Re: [netmod] Proposal to enhance the YANG tree output

Robert Wilton <rwilton@cisco.com> Tue, 19 September 2017 13:39 UTC

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To: Lou Berger <lberger@labn.net>, Martin Bjorklund <mbj@tail-f.com>
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References: <5b512435-cebd-3534-eeb3-649154450d81@cisco.com> <20170915.134007.262763963470255554.mbj@tail-f.com> <c5352dde-4026-7549-bafa-30b19d7bb789@labn.net> <20170919.132947.358857445863848356.mbj@tail-f.com> <990b8722-7a48-46ce-3f5d-96bc5cb66075@labn.net>
From: Robert Wilton <rwilton@cisco.com>
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Date: Tue, 19 Sep 2017 14:39:16 +0100
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Subject: Re: [netmod] Proposal to enhance the YANG tree output
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On 19/09/2017 14:28, Lou Berger wrote:
>
> On 9/19/2017 7:29 AM, Martin Bjorklund wrote:
>> Lou Berger <lberger@labn.net> wrote:
>>> Martin,
>>>
>>> Speaking as a contributor:
>>>
>>>
>>> On 9/15/2017 7:40 AM, Martin Bjorklund wrote:
>>>> Robert Wilton <rwilton@cisco.com> wrote:
>>>>> On 15/09/2017 11:21, Ladislav Lhotka wrote:
>>>>>> Andy Bierman píše v Čt 14. 09. 2017 v 08:43 -0700:
>>>>>>> Hi,
>>>>>>>
>>>>>>>
>>>>>>> Actually I liked the early pyang output that was concise and easy to
>>>>>>> remember.
>>>>>>> The current format gets very cluttered and there are too many little
>>>>>>> symbols
>>>>>>> to remember them all.
>>>>>> I agree.
>>>> Me too.  The current draft adds three new magic symbols: "mp" "@" and
>>>> "/".
>>>>
>>>> "mp" is for a mount point, and it can be generated directly from the
>>>> YANG modules.
>>>>
>>>> Directly under a "mp", "/" and "@" are used to indicate that a node is mounted
>>>> or available through a parent reference, respectively.
>>>>
>>>> I actually question the usability of "/" and "@".
>>> I agree that / and @ are something new, and enabled by schema mount.
>>> There have been repeated comments in the RTG WG that there needs to be
>>> some way for vendors to convey what they have implemented with Schema
>>> mount
>> If that's the requirement, using the tree diagram is probably not the
>> best way.  The tree diagram is intended to provide an overview of a
>> given (set of) YANG module(s).
>>
>> A perhaps better way to convey the information is to create a file
>> with an instantiated /schema-mounts tree.
> using what syntax?  JSON and XML really isn't that easy for the (human)
> reader to parse.
Perhaps there needs to be multiple versions of the generated tree output?

1) A normative tree diagram that shows the structure of the model.
2) A subsequent example that demonstrates what it looks like with the 
schema mounted modules.  Within the confines of a text document, the 
tree format still seems like a reasonable way to illustrate this, and I 
would say it is preferable to the verbosity of JSON or XML.

I note that RFC 8022 includes an overview tree model in section 4 with 
some branches pruned, and then the complete representation in an 
appendix, which seems like a pragmatic approach.

Thanks,
Rob