Hi Francis,

I actually had considered the cron approach, but wasn't sure if it was
the best way to do things. What you say makes a lot of sense (I was
already nervous about the watchdog running into trouble, and there are
no coordination requirements), so I will go with your suggestion.

Thanks!
Krishna

On 9/29/06, Francis Cianfrocca <garbagecat10 / gmail.com> wrote:
> On 9/29/06, Krishna Dole <dontfall / gmail.com> wrote:
> >
> > Hi all,
> > If anyone is willing, I'd be grateful for some advice on the forking
> > job scheduler I've written. It works fine in simple tests, but does
> > not feel elegant. On IRC kbrooks recommended an asynchronous main
> > loop, but i don't understand how to implement that in this situation.
> > The first version I wrote used threads, but several sources
> > recommended fork instead. I have also considered just using the shell
> > command 'ps' to see how many jobs are running, launching more as
> > needed.
> >
> > The basic requirements:
> > - Each job is a long-running external process (taking a day or more)
> > and all jobs require a different amount of time to run (so
> > asynchronous launching will be needed).
> > - I want to keep N jobs running at all times (N = 4 in the example below)
>
>
>
> You say nothing about the coordination requirements of the external
> processes with the "watchdog" process. Is your requirement really just to
> ensure that four jobs are running at all times? If so, I would avoid using a
> long-running watchdog process, because you're making an assumption that it
> will never crash, catch a signal, etc. Why not run a cron job every five
> minutes or so that checks the running processes (via pgrep or ps as you
> suggested), starts more if necessary, writes status to syslog, and then
> quits? Much, much easier.
>
>