Re: [netmod] Fwd: Re: YANG schema mount - any early implementations?

Martin Bjorklund <mbj@tail-f.com> Mon, 06 August 2018 11:06 UTC

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Date: Mon, 06 Aug 2018 13:06:29 +0200 (CEST)
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Subject: Re: [netmod] Fwd: Re: YANG schema mount - any early implementations?
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Hi,

Hayden Brown <Hayden.Brown@Aviatnet.com>; wrote:
> ​Hi Lou,
> 
> 
> Thank you for your response. In the new copy of the sections below I've attempted to convey how I think the paragraphs could read.
> 
> 
> In my mind, the main "point of ambiguity" is that it seemed the existing wording implies:
> 
>   *   ​ the mount-point list specifies which modules are mounted below the root of the mount point.
> 
> however, I think we have all agreed that:
> 
>   *   ​the mo​unt-point list specifies the parent module that contains the mount-point,.
> 
> I see this as just a subtle interpretation difference in the wording "specifies the mounted schema".
> 
> 
> 
> Hopefully the wording (edited in the brackets) below better conveys my thoughts. Please feel free to correct me, or improve the wording below as you see fit.
> 
> Section 3.3 – Page 7
> > The "/schema-mounts" container has the "mount-point" list as one of its children. Every entry of this list refers through its key to a mount point and specifies the [type of] mounted schema [as "inline" or "shared-schema"].
> 
> Section 3.3 - Page 8
> > An entry of the "mount-point" list can specify the [type of] mounted schema in two different ways, "inline" or "shared-schema".

The document does not define the "type" of a mounted schema, so I
don't think we should use that term in just a few places.

> Section 9 - Page 13
> > A mount point defines a place in the node hierarchy where other data models may be attached. A server that implements a module with a mount point populates the /schema-mounts/mount-point list with detailed information on whether the [data models mounted at each instance of a mount point MAY be different ("inline" case) or MUST all have the same YANG library checksum ("shared-schema" case).
> 
> For a "shared-schema" mount-point list entry, the entry MAY include one or more "parent-reference" list entries that are used to specify the context nodeset for any XPath 1.0 expressions defined within the mounted schema.]
> 
> 
> Section 9 - Page 14
> list mount-point {
>     key "module label";
>     description
>     "Each entry of this list specifies [the type of] schema for a particular mount point [ ("inline" or "shared-schema") ].
> 
> 
> Thanks and best regards,
> 
> Hayden
> 


/martin



> 
> 
> 
> 
> ________________________________
> From: Lou Berger <lberger@labn.net>;
> Sent: Friday, 3 August 2018 7:28 a.m.
> To: Hayden Brown; netmod@ietf.org
> Subject: EXTERNAL: Re: [netmod] Fwd: Re: YANG schema mount - any early implementations?
> 
> 
> Hi,
> 
>     hopefully others will chime in too, but here's my view (as a user of schema mount, see https://tools.ietf.org/html/draft-ietf-rtgwg-ni-model)...
> 
> On 7/30/2018 7:27 PM, Hayden Brown wrote:
> 
> Hi everyone,
> 
> I just wanted to ask if it would be possible to clarify the intentions around some of the wording of the draft schema mount standard (Rev-10). In particular, regarding entries of the /schema-mounts/mount-points list.
> 
> My interpretation is that the intended use of the /schema-mounts/mount-points list entries are to specify the parent modules that contain a mount point.
> 
> yes
> 
> Following on from this, the client should use the YANG library instance to determine which schema options can be mounted at the root of a mount point. This seems consistent with the examples of Appendix A of the draft standard.
> 
> if you drop the word "options", then yes.  Other examples can be found in draft-ietf-rtgwg-ni-model
> 
> 
> In this email I wanted to highlight the following sections of the draft RFC below. In my view they seem to me to be somewhat ambiguous, in implying that the mount-point list entries specify the *child* module (sub-schema):
> 
> 
> >From https://datatracker.ietf.org/doc/draft-ietf-netmod-schema-mount/?include_text=1
> Section 3.3 – Page 7
> > The "/schema-mounts" container has the "mount-point" list as one of its children. Every entry of this list refers through its key to a mount point and specifies the mounted schema.
> 
> Section 3.3 - Page 8
> > An entry of the "mount-point" list can specify the mounted schema in two different ways, "inline" or "shared-schema".
> 
> 
> Section 9 - Page 13
> > A mount point defines a place in the node hierarchy where other data models may be attached. A server that implements a module with a mount point populates the /schema-mounts/mount-point list with detailed information on which data models are mounted at each mount point.
> 
> Section 9 - Page 14
> list mount-point {
>     key "module label";
>     description
>     "Each entry of this list specifies a schema for a particular mount point.
> 
> 
> I have reread the a few times and am having a hard time understand what should be changed.  Can you suggest specific changes that would address your concern/comment?  This might help to understand the issue you are seeing.
> 
> 
> The wording makes me wonder if these passages might actually just be "left-over" context from earlier revisions of the draft standard (Revision 8 and prior) -- effectively referring back to the schema-mount 'use-schema' list.
> 
> Again, I'm seeing the issue.
> 
> 
> I do of course acknowledge that it is entirely possible that I've misinterpreted the wording of the passages above, however if that is the case, I suspect I may not be the only one in future.
> And I'm sure I'm suffering from having spent way too much time on this topic so may be seeing things in the text that aren't actually there!
> 
> Cheers,
> Lou
> (no hats)
> 
> 
> Many thanks for your time on this matter.
> 
> Best regards,
> Hayden
> 
> 
> 
> 
> 
> 
> 
> On 20/07/2018 8:09 PM, Juergen Schoenwaelder wrote:
> 
> On Wed, Jul 11, 2018 at 09:43:32AM +1200, hayden wrote:
> 
> 
> 
> I understand that the schema mount proposal is still effectively in a
> 
> state of flux, but are there any publicly visible implementations or
> 
> deployments of a NETCONF or RESTCONF server that those interested could
> 
> experiment with (e.g. to aid in client development)?
> 
> 
> 
> State of flux? It is past WG last call and IETF last call.
> 
> 
> 
> https://datatracker.ietf.org/doc/draft-ietf-netmod-schema-mount/history/
> 
> 
> 
> /js
> 
> 
> 
> 
> 
> 
> 
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