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

[Vladimir Vassilev <[e-mail]>]

On 08/31/2016 01:10 PM, Balazs Lengyel wrote:
> Hello,
>
> The problem is not just about identities. It can be a value range.
If your example was about value range then a deviation would be a 
solution. Then we have the same case for modularization. YANG files 
defining deviations loaded when the deviation is relevant and not loaded 
otherwise.
> Sometimes we have a generic module like iana-interface type that list 
> a lot of identities, and I don't want to have one YAM file per 
> identity, to allow a fine control. Also sadly it is not possible to 
> have a deviation removing identities. IMHO would be needed.
Well the biggest problem modularizing your identity definitions is you 
will have more YANG files proportional to the flexibility you want. I 
would have chosen that in the example you provide.
>
> I would be more interested in having an extension saying static-data. 
> This would state that that part of config is set by the system, and 
> can not be modified by the user. So I could have conditions based on 
> it, but the user might not modify it.
That is still not as good as modularization of your model and using 
optionally loadable YANG 'deviation's and 'identity' definitions. Even 
if you have "static-data tree" you will be able to use must statements 
to not allow certain range based on that "static data tree" it will 
still be the range defined in the type from the model that will be shown 
to the user editing the configuration in YANG aware CLI or GUI. It is 
still a workaround even if the must statement will fail upon commit.