periodic task library

[aparajita]

Hi,

I had the occasion to need periodic tasks for a project I'm working  
on, and came up with a generic a4d.tasks library. Here is the current  
design:

create(inMethodToExecute; inPeriodInMinutes {; inData {; inLimit}}) ->  
longint
- inMethodToExecute must be a globally accessible Active4D library  
method with the following signature:

method "myTask"($inId; $inAction; $ioData)
- inId is the task id
- inAction is "init", "exec", or "deinit"
- ioData is the data that was passed into 'create task'
- you may call 'delete($inId)' within this method to cause the task to  
be deleted on the next run

- inPeriodInMinutes is how long between calls, >= 1. No guarantee the  
task will be run that often, it is actually the minimum number of  
minutes between calls, since the queue is only checked every 10 seconds
- inData if passed and non-zero must be a *global* collection, it will  
be cleared with 'deep clear collection' when the task is deleted
- inLimit if passed is the number of times you want the task to be  
executed, after which it will be removed, < 0 means unlimited

delete(inId)
- remove the task and deep clear its data
- if called from a currently running task, marks it for deletion on  
the next run

dump
- Dumps the task list to the A4D console


I would like any comments or suggestions before I release it as part  
of the Active4D standard libs. The task runner will be a 4D method  
running in a separate process that calls a4d.tasks.execute every 10  
seconds.

Typically in one of your libraries, you would do something like this:

method "__load__"
    self{"mytask"} := a4d.tasks.create("mylib.mytaskHandler"; 1)
end method

method "__unload__"
    ad4.tasks.delete(self{"mytask"})
end method

method "mytaskHandler"($id; $action; $data)
    case of
       :($action = "init")
          // do some init

       :($action = "exec")
          // run my task

       :($action = "deinit")
          // cleanup
    end case
end method


Kind regards,

    Aparajita
    www.aparajitaworld.com

    "If you dare to fail, you are bound to succeed."
    - Sri Chinmoy   |   www.srichinmoy.org

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[Michael Kaye-4]

Thanks Aparajita,

I'm back to working with A4D next week so will have a look at this.

Sounds like a great feature...

Regards, Michael.

On 24 Oct 2009, at 21:47, Aparajita Fishman wrote:

> Hi,
>
> I had the occasion to need periodic tasks for a project I'm working  
> on, and came up with a generic a4d.tasks library. Here is the  
> current design:
>
> create(inMethodToExecute; inPeriodInMinutes {; inData {; inLimit}}) -
> > longint
> - inMethodToExecute must be a globally accessible Active4D library  
> method with the following signature:
>
> method "myTask"($inId; $inAction; $ioData)
> - inId is the task id
> - inAction is "init", "exec", or "deinit"
> - ioData is the data that was passed into 'create task'
> - you may call 'delete($inId)' within this method to cause the task  
> to be deleted on the next run
>
> - inPeriodInMinutes is how long between calls, >= 1. No guarantee  
> the task will be run that often, it is actually the minimum number  
> of minutes between calls, since the queue is only checked every 10  
> seconds
> - inData if passed and non-zero must be a *global* collection, it  
> will be cleared with 'deep clear collection' when the task is deleted
> - inLimit if passed is the number of times you want the task to be  
> executed, after which it will be removed, < 0 means unlimited
>
> delete(inId)
> - remove the task and deep clear its data
> - if called from a currently running task, marks it for deletion on  
> the next run
>
> dump
> - Dumps the task list to the A4D console
>
>
> I would like any comments or suggestions before I release it as part  
> of the Active4D standard libs. The task runner will be a 4D method  
> running in a separate process that calls a4d.tasks.execute every 10  
> seconds.
>
> Typically in one of your libraries, you would do something like this:
>
> method "__load__"
>   self{"mytask"} := a4d.tasks.create("mylib.mytaskHandler"; 1)
> end method
>
> method "__unload__"
>   ad4.tasks.delete(self{"mytask"})
> end method
>
> method "mytaskHandler"($id; $action; $data)
>   case of
>      :($action = "init")
>         // do some init
>
>      :($action = "exec")
>         // run my task
>
>      :($action = "deinit")
>         // cleanup
>   end case
> end method
>
>
> Kind regards,
>
>   Aparajita
>   www.aparajitaworld.com
>
>   "If you dare to fail, you are bound to succeed."
>   - Sri Chinmoy   |   www.srichinmoy.org
>
> _______________________________________________
> Active4D-dev mailing list
> Active4D-dev@...
> http://mailman.aparajitaworld.com/mailman/listinfo/active4d-dev
> Archives: http://mailman.aparajitaworld.com/archive/active4d-dev/

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[AppleII717]

On Oct 24, 2009, at 3:47 PM, Aparajita Fishman wrote:

> I would like any comments or suggestions before I release it as part  
> of the Active4D standard libs. The task runner will be a 4D method  
> running in a separate process that calls a4d.tasks.execute every 10  
> seconds.

I assume this process is running on the machine running Active4D. We  
created a cron task in 4D that could call Active4D code. Can't  
remember all the details, but our missing logic was that the cron task  
was running on the server and Active4D was running on a 4d client (no  
Active4D or web license on the server). Since we needed it for both 4D  
and Active4D, we just gave up the Active4D side (guess we could have  
used execute on client - but I'm not a 4D person). For the Active4D  
stuff, we just created a cron task in Mac OS that would generate a  
curl to a controller script.

Your library approach would probably simplify that process.

Steve Alex
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[aparajita]

> I assume this process is running on the machine running Active4D.

Yes, it only runs on that machine if Active4D is running on the machine.

Kind regards,

    Aparajita
    www.aparajitaworld.com

    "If you dare to fail, you are bound to succeed."
    - Sri Chinmoy   |   www.srichinmoy.org

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