Re: [camp] [OASIS Issue Tracker] Commented: (CAMP-4) Need a formal specification of the PDP format

[Adrian Otto <adrian.otto@rackspace.com>]

Jacques,

On Mar 20, 2013, at 7:37 PM, "OASIS Issues Tracker" <workgroup_mailer@lists.oasis-open.org> wrote:
> 
>    [ http://tools.oasis-open.org/issues/browse/CAMP-4?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=32805#action_32805 ] 
> 
> Jacques Durand  commented on CAMP-4:
> ------------------------------------
> 
> The merging of  issue CAMP-21 actually raises questions beyond just the PDP:
> 
> - Should an assemblyTemplate have a unique signature in terms of its resource components (at least as far as its Application Component Templates is concerned), that does not vary across Providers?
> 
> The diagram from Gil in #21 suggests not.

No. Implementers should have the freedom to interpret the arrangement of an assembly differently.

> But in section 5, def of AssemblyTemplates suggests yes:
> "The platform shall instantiate the Application Components and their configurations  as specified in the definition of the Assembly Template."  Which is a fairly common expectation from a modeling viewpoint:  ADEs will generate AssemblyTemplates composed of ACTs and other Component Requirements. It will be expected that  different Providers respect this composition.

Yes, indeed. Two platforms can conform to this requirement and produce assemblies that differ.

> Re-reading the definition of #21: "One provider could choose to model this application as an Assembly Template with a single Application Component Template ..."
> I think it would be cleaner if we decide that "templates" and their contents are precisely what Providers cannot modify , while "instances" are where Providers exercise their interpretation rights (e.g. when matching a component with requirements). Do we really need some interpretation flexibility "above" instances level? 

I think that's actually what Gil was trying to convey when he wrote that. The templates are not generated by the Platform, but the instances are. A platform should not change a template. It would vary what components are arranged in an assembly.

Adrian