Re: [netmod] Fwd: New Version Notification for draft-ietf-netmod-yang-instance-file-format-01.txt

[Martin Bjorklund <[e-mail]>]

Juergen Schoenwaelder <[e-mail]> wrote:
> On Thu, Dec 06, 2018 at 10:15:30AM +0000, Balázs Lengyel wrote:
> > 
> >    Jürgen stated that it would be better to use the YANG XML/JSON encoding as
> >    a format instead of referencing the get operation/request. I might even
> >    agree with him, but for 2 reasons I did not follow his idea:
> > 
> >      * Currently there is no RFC I could reference either for XML or JSON.
> >        AFAIK even RFC7951 does not define how multiple modules should be
> >        encoded side by side.
> >      * It is not the job of the instance data draft to dictate how to encode
> >        YANG data generally e.g. on the wire.
> >      * The contents of the get operation/request are well defined
> >
> 
> The first bullet needs to be taken care of but it is not too difficult
> I think.
> 
> I fail to understand what bullet two is about or why it matters. We
> are talking about the instance file format, no more and no less.
> 
> Yes, the contents of the get operation/request are well defined but
> the definitions are not generically applicable to define instance file
> formats and the dependincy of the instance file format on protocols
> is problematic from a maintenance perspective.

I agree.

I'm not even convinced that the current text is clear and correct:

   The content-data part of the XML format SHALL follow the format
   returned for a NETCONF GET operation.  The <content-data> anydata
   node SHALL contain all elements that would be inside the <data>
   wrapper element of a reply to the <get> operation.

What exactly does "all elements that would be inside the <data>" mean?
Does it mean that if a server supports 10 modules, all 10 modules
MUST be part of all instance files?  Probably not.


Since the "content-data" is of type "anydata", I think that we don't
need much additional text.  Maybe something like:

   The "content-data" part may contain data from multiple modules, in
   any order.  For any node in "content-data", the path from the data
   model root node down to the node, including any elements
   necessary to uniquely identify the node, is included in the
   response message.



/martin