[wildfly-dev] Management model attribute groups

[Brian Stansberry]

On 12/10/14, 10:06 AM, David M. Lloyd wrote:
> On 12/10/2014 09:52 AM, Brian Stansberry wrote:
>> On 12/10/14, 9:22 AM, Kabir Khan wrote:
>>>
>>>> On 9 Dec 2014, at 21:00, Brian Stansberry <brian.stansberry at redhat.com> wrote:
>>>>
>>>> Off and on we've had discussions around the idea of "attribute groups".
>>>> We've got some use cases that are crying out for such a thing[1], so I'd
>>>> like to propose doing something concrete but simple for these for WF 9,
>>>> ideally in the next month.
>>>>
>>>> A big part of my goal here is to ensure that whatever we do doesn't
>>>> preclude something more advanced in any next generation management
>>>> stuff, e.g. David's stuff.
>>>>
>>>> PART I Concepts
>>>>
>>>> 1) What is an attribute group?
>>>>
>>>> The "attribute group" concept I propose is simply a collection of
>>>> attributes associated with the same resource type that are independently
>>>> configurable but are statically declared to be conceptually related. The
>>>> group has a name, and members. The name provides a brief indication of
>>>> the nature of the relationship.
>>>>
>>>> The goal is to provide information to the user to help them better
>>>> understand the relationship between attributes. In particular,
>>>> management tools could use this information to visually present related
>>>> attributes together, e.g. in a tab or other grouping widget in the web
>>>> console.
>>>>
>>>> 2) What isn't an attribute group?
>>>>
>>>> Something relevant to writes.
>>>>
>>>> 3) Why would I use a child resource instead of an attribute group?
>>>>
>>>> Because the attributes control a discrete piece of functionality and you
>>>> need to be able to turn that on or off as a unit. So you add/remove the
>>>> resource.
>>>>
>>>> 4) Why would I use a complex attribute with a bunch of fields instead of
>>>> n>1 simple attributes in a group.
>>>>
>>>> a) Because the attributes control a discrete piece of functionality and
>>>> you need to be able to turn that off as a unit. So users can undefine
>>>> the complex attribute.
>>>>
>>>> b) Because it's a common use case that modifications to n>1 of the
>>>> fields should be done atomically and you don't want to force users to
>>>> use a CLI batch. So you let them use write-attribute and specify the
>>>> value of all the fields.
>>> Why not something along the lines of :write-attribute-group(name=mygroup, value={attr1=a, attr2=b})?
>>> Internally that could create a composite for us, giving complex attribute functionality while avoiding the messy resource descriptions
>>>
>>
>> On the branch of the thread where I'm discussing with Tomaz, he raised
>> the same idea, which I think is a good one. I think a "write-attributes"
>> with no relationship to attribute-group makes more sense though.
>
> I agree.  I have always felt that we should allow more than level of
> grouping.

Did you mean "should NOT allow"?

>  Having a special operation that "knows about" attribute
> groups in some special way is thus precluded; simply having a multiple
> "write-attributes" fits in nicely with the concept that a resource is
> actually our basic atomic unit of granularity.
>


-- 
Brian Stansberry
Senior Principal Software Engineer
JBoss by Red Hat