Re: [netmod] Augmentation to Groupings

The restrictions and scopes might be defined, hopefully. It would also be ok to add new name.

Thanks,

- Xufeng

From: Andy Bierman [mailto:andy@yumaworks.com] 
Sent: Tuesday, December 19, 2017 3:01 PM
To: Alexander Clemm <alexander.clemm@huawei.com>
Cc: Juergen Schoenwaelder <j.schoenwaelder@jacobs-university.de>de>; Xufeng Liu <xufeng.liu.ietf@gmail.com>om>; NETMOD WG <netmod@ietf.org>
Subject: Re: [netmod] Augmentation to Groupings

Hi,

I do not want YANG to have augment for groupings because there is

no way to control all possible uses-stmts and make sure the augmentation

is only used where intended.  This seems no different than OO code.

A new class name is required for the derived class. In YANG a new grouping

is required and specific uses-stmts have to be updated to use the new grouping.

Andy

On Tue, Dec 19, 2017 at 11:51 AM, Alexander Clemm <alexander.clemm@huawei.com <mailto:alexander.clemm@huawei.com> > wrote:

IMHO it would be worth a try.  If you wanted to only augment _some_ uses of a grouping, you could still do the same as today.  Also, I would expect augmentations to only affect servers that support the module defining the augmentation.  If verbosity were not an issue, why were groupings introduced in the first place?
--- Alex

> -----Original Message-----
> From: netmod [mailto:netmod-bounces@ietf.org <mailto:netmod-bounces@ietf.org> ] On Behalf Of Juergen
> Schoenwaelder
> Sent: Tuesday, December 19, 2017 11:15 AM
> To: Xufeng Liu <xufeng.liu.ietf@gmail.com <mailto:xufeng.liu.ietf@gmail.com> >
> Cc: NETMOD WG <netmod@ietf.org <mailto:netmod@ietf.org> >
> Subject: Re: [netmod] Augmentation to Groupings
>
> The current approach may be verbose but it protects users of groupings from
> unwanted and uncontrolled side effects. Augmenting a grouping as
> suggested affects _all_ uses of a grouping; this can be tricky in situations
> where groupings are widely used.
>
> /js
>
> On Tue, Dec 19, 2017 at 11:45:06AM -0500, Xufeng Liu wrote:
> > During the discussions of TE tunnel and topology models, we have found
> > that it is desirable to have the capability of augmenting a grouping.
> >
> > In our case, there are multiple technology specific models augmenting
> > a base generic model. In the base model, some groupings are used
> > multiple times, and each augmentation model needs to add more schema
> > nodes to the grouping structure. For now, we have to specify an
> > “augment” statement for each location where the grouping is used. Such
> > an “augment” statement is repeated many times. It would be convenient
> > and cleaner if we could augment the grouping.
> >
> > We’d like to hear opinions on the feasibility of such a capability.
> >
> > Thanks,
> >
> > - Xufeng
>
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>
>
> --
> Juergen Schoenwaelder           Jacobs University Bremen gGmbH
> Phone: +49 421 200 3587         Campus Ring 1 | 28759 Bremen | Germany
> Fax:   +49 421 200 3103         <http://www.jacobs-university.de/>
>
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