[wildfly-dev] Management model attribute groups

[David M. Lloyd]

Forgot to hit "reply to list" on this one.

On 12/10/2014 10:30 AM, Brian Stansberry wrote:
> 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"?

No, I mean multiple levels _should_ be allowed, just with multiple 
qualifiers.  Multiple attribute writing per resource _should_ be allowed 
regardless of the depth or mixture of nesting.

I.e. I should be able to do something like :write-attributes({"foo" = 
123, "bar.baz.zap" = "hello"}) as one operation, with no special regard 
necessary to deal with attribute group navigation.

-- 
- DML