Re: [netconf] YANG attributes in a datastore

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?

Lada

> 
> 
> /martin
> 
> 
> 
> 
> > Regards,
> > Michal
> > 
> > [1] https://tools.ietf.org/html/rfc7952
> > 
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Ladislav Lhotka
Head, CZ.NIC Labs
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