[wildfly-dev] Management model attribute groups

[Heiko Braun]

Changing group names is not user space Api. Users can map internal names to custom titles, if needed.




> Am 10.12.2014 um 10:59 schrieb Emmanuel Hugonnet <ehugonne at redhat.com>:
> 
> Maybe we should also group attributes by their attribute group names instead of displaying them per natural sorting ?
> Is aliasing to be supported ?  What if I want to change the attribute group name ?
> 
> Emmanuel
> 
> 
> Le 09/12/2014 21:00, Brian Stansberry a écrit :
>> 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.
>> 
>> 5) Why would I use an attribute group instead of a child resource?
>> 
>> Because requiring users to add a child resource just to set a bunch of 
>> values that are really part of the config of the parent resource forces 
>> them to use a CLI batch to correctly configure the parent resource.
>> 
>> 6) Why would I use an attribute group instead a complex attribute?
>> 
>> Because the various attributes should be independently configurable. In 
>> particular, wiping out the config for all of them by simply undefining 
>> the complex attribute isn't appropriate.
>> 
>> PART II Proposed Work
>> 
>> 1) The basics
>> 
>> We add a piece of metadata to the read-resource-description output for 
>> an attribute. Name is 'attribute-group', value type is ModelType.STRING, 
>> value is the name of the group, with 'undefined' allowed.
>> 
>> The group is simply the set of attributes that share the same string.
>> 
>> To implement this, we add public String 
>> AttributeDefinition.getAttributeGroup() and add support for setting it 
>> to the relevant Builder. ReadResourceDescriptionHandler outputs the value.
>> 
>> 2) XML parsing/marshalling
>> 
>> Modify PersistentResourceXMLDescription such that attributes in an 
>> attribute group get persisted in their own child element, whose name is 
>> the name of the group.
>> 
>> PersistentResourceXMLBuilder exposes a setter to allow users to turn 
>> this on/off for that resource. Turning it off will allow the addition of 
>> attribute group settings for a resource without requiring an immediate 
>> corresponding xsd change.
>> 
>> 3) Web console
>> 
>> HAL can make use of the additional metadata at its leisure, and as it 
>> becomes available.
>> 
>> 4) Low level management API
>> 
>> The output of read-resource and read-resource-description is modified 
>> such that attributes are sorted by group name and then by attribute name.
>> 
>> 5) CLI
>> 
>> I'm not clear on exactly what to do here, but my instinct is the output 
>> of the 'ls -l' command should be modified. Probably add a GROUP column 
>> to the right and sort the order of attributes by group and then by 
>> attribute name.
>> 
>> PART III Other possible things to do
>> 
>> A :read-attribute-group(name=<groupname>) operation or an 
>> "attribute-groups=[<groupname>*]" param to :read-resource, to make it 
>> convenient to read a set of attributes without needing to read the 
>> entire resource.
>> 
>> We could also consider adding an "attribute-groups" section to the 
>> read-resource-description output, where a fuller i18n text description 
>> of the meaning of the group could be written. If we do this we should 
>> probably do it in WF 9 as it will likely add some sort of requirement to 
>> subsystem authors that we expose right from the start.
>> 
>> 
>> If you're still awake, comments as always are appreciated.
> 
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