[core] Re: Additional CORECONF Comments

[Andy Bierman <[e-mail]>]

On Thu, Jan 15, 2026 at 9:48 AM Vojtech Vilimek
<vojtech.vilimek=[e-mail]> wrote:
>
> Hi all,
>
> I found a crucial bug in the CORECONF: You can discover all the schema
> nodes of given model in the yang-library or .well-known/core but how do
> you discover instances of a list? For example in the following YANG model.
>


I think the WG decided not to support this feature.
IMO not a crucial bug.

> module list-inst {
>    prefix t;
>    namespace "http://example.com";
>
>    list instance {
>      key "name";
>
>      leaf "name" { type string; }
>      leaf "value" { type uint32; }
>    }
> }
>
> How do you discover existence of let's say instance with name "hidden"
> (i.e. "/list-inst:instance[name="hidden"]" 'instance-identifier')? You
> can use a GET method but the overhead for non-trivial YANG models is
> going to kill any reasonable real-world usage (IMHO). The overhead is
> huge because the GET will send the whole datastore (meaning all
> available instance data nodes).
>
> Also note that "/list-inst:instance" is not valid 'instance-identifier'
> as it does not encode all list keys. The exactly same problem is with
> using SIDs but less human readable. The only thing that changes is
> instead of "/list-inst:instance" we use SID like 60,000.
>
> I find that the protocol should be extended with ability to enumerate
> list instances and ability to get length of the instance list (and
> leaf-lists).
>
> Just that I am curious, how is this done in RESTCONF?
>

RESTCONF has the 'fields' query parameter to select specific child
nodes from each list entry.
https://datatracker.ietf.org/doc/html/rfc8040#section-4.8.3

NETCONF has subtree filters to do the same thing.

>
> Best regards,
>
> Vojtech Vilimek
> CZ.NIC z.s.p.o.
> Czech Republic
>


Andy

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