On Tue, 25 Sep 2012 08:04:39 +0000, "Feldhaus, Florian"

<florian.feldhaus@gwdg.de> wrote:

Dear all,

Andy and I had a discussion on IDs for OCCI Entities last week wether they

should be UUIDs and wether they have to be globally unique. In the

published version of OCCI Core, it states that entity IDs must be URIs and

"A unique identifier (within the service provider’s name- space) of the

Entity sub-type instance.". In 3.1 of the OCCI RESTful HTTP Rendering

document, it says:

"Each resource instance within an OCCI system MUST have a unique

identifier stored in the occi.core.id attribute of the Entity type [1]. It

is RECOMMENDED to use a Uniform Resource Name (URN) as the identifier

stored in occi.core.id.

The structure of these identifiers is opaque and the system should not

assume a static, pre-determined scheme for their structure. For example

occi.core.id could be urn:uuid:de7335a7-07e0-4487-9cbd-ed51be7f2ce4."

In my opinion it would be very good if both sentences could be moved to

OCCI Core to clarify the ID format. Thus we would stress the fact, that

UUIDs should be used, but we probably shouldn't require that they have to

be used. It is probably not necessary to enforce IDs to be globally unique,

but with UUIDs implementers can follow the guidelines in the RFC to ensure

global uniqueness.

+1

For the sake of backward compatibility I agree we probably cannot require
Entity.ID to be a UUID. A "SHOULD" is an acceptable compromise IMO.

Just to clarify, do you think that OCCI Core should recommend a specific
format of the Entity IDs as well?

I mean, even if Entity.ID is a UUID there are multiple ways to represent a
UUID. E.g. canonical form, binary format, URN, etc.

Having a specific ID format specified directly in OCCI Core would
definitely help with consistency across renderings. However from a
technical perspective I think the particular UUID format to use should be
up to the rendering.

regards, Ralf

Am 03.09.2012 um 19:01 schrieb Ralf Nyren:

Dear all,

I have update the Core document to include the changes discussed on the

last few confcalls.

The LaTeX changes are available from the core-errata branch in the

occi-wg

Git repository. Please find a compiled document attached.

Add a Attribute type to the Core Model

--------------------------------------

Many who have implemented the OCCI Core model already added an

Attribute

type. This change formalise the notion of "attribute properties".

Instead of just saying an attribute have a name, an attribute now has

its

on Attribute type with both name an properties.

The new Attribute type is an *identifier* for resource attributes. It

does

not contain the attribute value. I.e. just as before.

A distinction has been added between "client discoverable attributes"

(called OCCI Attributes) and attributes internal to the model (called

model

attributes). occi.core.id, occi.core.source and occi.core.target have

been

changed back to the model attributes they were until shortly before

HTTP

Rendering was released. These are determined to be model attributes and

thus receive special care in renderings.

Change Action to inherit Category

---------------------------------

The concept of Action representing the "invocable operation" itself is

removed. Instead an Action is just an *identifier* of the operation.

An Action instance identifies an invocable operation in much the same

way as a Kind instance identifies an Entity sub-type.

Impact on the existing HTTP Rendering (occi/1.1) is none. In fact the

text/ renderings already use "type=action" in its Category headers.

regards, Ralf<core.pdf>_______________________________________________

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