Asp Forum - Re: Timers, scheduling and Ruby

Lipper, Matthew

12/1/2006 6:37:00 PM

>
> On 12/1/06, ara.t.howard@noaa.gov <ara.t.howard@noaa.gov> wrote:
> > On Fri, 1 Dec 2006, Pit Capitain wrote:
> >
> > > ara.t.howard@noaa.gov schrieb:
> > >> how bout this as the time spec?
> > >>
> > >> http://runt.ruby...
> > >
> > > Ara, this would be nice, but I think it's difficult to
> determine the time of
> > > the next event with Runt's temporal expressions. I'm sure
> you don't want to
> > > call Runt::TExpr#include? every n seconds.
> >
> > indeed. this is the only major design flaw. still, if one
> assumes a
> > granualrity of not more than 60s (ala cron) then this
> approach isn't too bad.
> > between the dates/include methods one can determine apriori
> if an event should
> > be scheduled for the next minute 'tick'.
> >
> > i'm assuming there is either a solution implied in the code
> or that one can be
> > added without too much trouble - the bulk of the work has
> already been done in
> > this lib, so even if it isn't there now, i'm sure a
> solution will present
> > itself.
> >
> > now. what do you suggest?
> >
>
> Runt looks nice. Another package is Chronic. It was part of the
> natural language processing presentation at RubyConf this year. All
> Chronic does, though, is take human "fuzzy" times and turns them into
> actual Time objects.
>
> Chronic.parse "next Thursday at seven am" #=> Time object
>
> http://rubyforge.org/project...
>
> What is needed to make Runt work for a scheduler is a next_time method
> that would return the next Time that this event should happen given
> Time.now. The scheduler then maintains a queue of the "next time" for
> all events and pulls them from the queue in order. When an event runs,
> the last thing it does is pulls the next_time from Runt and adds that
> to the queue (in the proper location). The scheduler thread then
> sleeps for N seconds where N is the time till the next event in the
> queue needs to happen.
>
> So, maybe a combination of Chronic (to get the nice human readable
> format) and Runt (to keep track of recurring events) would work?
>
> TwP
>
>

I'm still catching up to this thread but FWIW I am always interested in
making Runt more useful and functional. If I understand the above
correctly, then you'd like a next_time method returning a
Date/DateTime/Time (or whatever) that indicates the next occurrence of
this expression?

Matt

__mlipper__at__gmail_dot_com__

2 Answers

Tim Pease

12/1/2006 7:25:00 PM

On 12/1/06, Lipper, Matthew <Mlipper@doitt.nyc.gov> wrote:
> >
> > On 12/1/06, ara.t.howard@noaa.gov <ara.t.howard@noaa.gov> wrote:
> > > On Fri, 1 Dec 2006, Pit Capitain wrote:
> > >
> > > > ara.t.howard@noaa.gov schrieb:
> > > >> how bout this as the time spec?
> > > >>
> > > >> http://runt.ruby...
> > > >
> > > > Ara, this would be nice, but I think it's difficult to
> > determine the time of
> > > > the next event with Runt's temporal expressions. I'm sure
> > you don't want to
> > > > call Runt::TExpr#include? every n seconds.
> > >
> > > indeed. this is the only major design flaw. still, if one
> > assumes a
> > > granualrity of not more than 60s (ala cron) then this
> > approach isn't too bad.
> > > between the dates/include methods one can determine apriori
> > if an event should
> > > be scheduled for the next minute 'tick'.
> > >
> > > i'm assuming there is either a solution implied in the code
> > or that one can be
> > > added without too much trouble - the bulk of the work has
> > already been done in
> > > this lib, so even if it isn't there now, i'm sure a
> > solution will present
> > > itself.
> > >
> > > now. what do you suggest?
> > >
> >
> > Runt looks nice. Another package is Chronic. It was part of the
> > natural language processing presentation at RubyConf this year. All
> > Chronic does, though, is take human "fuzzy" times and turns them into
> > actual Time objects.
> >
> > Chronic.parse "next Thursday at seven am" #=> Time object
> >
> > http://rubyforge.org/project...
> >
> > What is needed to make Runt work for a scheduler is a next_time method
> > that would return the next Time that this event should happen given
> > Time.now. The scheduler then maintains a queue of the "next time" for
> > all events and pulls them from the queue in order. When an event runs,
> > the last thing it does is pulls the next_time from Runt and adds that
> > to the queue (in the proper location). The scheduler thread then
> > sleeps for N seconds where N is the time till the next event in the
> > queue needs to happen.
> >
> > So, maybe a combination of Chronic (to get the nice human readable
> > format) and Runt (to keep track of recurring events) would work?
> >
> > TwP
> >
> >
>
> I'm still catching up to this thread but FWIW I am always interested in
> making Runt more useful and functional. If I understand the above
> correctly, then you'd like a next_time method returning a
> Date/DateTime/Time (or whatever) that indicates the next occurrence of
> this expression?
>

Bingo!

From the tutorial example ...

last_thursday = DIMonth.new(Last_of,Thursday)
august = REYear.new(8)
expr = last_thursday & august

expr.next_time #=> or some equally clever method name

Here returns the Time object that represents the last Thursday in
August -- probably midnight since that is when Thursday starts.

mon_wed_fri = DIWeek.new(Mon) | DIWeek.new(Wed) | DIWeek.new(Fri)
mon_wed_fri.next_time

Since today is Friday, this example would return the Time object that
represents the next Monday from today.

Maybe just "next" instead of "next_time" ??

Any chance of getting Runt and Chronic to play nicely together?

Blessings,
TwP

Ara.T.Howard

12/1/2006 7:40:00 PM

comp.lang.ruby

Re: Timers, scheduling and Ruby

Lipper, Matthew

Tim Pease

Ara.T.Howard

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