[dundee] Noob Programming Question

[Gary Short]

Thanks, I'll take a look at upstart

> -----Original Message-----
> From: dundee-bounces at lists.lug.org.uk [mailto:dundee-
> bounces at lists.lug.org.uk] On Behalf Of Robert McWilliam
> Sent: 15 March 2010 17:11
> To: Tayside Linux User Group
> Subject: Re: [dundee] Noob Programming Question
> 
> On Mon, 15 Mar 2010 15:37 +0000, "Gary Short" <gary at garyshort.org>
> wrote:
> > Hi Guys,
> >
> > I was wondering if anyone here can give me some help. What I'm trying
> to
> > do
> > is to run curl and pipe the output to file1, then after a time t,
> stop
> > curl
> > and restart it piping it's output to file2 and so on to fileN, so
> that I
> > can
> > use another script to process the files, something like this...
> >
> 
> I'd use python for this. It has pretty good support for creating and
> managing subprocesses, throw in time.sleep() for the waiting and the
> whole thing is pretty straight forward. I could probably knock together
> a script pretty quickly (I already have scripts doing similar things
> where so let me know if you want that.
> 
> > I also need a script to monitor this first one so that if it dies it
> can
> > be
> > restarted, something like...
> >
> > If script_is_not_running:
> >    Arg = digits_at_end_of_newest_file
> >    Run script arg
> 
> Such a script is trivial in most languages. I'd use python again
> because
> I find regexps to be a nightmare in bash.
> 
> If I were writing this I'd actually give up on the whole idea of saving
> and initialising the counter though and write a function to create the
> next file by looking at which ones are there already (pretty much the
> implementation of "Arg = digits_at_end_of_newest_file" from your
> monitoring script) as that means that you don't have any state in the
> script any more and the monitoring becomes a trivial infinite loop
> launching the script again if it exits. It will mean more processing in
> the script to go and calculate the counter each time but if the time
> that curl is running is reasonably big, and you don't have a filesystem
> with terrifying slow reads, then I wouldn't think it'll be an issue.
> 
> You can use the daemon managing software to do the monitoring side of
> things, it should have conventions to make it easy for you to have the
> script report errors if it needs to be respawned. I think upstart was
> in
> use by 8.04 so would the the Right Way to look after a daemon but if
> not
> init scripts do work.
> 
> 
> Robert
> ________________________________________________________
> Robert McWilliam     rmcw at allmail.net    www.ormiret.com
> 
> The opinions expressed herin are not necessarily those of my
> employer, not necessarily mine, and probably not necessary.
> 
> 
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