Re: [Condor-devel] RFC: an implementation of classads enhanced with macro evaluation

[Erik Erlandson <eje@xxxxxxxxxx>]

On Wed, 2012-03-14 at 12:32 -0500, Erik Paulson wrote:
>  The configuration
> process relies on a known-order and precdence in intrepreting the files,
> and some thought was given with how it would interact and behave like
> other systems that most Condor administrators manage at the same time
> as Condor and follow some of the conventions from those communities.

I would propose keeping the same scheme, just with classads.  Allowing
multiple files, with precedence given to most-recently-read, etc.

> 
> If Condor went to using a serialized ClassAd as its configuration system, 
> it would be the only thing in the universe that does so. Is that really a
> win for the pool administrators?

But isn't condor also the only thing in the universe that uses condor's
configuration file format?  Which, as you say, already makes use of
classad expressions for RHS values.  

I don't see any fundamental user-experience down side to going the rest
of the way and providing a path to leveraging the remaining capabilities
of the language.  That is, aside from the intimidating backward
compatability issues, software churn, etc.


>  Perhaps Condor would be
> better off by thinking about ways to make the ClassAd expressions easier
> to store in a different semi-structured format.

I've heard "subset of javascript" and JSON proposed as alternatives,
which could be supported via additional grammars. xml is already
supported.


> > I admit to having some geeky plans for writing a spec-compliant
> > implementation of classads for C++, in my copious spare time.
> > 
> 
> To each their own, of course, but isn't the current ClassAd implemention
> both in C++ and already reasonably close to the spec?

I think it's faithful to the spec.  I had a short list of "missing" spec
features in mind that I sanity-checked last evening, and in fact they
aren't missing.  The parser provides them, so I had some crow for
breakfast this morning on that one.