[ClusterLabs] ocf scripts shell and local variables

[Dejan Muhamedagic]

Hi,

On Tue, Aug 30, 2016 at 09:32:54AM +0200, Kristoffer Grönlund wrote:
> Jehan-Guillaume de Rorthais <jgdr at dalibo.com> writes:
> 
> > On Mon, 29 Aug 2016 10:02:28 -0500
> > Ken Gaillot <kgaillot at redhat.com> wrote:
> >
> >> On 08/29/2016 09:43 AM, Dejan Muhamedagic wrote:
> > ...
> >>> I doubt that we could do a moderately complex shell scripts
> >>> without capability of limiting the variables' scope and retaining
> >>> sanity at the same time.
> >> 
> >> This prefixing approach would definitely be ugly, and it would violate
> >> best practices on shells that do support local, but it should be feasible.
> >> 
> >> I'd argue that anything moderately complex should be converted to python
> >> (maybe after we have OCF 2.0, and some good python bindings ...).
> >
> > For what it worth, I already raised this discussion some month ago as we wrote
> > some perl modules equivalent to ocf-shellfuncs, ocf-returncodes and
> > ocf-directories. See: 
> >
> >   Subject: [ClusterLabs Developers] Perl Modules for resource agents (was:
> >     Resource Agent language discussion) 
> >   Date: Thu, 26 Nov 2015 01:13:36 +0100
> >
> > I don't want to start a flameware about languages here, this is not about that.
> > Maybe it would be a good time to include various libraries for different
> > languages in official source? At least for ocf-directories which is quite
> > simple, but often tied to the configure options in various distro. We had to
> > make a ugly wrapper around the ocf-directories librairie on build time to
> > produce our OCF_Directories.pm module on various distros.
> >
> 
> I don't know Perl so I can't be very helpful reviewing it, but please do
> submit your Perl OCF library to resource-agents if you have one! I don't
> think anyone is opposed to including a Perl (or Python) API on
> principle, it's just a matter of someone actually sitting down to do the
> work putting it together.

Sure, I doubt that anybody would oppose that. Looking at the
amount of the existing supporting code, it is not going to be a
small feat.

***

This is off-topic and I really do hope not to start a discussion
about it so I'll keep it short: I often heard shell programming
being bashed up to the point that it should be banned. While it
is true that there are numerous scripts executed in a way leaving
much to be desired, the opposite is certainly possible too. Shell
does fit well a certain type of task and resource agents
(essentially more robust init scripts) belong to that realm.

Thanks,

Dejan


> Cheers,
> Kristoffer
> 
> -- 
> // Kristoffer Grönlund
> // kgronlund at suse.com
> 
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