Quoting [Alexis Richardson] (May 12 2009):
Andy
It's not completely obvious to me how people can interoperate on just a model, nor how normative renderings can be plural.
That is indeed difficult to define, IMHO. My (biased) example is the SAGA spec in OGF (Simple API for Grid Applications): the API specification is language neutral, but several renderings for Java, C++, Python etc exist, and will be normative in their own right (spec documents are WIP). The abstract specification includes a number of syntactic and (more so) semantic guidelines which MUST be followed by the renderings, to maintain common nouns, verbs and attributes (no surprise, he?). But language specific deviations are allowed, were sensible (error handling, booststrapping, etc). Interopn can indeed only effectively defined for the individual renderings. We believe, however, that implementations of different renderings are assumed interoperable, if the respective test suites result in the same backend operations. For SAGA, that is difficult to prove - the API is too large for that. For OCCI, with its limites set of nouns/verbs/attribs, that may very well be possible. FWIW, other APIs in OGF went a similar route, most notably DRMAA. Their original spec is in C, but after several renderings emerged for Java, Python, etc, a language neutral spec (IDL) was created to derive these bindings from. Interop again is defined via test suites. Note: a different to OCCI is that neithe SAGA nor DRMAA talk about protocols, but *only* about client side APIs, rendered in higher level programming languages. My $0.02, Andre.
alexis
On Tue, May 12, 2009 at 11:53 AM, Edmonds, AndrewX <andrewx.edmonds@intel.com> wrote:
I'd (again) agree with this and would re-iterate Alexander's (Papaspyrou) earlier point on approach and process:
"The canonical way to cope with this issue [formats] (which, by the way, has proved right many times in the past) in many WGs within OGF is to separate this step not only in design, but also in specification: have an abstract "modeling" part in the spec which clearly defines the semantics the data, and one or more normative renderings for the abstract model."
It would also seem to me that although we have the noun-verb-attribute reasoning it might need to be expressed in an easier form to communicate, say graphically.
Andy
-----Original Message----- From: occi-wg-bounces@ogf.org [mailto:occi-wg-bounces@ogf.org] On Behalf Of Roger Menday Sent: 12 May 2009 11:43 To: Richard Davies Cc: occi-wg@ogf.org Subject: Re: [occi-wg] Simple JSON rendering for OCCI
On 12 May 2009, at 11:20, Richard Davies wrote:
Therein lies the problem - there are no "standard tools" nor any way to specify a cross-platform mechanical transform for JSON (at least not yet).
Yes, I agree with you there - if we're going with multiple formats it'll be easier to define XML -> JSON than JSON -> XML.
Hi Richard,
Rather than transforming across the actual formats, there seems to be a interest in defining a model and then describe how to render onto various data formats. So, rendering-down, rather then transforming- across. (?)
The data formats discussion is a tricky one to resolve, as there's things to like in each of JSON, ATOM and key-value. That said, the "compliant, but non-interoperable implementations through supporting multiple representations" is a strong argument for a single format. Whatever that may be ...
regards Roger
Richard. _______________________________________________ occi-wg mailing list occi-wg@ogf.org http://www.ogf.org/mailman/listinfo/occi-wg
Roger Menday (PhD) <roger.menday@uk.fujitsu.com>
Senior Researcher, Fujitsu Laboratories of Europe Limited Hayes Park Central, Hayes End Road, Hayes, Middlesex, UB4 8FE, U.K. Tel: +44 (0) 208 606 4534
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