Re: [netmod] status-description

[Martin Björklund <[e-mail]>]

"Reshad Rahman (rrahman)" <[e-mail]> wrote:
> What are your thoughts on having description statement under status in
> yang-next?

No problem!  In fact, "description" could be allowed under _any_
statement...


/martin


> Is it the same as what you’ve stated on status-description
> extension?
> 
> I believe the extension is useful, although I do see the point made
> that an extra statement leads to extra complexity. But using
> description statement in yang-next should not be an issue?
> 
> Regards,
> Reshad.
> 
> From: 'Andy Bierman' <[e-mail]>
> Date: Monday, May 4, 2020 at 1:32 PM
> To: Martin Björklund <[e-mail]>
> Cc: Balazs Lengyel <[e-mail]>, "Reshad Rahman
> (rrahman)" <[e-mail]>, NetMod WG <[e-mail]>
> Subject: Re: [netmod] status-description
> 
> 
> 
> On Mon, May 4, 2020 at 9:38 AM Martin Björklund
> <[e-mail]<mailto:[e-mail]>> wrote:
> Hi,
> 
> Balázs Lengyel
> <[e-mail]<mailto:[e-mail]>>
> wrote:
> > Hello,
> > While status-description is not a critical part of this work, it is
> > still useful, does not harm and is such a small addition, I do not
> > understand why Martin objects.
> 
> Every additional statement adds to the overall complexity.  As Jason
> explained, this particular statement doesn't really help much.
> 
> 
> +1
> 
> We should not start down the path of specialized description
> statements.
> 
> I was part of a design team many years ago that was trying to
> figure out why engineers were having so much trouble writing MIB
> modules.
> One significant finding: people disliked working on MIBs because there
> were so
> many special little rules (CLRs) for every little detail in the
> module.
> 
> IMO we are starting to make the same mistake with YANG.
> 
> 
> /martin
> 
> Andy
> 
> 
> >
> > So why is status-description good:
> > Sometimes additional information is needed about deprecation,
> > obsolescence:
> > - is the item still fully functional?
> > - when will its functionality be removed?
> > - when will the schema node itself be removed?
> > - is there a replacement or workaround that could/should be used instead
> > - of deprecated/obsolete item?
> > The text can be used by tools. Using a separate statement to provide
> > this
> > information is a method to separate the main description from this
> > status specific description.
> > In most cases both in the CLI and on NMS GUIs only the description is
> > displayed.
> > However there is a possibility  to display the status information too.
> >
> > In a way it is similar why we have separate description, contact,
> > reference, organization statements under module.
> > All these are just text, they could all be pushed under a single
> > description statement. Tools can't act on these automatically, still
> > it is good to separate them.
> >
> > Regards Balazs
> >
> > -----Original Message-----
> > From: netmod <[e-mail]<mailto:[e-mail]>>
> > On Behalf Of Sterne, Jason
> > (Nokia - CA/Ottawa)
> > Sent: 2020. április 29., szerda 23:38
> > To: Reshad Rahman (rrahman)
> > <rrahman=[e-mail]<mailto:[e-mail]>>;
> > Martin Björklund <[e-mail]<mailto:[e-mail]>>;
> > [e-mail]<mailto:[e-mail]>
> > Subject: Re: [netmod] status-description (WAS Re: mbj review of
> > draft-verdt-netmod-yang-module-versioning-01)
> >
> > I think we could wait until YANG 2.0 to add a description to the
> > status.
> >
> > Without a status description, an intelligent "YANG diff" of the models
> > would produce this:
> > a) new status deprecated statement
> > b) change to a description
> >
> > With a status description we'd identify this:
> > a) new status deprecated statement
> > b) new status description
> >
> > In both cases it is (a) that identifies the most clear information.
> >
> > In both cases (b) provides no additional information that can be acted
> > upon in an automated fashion. The tool could only flag that (b)
> > occurred in both cases and a human would then have to go look at it.
> >
> > If the only change between two versions of a module was a status
> > description change, then again a human would have to take a look. If
> > we add some sort of "nbc" tag to the leaf for tooling, then it also
> > doesn't matter which description changed.
> >
> > Jason
> >
> >
> > > -----Original Message-----
> > > From: netmod <[e-mail]<mailto:[e-mail]>>
> > > On Behalf Of Reshad Rahman
> > > (rrahman)
> > > Sent: Friday, March 27, 2020 5:43 PM
> > > To: Martin Björklund <[e-mail]<mailto:[e-mail]>>;
> > > [e-mail]<mailto:[e-mail]>
> > > Subject: [netmod] rev:status-description (WAS Re: mbj review of
> > > draft-verdt-
> > > netmod-yang-module-versioning-01)
> > >
> > > Hi,
> > >
> > > https://github.com/netmod-wg/yang-ver-dt/issues/51
> > >
> > >         o  3.4
> > >
> > >              leaf imperial-temperature {
> > >                type int64;
> > >                units "degrees Fahrenheit";
> > >                status deprecated {
> > >                  rev:status-description
> > >                    "Imperial measurements are being phased out in favor
> > >                     of their metric equivalents.  Use metric-temperature
> > >                     instead.";
> > >                }
> > >                description
> > >                  "Temperature in degrees Fahrenheit.";
> > >              }
> > >
> > >           I don't think rev:status-description is necessary / worth it.
> > >           This
> > >           can easily be written with the normal description statement
> > >           instead:
> > >
> > >              leaf imperial-temperature {
> > >                type int64;
> > >                units "degrees Fahrenheit";
> > >                status deprecated;
> > >                description
> > >                    "Imperial measurements are being phased out in favor
> > >                     of their metric equivalents.  Use metric-temperature
> > >                     instead.
> > >
> > >                     Temperature in degrees Fahrenheit.";
> > >              }
> > >
> > > While rev:status-description isn't strictly necessary, without it we'd
> > > have to modify the node's description as you pointed out. That'd make
> > > tooling more
> > > difficult: is the description change BC or NBC? Also, a user looking
> > > at a diff would need to go through the description change. Use of
> > > rev:status- description makes this easier to handle.
> > >
> > > Regards,
> > > Reshad.
> > >
> > >
> > >
> > > On 2020-03-20, 5:08 PM, "netmod on behalf of Reshad Rahman (rrahman)"
> > > <[e-mail]<mailto:[e-mail]> on behalf of
> > > rrahman=[e-mail]<mailto:[e-mail]>>
> > > wrote:
> > >
> > >     Hi Martin,
> > >
> > >     We've opened issues to track your review comments (see below).
> > > Will kick off separate therads for each issue.
> > >
> > >     https://github.com/netmod-wg/yang-ver-
> > > dt/issues?q=is%3Aissue+is%3Aopen+label%3Aupdated-mod-rev-handling
> > >
> > >     Regards,
> > >     Reshad.
> > >
> > >     On 2020-03-10, 3:31 PM, "netmod on behalf of Martin Björklund"
> > > <netmod- [e-mail]<mailto:[e-mail]> on behalf of
> > > [e-mail]<mailto:[e-mail]>> wrote:
> > >
> > >         Hi,
> > >
> > >         Here are my review comments of
> > >         draft-verdt-netmod-yang-module-versioning-01.
> > >
> > >
> > >
> > >         o  3.1.1
> > >
> > >             o  In statements that have any data definition statements as
> > >                substatements, those data definition substatements MAY be
> > >                reordered, as long as they do not change the ordering or any
> > >                "rpc"
> > >                "input" substatements.
> > >
> > >           I think this needs to capture that no descendant statements to
> > >           "input" can be reordered.  Same for "output" (note, "input" and
> > >           "output" in both "rpc" and "action").
> > >
> > >
> > >         o  3.3
> > >
> > >             All revision labels that match the pattern for the "version"
> > >             typedef in the ietf-yang-semver YANG module MUST be interpreted
> > >             as
> > >             YANG semantic version numbers.
> > >
> > >           I don't think this is a good idea.  Seems like a layer violation.
> > >           What if my project use another dialect of semver, that wouldn't
> > >           be
> > >           possible with this rule.  I think this needs to be removed.
> > >
> > >
> > >         o  3.3
> > >
> > >             Submodules MUST NOT use revision label schemes that could
> > > be confused
> > >             with the including module's revision label scheme.
> > >
> > >           Hmm, how do I ensure that this MUST NOT is handled correctly?
> > >           What
> > >           exactly does "could be confused with" mean?
> > >
> > >
> > >         o  3.3
> > >
> > >               In the filename of a YANG module, where it takes the form:
> > >               module-
> > >               or-submodule-name ['@' revision-label] ( '.yang' /
> > > '.yin' )
> > >
> > >           Should this section update 5.2 of RFC 7950?  I know that 5.2 just
> > >           says "SHOULD".  But existing tools implement this SHOULD, and
> > >           they
> > >           need to be updated to handle this new convention.
> > >
> > >           But I wonder if this a good idea.  It means that a tool that
> > >           looks
> > >           for a module with a certain revision date cannot simply check the
> > >           filenames, but need to parse all available modules (wijust
> > > to find the
> > >
> > >
> > >
> > >         o  3.4
> > >
> > >              leaf imperial-temperature {
> > >                type int64;
> > >                units "degrees Fahrenheit";
> > >                status deprecated {
> > >                  rev:status-description
> > >                    "Imperial measurements are being phased out in favor
> > >                     of their metric equivalents.  Use metric-temperature
> > >                     instead.";
> > >                }
> > >                description
> > >                  "Temperature in degrees Fahrenheit.";
> > >              }
> > >
> > >           I don't think rev:status-description is necessary / worth it.
> > >           This
> > >           can easily be written with the normal description statement
> > >           instead:
> > >
> > >              leaf imperial-temperature {
> > >                type int64;
> > >                units "degrees Fahrenheit";
> > >                status deprecated;
> > >                description
> > >                    "Imperial measurements are being phased out in favor
> > >                     of their metric equivalents.  Use metric-temperature
> > >                     instead.
> > >
> > >                     Temperature in degrees Fahrenheit.";
> > >              }
> > >
> > >
> > >         o  3.5
> > >
> > >           The example modules should be legal YANG modules.  Use e.g.
> > >           "urn:example:module" as namespace.
> > >
> > >           Also, the modules are missing the last "}", which confuses the
> > >           "rfcstrip" tool..
> > >
> > >
> > >         o 4.1.1
> > >
> > >             Alternatively, the first example could have used the revision
> > >             label
> > >             "1.0.0" instead, which selects the same set of
> > >             revisions/versions..
> > >
> > >             import example-module {
> > >               rev:revision-or-derived 1.0.0;
> > >             }
> > >
> > >           Shouldn't this be s/1..0.0/2.0.0/g ?
> > >
> > >
> > >         o  5
> > >
> > >           I think the module name "ietf-yl-revisions" should be changed to
> > >           "ietf-yang-library-revisions".  "yl" is not a well-known acronym.
> > >
> > >
> > >         o  5.2.2
> > >
> > >           Wouldn't it be better if the leaf "deprecated-nodes-implemented"
> > >           and
> > >           "obsolete-nodes-absent" were of type "boolean" rather than type
> > >           "empty"?
> > >
> > >
> > >         o  7.1
> > >
> > >           The text says:
> > >
> > >             All IETF YANG modules MUST include revision-label statements
> > >             for
> > >             all
> > >             newly published YANG modules, and all newly published revisions
> > >             of
> > >             existing YANG modules.  The revision-label MUST take the form
> > >             of
> > >             a
> > >             YANG semantic version number [I-D.verdt-netmod-yang-semver].
> > >
> > >           I strongly disagree with this new rule.  IETF modules use a
> > >           linear
> > >           history, so there are no reasons to use "modified semver".
> > >
> > >           It is ok to use rev:nbc-changes if needed, though.
> > >
> > >
> > >         o 7.1.1
> > >
> > >           There is a missing " in:
> > >
> > >            4.  For status "obsolete", it is RECOMMENDED to keep the
> > >            "status-
> > >                description" information, from when the node had status
> > >                "deprecated, which is still relevant.
> > >          HERE  -----------^
> > >
> > >
> > >         o  8
> > >
> > >           s/CODE ENDS>/<CODE ENDS>/
> > >
> > >
> > >         o Both YANG modules
> > >
> > >           All extensions should specify the grammar; i.e., in which
> > >           statements
> > >           they can be present and which substatements they can have.
> > >
> > >
> > >
> > >         /martin
> > >
> > >         _______________________________________________
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> > >
> > >
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