Re: [netmod] yang-data-ext issues
Martin Bjorklund <mbj@tail-f.com> Tue, 24 April 2018 14:51 UTC
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Date: Tue, 24 Apr 2018 16:51:04 +0200
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To: rwilton@cisco.com
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From: Martin Bjorklund <mbj@tail-f.com>
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Subject: Re: [netmod] yang-data-ext issues
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Robert Wilton <rwilton@cisco.com> wrote: > > > On 23/04/2018 21:08, Martin Bjorklund wrote: > > Andy Bierman <andy@yumaworks.com> wrote: > >>> .... > >>>> I do not understand the need for a yang-data structure that represents > >>> data > >>>> that can be instantiated anywhere and everywhere. > >>> AFAIK noone is proposing that. > >>> > >>>> I do not want to break > >>>> existing tools that expect sibling data nodes in the same module > >>> namespace > >>>> to > >>>> be unique local-names. > >>>> > >>>> I would rather stick with the yang-data in RFC 8040 than introduce a > >>>> new > >>>> extension > >>>> with no restrictions. Standard YANG extensions should be > >>>> interoperable > >>> and > >>>> have > >>>> a clear purpose. > >>> Of course. > >>> > >>>> If we do not need to define what a YANG extension does in > >>>> a way that can be observed somehow, then it does not need to be a > >>> standard. > >>> > >>> Agreed. > >>> > >>> Not sure how any of this helps with the original issue though. > >>> > >>> > >> You proposed that duplicate nodes were OK: > >> > >> module X { > >> prefix x; > >> > >> x:yang-data A { > >> list foo { ... } > >> } > >> > >> x:yang-data B { > >> container foo { ... } > >> } > >> > >> } > >> > >> > >> I do not want to allow any duplicates. > > Yes, I got that. > > > >> There are no encoding and parsing rules for instance data > >> that support this sort of duplicate. > > This is not correct, as I have demonstrated earlier, and I think you > > also accepted; if different structures are defined for different rpcs' > > error-infos, then these structures can have the same child node names. > > > > I think that we have to agree on the basics before disussing > > solutions: > > > > 1) Should we do anything at all? > > > > (i.e., keep using yang-data in RFC 8040) > There is also an option 1(b) which is to move the current yang-data > definition on RFC 8040 into it's own document, just to fix the > references issue. Sure, but I don't think it is worth the effort. > > 2) Should we define structures that only can be used in > > standalone instance documents? > > > > (i.e., *more* restrictive than yang-data in RFC 8040) > I don't think that we should define something more restrictive that > yang-data in RFC 8040. I agree. > > 3) Should we define structures that can be used in standalone > > instance documents, error-info contents, and other places that > > we might not know right now? > > > > (i.e., *less* restrictive than yang-data in RFC 8040) > I don't know about this one because I'm not sure that I understand the > problem space well enough. > > For some of the categories above would a choice statement + groupings > works just as well as a yang-data extension? Not sure what you mean, but before we had yang-data in 8040, people used something like this: module my-module { .... container foo { description "This is not really a real data node that is supposed to be instantiated in any datastore. Instead it is supposed to be the top-level node in an instance document that describes..."; } } By this is really a mis-use of YANG statements. Wrapping it in an extension solves that problem. > A different thought, one that has probably been considered before: > - Could all yang data definitions be defined using groupings > instead. I.e. a grouping without any associated uses statements. > - Perhaps an extra statement under the grouping could be used to > indicate whether the grouping represents a yang data definition. Nodes in a grouping do not belong to any namespace. Forcing such a namespace binding with a substatement to "grouping" feels worse than having a YANG extension with the nodes defined (which of course can be done with "uses"). /martin > > Thanks, > Rob > > > > > > > > Since the current draft says: > > > > The "yang-data" extension statement from RFC > > 8040 [RFC8040] is defined for this purpose, however it is limited in > > its functionality. > > > > The intended use of the "yang-data" extension is to model all or part > > of a protocol message, such as the "errors" definition in ietf- > > restconf.yang [RFC8040], or the contents of a file. However, > > protocols are often layered such that the header or payload portions > > of the message can be extended by external documents. The YANG > > statements that model a protocol need to support this extensibility > > that is already found in that protocol. > > > > > > I thought we are doing (3). > > > > > > > > /martin > > > > > > > >> yang-data definitions define conceptual data nodes (e.g, /x:foo) > >> Only one data-def-stmt (in yang-data or otherwise) can define a data > >> node > >> /x:foo. > >> The descriptive names for the yang-data (A or B) do not define > >> namespaces. > >> > >> > >> > >>> /martin > >>> > >>> > >> Andy > > _______________________________________________ > > netmod mailing list > > netmod@ietf.org > > https://www.ietf.org/mailman/listinfo/netmod > > . > > >
- Re: [netmod] yang-data-ext issues Kent Watsen
- Re: [netmod] yang-data-ext issues Joe Clarke
- Re: [netmod] yang-data-ext issues Kent Watsen
- [netmod] yang-data-ext issues Martin Bjorklund
- Re: [netmod] yang-data-ext issues Joe Clarke
- Re: [netmod] yang-data-ext issues Andy Bierman
- Re: [netmod] yang-data-ext issues Martin Bjorklund
- Re: [netmod] yang-data-ext issues Martin Bjorklund
- Re: [netmod] yang-data-ext issues Andy Bierman
- Re: [netmod] yang-data-ext issues Robert Wilton
- Re: [netmod] yang-data-ext issues Andy Bierman
- Re: [netmod] yang-data-ext issues Martin Bjorklund
- Re: [netmod] yang-data-ext issues Robert Wilton
- Re: [netmod] yang-data-ext issues Andy Bierman
- Re: [netmod] yang-data-ext issues Ladislav Lhotka
- Re: [netmod] yang-data-ext issues Kent Watsen
- Re: [netmod] yang-data-ext issues Martin Bjorklund
- Re: [netmod] yang-data-ext issues Andy Bierman
- Re: [netmod] yang-data-ext issues Martin Bjorklund
- Re: [netmod] yang-data-ext issues Andy Bierman
- Re: [netmod] yang-data-ext issues Kent Watsen
- Re: [netmod] yang-data-ext issues Robert Varga
- Re: [netmod] yang-data-ext issues Ladislav Lhotka
- Re: [netmod] yang-data-ext issues Martin Bjorklund
- Re: [netmod] yang-data-ext issues Andy Bierman
- Re: [netmod] yang-data-ext issues Martin Bjorklund
- Re: [netmod] yang-data-ext issues Andy Bierman
- Re: [netmod] yang-data-ext issues Robert Varga
- Re: [netmod] yang-data-ext issues Juergen Schoenwaelder
- Re: [netmod] yang-data-ext issues Robert Varga
- Re: [netmod] yang-data-ext issues Juergen Schoenwaelder
- Re: [netmod] yang-data-ext issues Martin Bjorklund
- Re: [netmod] yang-data-ext issues Martin Bjorklund
- Re: [netmod] yang-data-ext issues Andy Bierman
- Re: [netmod] yang-data-ext issues Martin Bjorklund
- Re: [netmod] yang-data-ext issues Andy Bierman
- [netmod] Extensions vs new YANG versions [was Re:… Robert Wilton
- Re: [netmod] yang-data-ext issues Robert Wilton
- Re: [netmod] Extensions vs new YANG versions [was… Ladislav Lhotka
- Re: [netmod] yang-data-ext issues Ladislav Lhotka
- Re: [netmod] yang-data-ext issues Ladislav Lhotka
- Re: [netmod] yang-data-ext issues Martin Bjorklund
- Re: [netmod] yang-data-ext issues Martin Bjorklund
- Re: [netmod] yang-data-ext issues Martin Bjorklund
- Re: [netmod] yang-data-ext issues Ladislav Lhotka
- Re: [netmod] yang-data-ext issues Andy Bierman
- Re: [netmod] yang-data-ext issues Kent Watsen
- Re: [netmod] yang-data-ext issues Martin Bjorklund
- Re: [netmod] yang-data-ext issues Martin Bjorklund
- Re: [netmod] yang-data-ext issues Andy Bierman
- Re: [netmod] yang-data-ext issues Andy Bierman
- Re: [netmod] yang-data-ext issues Ladislav Lhotka
- Re: [netmod] yang-data-ext issues Juergen Schoenwaelder
- Re: [netmod] yang-data-ext issues Ladislav Lhotka
- Re: [netmod] yang-data-ext issues Andy Bierman
- Re: [netmod] yang-data-ext issues Ladislav Lhotka
- Re: [netmod] yang-data-ext issues Ladislav Lhotka
- Re: [netmod] yang-data-ext issues Andy Bierman
- Re: [netmod] yang-data-ext issues Ladislav Lhotka
- Re: [netmod] yang-data-ext issues Martin Bjorklund
- Re: [netmod] yang-data-ext issues Robert Wilton
- Re: [netmod] yang-data-ext issues Ladislav Lhotka
- Re: [netmod] yang-data-ext issues Robert Wilton
- Re: [netmod] yang-data-ext issues Ladislav Lhotka
- Re: [netmod] yang-data-ext issues Juergen Schoenwaelder
- Re: [netmod] yang-data-ext issues Ladislav Lhotka
- Re: [netmod] yang-data-ext issues Andy Bierman
- Re: [netmod] yang-data-ext issues Juergen Schoenwaelder
- Re: [netmod] yang-data-ext issues Ladislav Lhotka
- Re: [netmod] yang-data-ext issues Kent Watsen
- Re: [netmod] yang-data-ext issues Andy Bierman
- Re: [netmod] yang-data-ext issues Kent Watsen
- Re: [netmod] yang-data-ext issues Juergen Schoenwaelder
- Re: [netmod] yang-data-ext issues Kent Watsen
- Re: [netmod] yang-data-ext issues Juergen Schoenwaelder
- Re: [netmod] yang-data-ext issues Martin Bjorklund
- Re: [netmod] yang-data-ext issues Ladislav Lhotka
- Re: [netmod] yang-data-ext issues Martin Bjorklund
- Re: [netmod] yang-data-ext issues Martin Bjorklund
- Re: [netmod] yang-data-ext issues Martin Bjorklund
- Re: [netmod] yang-data-ext issues Ladislav Lhotka
- Re: [netmod] yang-data-ext issues Martin Bjorklund
- Re: [netmod] yang-data-ext issues Robert Wilton
- Re: [netmod] yang-data-ext issues Martin Bjorklund
- Re: [netmod] yang-data-ext issues Juergen Schoenwaelder
- Re: [netmod] yang-data-ext issues Ladislav Lhotka
- Re: [netmod] yang-data-ext issues Robert Varga
- Re: [netmod] yang-data-ext issues Robert Varga
- Re: [netmod] yang-data-ext issues Kent Watsen
- Re: [netmod] yang-data-ext issues Juergen Schoenwaelder
- Re: [netmod] yang-data-ext issues Andy Bierman
- Re: [netmod] yang-data-ext issues Kent Watsen
- Re: [netmod] yang-data-ext issues Ladislav Lhotka