[occi-wg] Templates (was Re: OCCI Dashboard)

[eprparadocs at gmail.com]

Geez I wish people would stop the RESTful is OO vs. RPC is functional. 
Nothing could be further from thhe truth. RESTful, RPC, SOAP, XML RPC
are all remote calls. It has nothing at all to do with functional vs.
imperative programming. That comes from something else, the definition
of the language.

RESTful is functional, it just deals with objects (or it can). The same
can be said of RPC, after all Corba is object based use of "RPC".

Chance

Sam Johnston wrote:
> On Thu, Jun 25, 2009 at 8:29 PM, <shlomo.swidler at gmail.com
> <mailto:shlomo.swidler at gmail.com>> wrote:
>
>     > A template is just a special type of compute resource and
>     there's nothing to
>     > say we're not going to end up with template network and storage
>     resources as
>     > well - I really don't think a new noun is justified and would
>     prefer to keep
>     > things as simple as possible... 3 nouns is about right.
>     >
>     > Sam
>
>     I'm still warping^H^H^H^H^H wrapping my head around RESTful thinking
>     as opposed to OO, so please bear with me.
>
>
> That's ok... in fact RESTful interfaces are usually fairly OO - what I
> call ROA is just taking it to the extreme. Most people are still
> thinking like functional programming (e.g. RPC-style), as reflected in
> APIs like Amazon EC2.
>  
>
>     If both "AMI"s (template-computes) and "instances" (actual-computes)
>     are "compute" resources, then how would the client distinguish between
>     the two? One reason to distinguish between them is to separately
>     classify them into different areas of the UI (for example the "Images"
>     vs. Instances" tabs of ElasticFox) based on the verbs that can be done
>     to them.
>
>
> The simplest solution for this is to add templates to a "template"
> category. In fact we could specify a number of well known categories
> like "validated", "[in]secure", etc.
>  
>
>     On second thought, I may have answered my own question: we can
>     distinguish template-computes from actual-computes by looking at the
>     verb links that are provided on them. Actual-computes will have verbs
>     such as "start","stop", "pause", "resume", "delete" (depending on
>     their current state); while template-computes will only have "start"
>     and "delete", and their state will never change (not sure, but it
>     seems to me that a template's state will not change - you can only
>     create a new resource from a template or delete the template
>     altogether).
>
>
> Exactly, only there may be conditions where machines in transition or
> in abnormal/error states appear as templates when they should not. I'm
> not yet sure whether we need to explicitly state that a machine is a
> template (or just rely on the presence or absence of verbs like
> "clone" and "start" respectively)... but I am sure that they are the
> same noun.
>  
>
>     Then again, if an infrastructure provider does not allow
>     actual-computes to be "paused" or "resumed" but does allow "start" and
>     "stop", then we cannot distinguish between actual-computes that are
>     stopped (having verbs "start" and "delete") and between
>     template-computes (having verbs "start" and "delete").
>
>
> Right. It's also possible that user permissions will confuse things -
> perhaps a failover operator can start but not stop machines for example.
>  
>
>     So then the question remains: how do we reliably distinguish between
>     template-computes and actual-computes? Or template-XXs and actual-XXs
>     ?
>
>
> I'm thinking categories - we already have a category system that will
> handle this well and can even have a dedicated vocabulary/schema for
> our well-defined categories.
>
> Sam
>
> ------------------------------------------------------------------------
>
> _______________________________________________
> occi-wg mailing list
> occi-wg at ogf.org
> http://www.ogf.org/mailman/listinfo/occi-wg
>