Re: [Task Scheduler] Repeating alarms

How is that situation currently handled for one-shot alarms?

/m



On Mon, Nov 18, 2013 at 10:07 AM, Kenneth Rohde Christiansen <
kenneth.christiansen@gmail.com> wrote:

> I am OK with recurring alarms, but what is supposed to happen if the
> device is off and an alarm cannot be met?
>
> Kenneth
>
>
> On Wed, Nov 13, 2013 at 1:38 PM, John Mellor <johnme@google.com> wrote:
>
>> I notice that the API only allows one-shot alarms (setTimeout style), so
>> apps that want to run periodically (both at exact times like a recurring
>> alarm/calendar event, and inexact times like background syncing) must
>> schedule a new task every time their task gets started.
>>
>> That helps to keep the API nice and simple, but I worry that it might
>> cause sporadic failures. Specifically, if the app crashes, gets killed, or
>> hits an exception, in between the task starting and the app scheduling its
>> next execution, it will never be run again (until the app is next manually
>> launched, at which point a well-written app might check that the task is
>> still scheduled, though many apps may neglect to do this).
>>
>> Two possible solutions:
>>
>> 1. Automatically schedule an additional task if a task crashes or gets
>> killed. However, there's a risk that this would perform actions twice (e.g.
>> if the background task sends an email, and we run an additional task with
>> the same data, 2 emails might get sent); alternatively we could pass null
>> data, but then that might confuse an app that only every schedules itself
>> with data. So I'm not really sure this is workable.
>>
>> 2. Add a recurring alarm variant. It might make sense to only allow inexact
>> alarms<http://lists.w3.org/Archives/Public/public-sysapps/2013Nov/0019.html> to
>> automatically recur; this would also allow us to simplify the API, as with
>> inexact alarms you don't actually need to specify an interval, instead the
>> browser will heuristically determine how often you deserve to get run (or
>> we could allow providing a "minimum interval", which is the period of time
>> after a given task execution during which the task should *not* be run, and
>> after that the browser can schedule the task whenever).
>>
>> What do people think?
>> Thanks,
>> John
>>
>
>
>
> --
> Kenneth Rohde Christiansen
> Web Platform Architect, Intel Corporation.
> Phone  +45 4294 9458 ﹆﹆﹆
>