From: Phillip Wood <phillip.wood123@gmail.com>
Date: Wed, 09 Aug 2023 10:03:15 GMT
Subject: Re: [PATCH 6/6] maintenance: use random minute in systemd scheduler
Message-ID: <44b7c1d7-83f3-c549-aa5f-2f06276ba599@gmail.com>
In-Reply-To: <5bb4313a-01f3-4dea-b724-fb41a8def334@github.com>

On 08/08/2023 18:24, Derrick Stolee wrote:
> On 8/8/2023 9:56 AM, Derrick Stolee wrote:
>> On 8/8/2023 5:53 AM, Phillip Wood wrote:> Hi Stolee
> 
>>> 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

>>> 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