[OASIS Issue Tracker] (CAMP-201) Consumer mutability of attribributes and attribute types

[OASIS Issues Tracker <workgroup_mailer@lists.oasis-open.org>]

    [ https://issues.oasis-open.org/browse/CAMP-201?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=61254#comment-61254 ] 

Alex Heneveld commented on CAMP-201:
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As discussed on the call tonight:

* we think consumer mutable and PUT/PATCH are useful for plans / templates, and for just a few pieces of metadata on instances (name, description)
* mutable is useful mainly for a client to know what he can safely cache, mostly identifiers and URI's

A simpler approach than the current mutable / consumer-mutable (on types and not on instances where they matter!) might be:

* to say for plans and templates that PUT shall be supported as a way to make changes
* to say on selected other attributes (name, description) that PUT shall be supported as a way to make changes
* to say on selected attributes (id/url) that the server must not change the values of those attributes

And beyond this to say nothing; an impl may support PUT elsewhere but there is no requirement or expectation that this be done.  The normal ways to make other changes (most changes) are:

* POST to deploy an app or add a plan
* POST to an effector to invoke a change on a running instance

I think this would resolve the issue and also very much simplify the spec.

People will evolve extensions to suggest supported values and runtime documentation e.g. when changing items on plans (a UI dropdown, or code completion, etc), and when we have some consensus there we can then incorporate it into the spec.  That is better than something half-baked in this area which I think we currently have.

> Consumer mutability of attribributes and attribute types
> --------------------------------------------------------
>
>                 Key: CAMP-201
>                 URL: https://issues.oasis-open.org/browse/CAMP-201
>             Project: OASIS Cloud Application Management for Platforms (CAMP) TC
>          Issue Type: Bug
>          Components: Spec
>    Affects Versions: 1.2
>            Reporter: Anish Karmarkar
>            Assignee: Anish Karmarkar
>            Priority: Critical
>
> The spec currently defines consumer mutability of an attribute in the attribute type definition. Questions have been raised about whether that is appropriate. Few scenarios that complicate this:
> 1) Collection type 'items' attribute may be mutable or not depending on the kind of collection.
> 2) the consumer mutability of an attribute may depend on an instance not the type. Moving this to the type necessitates unnecessary invention of additional types
> 3) the mutability of an attribute may depend on other factors such as authorization/credentials of the consumer or it may change with time (because changing the attribute value may make something else inconsistent).
> Issues 180, 196, and 199 depend on resolution of this issue.



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