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Re: Question regarding the availability of services (and resources)

From: Phil Archer <parcher@icra.org>
Date: Fri, 20 Jul 2007 11:32:26 +0100
Message-ID: <46A08F3A.2040602@icra.org>
To: "Hausenblas, Michael" <michael.hausenblas@joanneum.at>
CC: SWD WG <public-swd-wg@w3.org>, public-powderwg@w3.org

Michael,

I may have misunderstood but I'm not sure that POWDER is the best helper 
here. We deal with generalised metadata that can be applied to lots of 
things at once rather than the sort of use case you describe.

That said, I can see that we're going to face the same issue before 
long. Some of us are working on a project that will see a service that 
will handle Description Resources and talk to its clients over SOAP (the 
inevitable SOAP-POWDER made manifest...) but if our service is slow, 
clients will want to talk to a mirror or some other service. Hmmm... 
maybe this is a job for the Rule Interchange Format folk 
(http://www.w3.org/2005/rules/)?

Phil.

Hausenblas, Michael wrote:
> 
> All,
> 
> I've got a (maybe dumb) question regarding the availability of
> services (and resources), or better say how to describe and handle this.
> This may as well concern the 'Best Practice Recipes for Publishing RDF
> Vocabularies' deliverable [1], but might also touch POWDER-WG [2] issues
> -
> I'm unsure about it ...
> 
> 
> Now, here comes our problem. When developing SW applications, we
> frequently 
> encounter the following situation: Say, there are two external services
> A and B.
> In our SW application I'd like to state that per default service A
> should be used,
> but in case A is not available (or has too big latency), service B must
> be used.
> 
> What I've gathered so far (but I must admit, I did not read each and
> every post in all the mailing lists ;) is that:
> 
> + The 'POWDER: Use Cases and Requirements' document [3] also tackles
>   this issues, IMHO, but I can't find a hook for our problem;
> 
> + The Web Services Policy Working Group [4] has published a policy
>   model in its 'Web Services Policy 1.5 - Framework' [5]; though AFAIK
>   this is not based on RDF, and I don't know if REST-interfaces are
> addressed
>   equally.
> 
> So, I guess the question would be: Is there a common (RDF-based)
> vocabulary
> (along with some standardised rules) available that would allow us to
> handle
> the above described setup on a generic, declarative level?
> 
> Any thoughts & pointers welcome!
> 
> Cheers,
> 	Michael
> 
> BTW: Please note that - in my understanding - the same might 
>      be applicable for resources (or repositories), and equally
>      one could extend it regarding QoS issues.
> 
> [1] http://www.w3.org/TR/2006/WD-swbp-vocab-pub-20060314/
> [2] http://www.w3.org/2007/powder/
> [3] http://www.w3.org/TR/2007/NOTE-powder-use-cases-20070525/
> [4] http://www.w3.org/2002/ws/policy/
> [5] http://www.w3.org/TR/2007/PR-ws-policy-20070706/
> 
> ----------------------------------------------------------
>  Michael Hausenblas, MSc.
>  Institute of Information Systems & Information Management
>  JOANNEUM RESEARCH Forschungsgesellschaft mbH
>  Steyrergasse 17, A-8010 Graz, AUSTRIA
> 
>  <office>
>     phone: +43-316-876-1193 (fax:-1191)   
>    e-mail: michael.hausenblas@joanneum.at
>       web: http://www.joanneum.at/iis/ 
> 
>  <private>
>    mobile: +43-660-7621761
>       web: http://www.sw-app.org/ 
> ----------------------------------------------------------
> 
Received on Friday, 20 July 2007 10:32:45 GMT

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