Re: [netmod] Schema-mount question: Augmentation to the Mounted Module

[Martin Bjorklund <[e-mail]>]

"Xufeng Liu" <[e-mail]> wrote:
> Hi Martin,
> 
> > -----Original Message-----
> > From: Martin Bjorklund [mailto:[e-mail]]
> > Sent: Wednesday, June 14, 2017 1:07 PM
> > To: [e-mail]
> > Cc: [e-mail]; [e-mail]; draft-ietf-netmod-schema-
> > [e-mail]; [e-mail]
> > Subject: Re: [netmod] Schema-mount question: Augmentation to the Mounted
> > Module
> > 
> > Ladislav Lhotka <[e-mail]> wrote:
> > >
> > > > On 14 Jun 2017, at 13:43, Lou Berger <[e-mail]> wrote:
> > > >
> > > > Hi,
> > > >
> > > > (speaking as contributor...)
> > > >
> > > >
> > > > On 6/14/2017 7:17 AM, Ladislav Lhotka wrote:
> > > >> Hi Xufeng,
> > > >>
> > > >> please see my answers inline.
> > > >>
> > > >> Xufeng Liu <[e-mail]> writes:
> > > >>
> > > >>> Hi Lada,
> > > >>>
> > > >>>
> > > >>>
> > > >>> We have got two questions on how to specify the module entries in
> > > >>> a
> > > >>> schema:
> > > >>>
> > > >>>
> > > >>>
> > > >>> 1. Are augmentations of parent modules inherited when augmented
> > > >>> module is listed in schema-mounts schema?
> > > >>>
> > > >>> For example, ietf-ospf module augments ietf-routing. When we
> > > >>> include ietf-routing to the schema entry, is ietf-ospf automatically
> > included?
> > > >> No, you also have to include "ietf-ospf" in the "module" list
> > > >> inside the corresponding "schema" entry, exactly as you do in the
> > > >> top level YANG library, otherwise ietf-ospf won't be mounted.
> > > >
> > > > I agree.  The draft should have text that makes this explicit.
> > >
> > > Why? It should be sufficiently clear that modules that are not listed
> > > in "schema" are not present in the mounted schema. An augment is just
> > > a special mechanism of contributing schema nodes.
> > 
> > Yes I agree.  But let's see if we can clarify the text.  Xufeng, what in
> the current
> > text led you to believe that a module in the parent schema would be
> > automatically present in the mounted schema?
> > 
> [Xufeng] Thanks for looking at this. The confusion is because of the lack of
> text, I would say. The term "mount" has an analogy to the Unix file system
> "mount", where what we only specify the parent directory and child file
> system (the connecting relationship at the connection point). Also, similar
> is the command for the Unix soft/hard links, where we don't need to check if
> there are other links under the child. 

I see.  Note that the analogy doesn't quite work, since there is no
requirement that the mounted module is even present in the parent
schema.  It has been suggested before that the term "mount" is
unfortunate...  Anyway, I think we can clarify that there is really no
relation between the parent schema and mounted modules, maybe like
this:

  The modules that are mounted under a mount point has no relation to
  the modules in the parent schema; specifically, if a module is
  mounted it may or may not be present in the parent schema.



/martin