Re: [netconf] YANG attributes in a datastore

Ladislav Lhotka <lhotka@nic.cz> wrote:
> On Tue, 2019-12-10 at 15:03 +0100, Martin Bjorklund wrote:
> > Hi,
> > 
> > Michal Vaško <mvasko@cesnet.cz> wrote:
> > > Hello,
> > > we are thinking about adding support for arbitrary attributes [1] in
> > > our YANG/NETCONF datastore. To my knowledge, only the representation
> > > in XML or JSON is defined and standardized but there are no guidelines
> > > for editing (CRUD) these attributes.
> > > 
> > > So, my question is a rather general one, regarding implementations
> > > that support editing these attributes, would you mind sharing some
> > > basic ideas or principles used? Or is this outside any consensus and
> > > each implementation is free to handle this completely in its own
> > > fashion? Thanks for any input.
> > 
> > I think this depends on the attribute defintion.  Some attributes are
> > read-only from the northbound's protocol point of view.  Internally in
> > the server you may need some API to set/change them of course.  Some
> > other attributes are read-write.
> > 
> > In our implementation we support a few read-write attributes (and some
> > read-only).  Here's a simple example (in an edit-config):
> > 
> >   <foo annotation="hello"/>
> > 
> > This would set/change the "annotation" attribute's value to
> > "hello", regardless of its previous value.
> > 
> > To delete an annotation, you would do:
> > 
> >   <foo annotation=""/>
> > 
> > Each of our attributes has a special value that means "delete" (in
> > most cases it is the empty string.
> 
> Hmm, why don't you do simply
> 
> <foo/>
> 
> to delete the attribute?

B/c that would mean that all attributes would have to be repeated just
to set a value; I don't want:

  <foo>42</foo>

to erase all attributes on foo.

/martin

> 
> Lada
> 
> > 
> > 
> > /martin
> > 
> > 
> > 
> > 
> > > Regards,
> > > Michal
> > > 
> > > [1] https://tools.ietf.org/html/rfc7952
> > > 
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> -- 
> Ladislav Lhotka
> Head, CZ.NIC Labs
> PGP Key ID: 0xB8F92B08A9F76C67
> 
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