Re: [netconf] edit-config leaf without value

["Rob Wilton (rwilton)" <[e-mail]>]

[As a contributor]

Hi Michal,

Please see inline ...

> -----Original Message-----
> From: netconf <[e-mail]> On Behalf Of Michal Vaško
> Sent: 06 March 2020 15:10
> To: netconf <[e-mail]>
> Subject: [netconf] edit-config leaf without value
> 
> Hello,
> we would like some input on a problem that was discussed several times
> based on our search of the mailing list archive but we are still not sure
> what the exact rules are.
> 
> So, let's say we have YANG snippet
> 
> leaf l {
>     type uint32;
> }
> 
> and edit-config config (assume correct namespaces)
> 
> <l operation="delete"/>
> 
> a) Is the example allowed? Meaning can the leaf "l" be without a value
> (have an invalid value)? Based on the YANG 1.1 RFC [1] I would say it
> cannot.
[RW] 
Yes, a value does not need to be provided, but the leaf must previously exist in the configuration, or an error is returned.

I think that this would be the normal way this operation is expressed.


> b) If it can be without a value, is it only in the case of "delete"
> operation, otherwise it is an error?
[RW] 
"remove" would be similar but would not error if the node doesn't exist.

> c) If the leaf "l" had a string type, for example, and there was an
> instance with value "string" in the datastore, would the edit-config
> succeed and the leaf be deleted? In other words, when deleting a leaf, do
> the values have to match for a successful delete or not? In this case, I
> would say the values do not have to match [2].
[RW] 
For a delete operation, if a value was provided, then I would check it or return an error if it did not match.

For a remove operation, I wouldn't perform the check, and just remove the node if it exists.

> d) I am assuming none of this can work for a leaf-list [3] or list [4],
> which must always have the exact value/keys no matter what the operation
> on them is.
[RW] 
Agreed.

Thanks,
Rob


> 
> Thank you for any clarification.
> 
> Regards,
> Michal
> 
> [1] https://tools.ietf.org/html/rfc7950#section-7.6.6
> [2] https://tools.ietf.org/html/rfc7950#section-7.6.7
> [3] https://tools.ietf.org/html/rfc7950#section-7.7.9
> [4] https://tools.ietf.org/html/rfc7950#section-7.8.6
> 
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