[Freeipa-devel] [SSSD] Proposed changes to the HBAC grammar

[Dmitri Pal]

Stephen Gallagher wrote:
> On 11/22/2010 12:22 PM, Dmitri Pal wrote
> >> septet-of-the-month = interval 1-5
> > The septet is not used any more and should be removed, right?
>
> Yeah, I missed removing that. I've deleted it from the page now.
>
> >> day-of-the-month-interval = interval day-of-the-month
> > This should be a plain interval from 1-31 with no negatives since it
> is used in the M-day rule
> > I would argue that M-day can be just replaced with
>
> > M-day = "day" WSP interval 1-31
>
>
> I disagree. With this construction, we can say:
>
> accessTime = periodic monthly day -1 at 0900 + 000800
>
> (Read: on the last day of the month from 09:00 to 17:00)
>
> This would be useful for e.g. a regularly-scheduled backup task.
>

I think negative numbers are confusing and it is hard to decipher.
Why we cant say "last"? it will be much cleaner.

> > Keep in mind that definition of the interval here is as described
> below:
> > interval XX-YY = a comma-separated list of items from XX to YY, or
> dash-separated ranges.
> > For example, (interval 1-31) 3-7,10,12,15,25-31 with no spaces inside.
>
> > So definition of the day-of-the-month-interval can be then removed.
>
>
> Agreed. I've simplified the display of this.
>
> >> day-of-the-month-range = "between" WSP day-of-the-month WSP "and"
> WSP day-of-the-month
> >>
> >> day-of-the-month = "-31" to "31"
>
> > This notion allows me to enter "between -31 and 3" which does not
> make any sense.
>
> I'll clarify with "-31" to "-1" OR "0" to "31".
>
> > Also current grammar does not allow me to use ranges which I want to
> use here.
>
> Please explain what range you want here. I'm specifically avoiding
> "intervals" here because it's too complex to understand.

I think it is very simple:

a) I want to use explicit days by number I use this:
periodic monthly day 1,3,5,10-15,22
b) I want to use week days during an interval I use this:
periodic monthly day on Wed, Sun during 1,3,5,10-15,22

I want to use same interval definition in both cases.
>
> Describing events with arbitrary intervals like this would be better
> done with the M-day approach.
>
>
> > I want to be able to express "Wednesday" of the first and third week
> of the month. Capability to do so it completely lost.
>
> Wrong. accessTime is multivalued. You just create two entries, one for
> the first week, one for the third week. They are additive.

Yes you can but I think it is not an acceptable solution. I should be
able to express it in one rule.


>
> > We abandoned the term "septet" not because of the bad idea but
> because this is a confusing word. But we can leave without it as long
> as I can use complex intervals.
> > After more thinking I would like to reject idea of the negative numbers.
> > Instead we can do the following:
>
>
> > M-on = "on" WSP day-of-the-week WSP "during" WSP day-of-the-month-range
> > day-of-the-month-range = interval 1-31 / last-days
> > last-days = "last" WSP sequential-days
> > sequential-days = single number from the 1-31 range
>
> > So if we want to say "Wednesday" of the first and third week of the
> month I will use:
>
> > periodic monthly on Wed during 1-7,15-21
>
> > if I want to say Wednesday during last two weeks of the month I will
> say:
>
> > periodic monthly on Wed during last 14
>
> > IMO it is cleaner and simpler and allows to express all the notions
> we want to express.
>
>
> See above. I really don't want intervals in the M-on grammar, since it
> makes it extremely difficult to comprehend by mere mortals.

And I really want them there.

>
>
> >> day-of-the-week = interval 1-7 (or Mon-Sun)
> >>
> >> range-specifier = "at" WSP HHMM WSP "+" WSP duration-specifier
> > What is the value and significance of the "+" here? Is it just for
> readability? Then I would suggest that we replace it with the word "for".
>
>
> Sure, "for" is fine.
>
> >> duration-specifier = DDHHMM
> >>
> >> DD = "00" to "31"
> >>
> >> HH = "00" to "23"
> >>
> >> MM = "00" to "59"
> >>
> >>
> >> interval XX-YY = a comma-separated list of items from XX to YY, or
> dash-separated ranges.
> >> range = dash-separated range
> > This definition seems incomplete but I do not know how to make it
> better...
>
> >> For example, (interval 1-31) 3-7,10,12,15,25-31 with no spaces inside.
>
> > Thank you,
> > Dmitri Pal
>
> > Sr. Engineering Manager IPA project,
> > Red Hat Inc.
>
>
> > -------------------------------
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> > www.redhat.com/carveoutcosts/
>
> > _______________________________________________
> > Freeipa-devel mailing list
> > Freeipa-devel at redhat.com
> > https://www.redhat.com/mailman/listinfo/freeipa-devel
>
>
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-- 
Thank you,
Dmitri Pal

Sr. Engineering Manager IPA project,
Red Hat Inc.


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