[Koha-devel] Task schedulers and message queues for Koha

[David Cook]

Hi Zeno,

Thanks for your message.

Originally, I developed the OAI-PMH harvester using a cronjob, but that
wasn't acceptable for Stockholm University Library for a few reasons.

One, there was no web interface for controlling it. Two, they wanted to
execute OAI-PMH requests every 2-3 seconds and cron has 1 minute as its
finest granularity. Three, even if you setup a cronjob to run every minute,
long running tasks could get duplicated (although you could mitigate that
with locks which would be a pain). Plus, you want to run tasks in parallel,
so you're going to want to use multiple processes, which cron isn't really
set up to achieve. 

At the end of it, I think it's more 'to purpose' to have your own daemon
where you can control time intervals, workers, have a web interface, etc. 

Cron is useful for many purposes, but I don't think it's always the right
solution. Plus, creating a web interface for cron isn't necessarily the best
idea I think. I would consider it to be a hack rather than a solution. As
others have pointed out before me, it comes with significant security
issues. With a task scheduler, you're much more in control of everything.  

David Cook
Systems Librarian
Prosentient Systems
72/330 Wattle St
Ultimo, NSW 2007
Australia

Office: 02 9212 0899
Direct: 02 8005 0595


> -----Original Message-----
> From: Tajoli Zeno [mailto:z.tajoli at cineca.it]
> Sent: Wednesday, 22 February 2017 12:28 AM
> To: David Cook <dcook at prosentient.com.au>; koha-devel at lists.koha-
> community.org
> Subject: Re: [Koha-devel] Task schedulers and message queues for Koha
> 
> Hi David,
> 
> Il 20/02/2017 02:01, David Cook ha scritto:
> > In 2016, I worked on a Koha task scheduler for downloading and
> > importing records via OAI-PMH. I have code which works, but it's
> > lacking test coverage and I'm unsure that it will make it through QA and
be
> accepted.
> 
> for me is not 100% clear why do you use a Task scheduler.
> Why do you no manage queues only with cron ?
> At least we need a web interface to setup cron.
> 
> Bye
> Zeno Tajoli
> 
> 
> --
> Zeno Tajoli
> /SVILUPPO PRODOTTI CINECA/ - Automazione Biblioteche
> Email: z.tajoli at cineca.it Fax: 051/6132198
> *CINECA* Consorzio Interuniversitario - Sede operativa di Segrate (MI)