Re: [netmod] How to constrain a leaf to a read-only list of supported values?

"Dale R. Worley" <worley@ariadne.com> writes:

> Balazs Lengyel <balazs.lengyel@ericsson.com> writes:
>> Problem: how do you restrict values for (3) - file-compression so that 
>> it is one of the nodes-supported-compression-types. The natural solution 
>> would be to use a must expression or a leaf-ref, but as 
>> nodes-supported-compression-types is config-false data, it is not 
>> allowed to constrain the config=true leaf, file-compression, with it.
>
> I'm no expert at this, but it seems to me that the way to do it is to
> have the overall data structure be config-true but make the contained
> supported-compression-types be config-false.  You can nest config-false
> nodes in a config-true structure.  The Yang would be something like
> this:
>
> typedef Compression-Method {
>   ...
> }
>
> list node {
>   config true;
>   key name;
>
>   string name;
>
>   leaf-list supported-compression-methods {
>     type Compression-Method;
>     config false;
>   }
>
>   Compression-Method compression-method;
>   must "compression-method ... supported-compression-methods";
> }

I think this is a good idea. It would have to be done on ad hoc basis
but, on the other hand, not all enumerations permit implementations to
choose a subset of enums.

The only technical problem with your mock-up is that "must" expressions
on config nodes cannot refer to state data.

Lada

>
> Dale
>
> _______________________________________________
> netmod mailing list
> netmod@ietf.org
> https://www.ietf.org/mailman/listinfo/netmod

-- 
Ladislav Lhotka, CZ.NIC Labs
PGP Key ID: E74E8C0C