap _definitely_ exists in systemd, which I will fix.

That's great

Best Wishes

Phillip