[Netconf] Yangdoctors last call review of draft-ietf-netconf-netconf-event-notifications-16

[Reshad Rahman <[e-mail]>]

Reviewer: Reshad Rahman
Review result: Ready with Issues

YANG Doctor review of draft-ietf-netconf-netconf-event-notifications-16 (by
Reshad Rahman)

No YANG module in this draft but there are numerous examples based on the YANG
modules in draft-ietf-netconf-subscribed-notifications and
draft-ietf-netconf-yang-push. Validation of the examples was done with yanglint
0.16.59.

The major issues are related to the examples, although in 2) below  the
root-cause might be with the YANG module in
draft-ietf-netconf-subscribed-notifications  and in 3) there is an issue which
has already been reported on draft-ietf-netconf-yang-push: 1) The
establish-subscription request in Figure 3 fails yanglint validation, the
"stream" element has to be moved after the "stream-xpath-filter" element, that
fixed the following issue: err : Invalid order of elements
"stream-xpath-filter" and "stream".
(/ietf-subscribed-notifications:establish-subscription/stream-xpath-filter) 2)
The establish-subscription error response in Figure 5 fails yanglint
validation, the "id" element is missing. This is because
draft-ietf-netconf-subscribed-notifications has leaf id as mandatory in
establish-subscription output, either we remove the mandatory or we reserve a
value as invalid id or we add err : Missing required element "id" in
"establish-subscription".
(/ietf-subscribed-notifications:establish-subscription) 3) The
modify-subscription request in Figure 7 fails yanglint validation because of
missing "datastore" element. err : When condition
"../ietf-subscribed-notifications:target/ietf-yang-push:datastore" not
satisfied.
(/ietf-subscribed-notifications:modify-subscription/ietf-yang-push:periodic)
There are 2 causes here: missing "datastore" element and incorrect when
statements in draft-ietf-netconf-yang-push (as reported by Andy Bierman).
Fixing ietf-yang-push.yang and adding the following before element
"datastore-xpath-filter " fixed the example.
    <yp:datastore
    xmlns:ds="urn:ietf:params:xml:ns:yang:ietf-datastores">ds:running</yp:datastore>

Minor comments and nits:
- Abstract s/YANG Push/YANG-Push/ since YANG-Push is the term introduced in
draft-ietf-netconf-yang-push - Introduction. Last sentence doesn't read well,
"...a RESTCONF client via a dynamic subscription..." may need tweaking -
Section 5 s/terminates/terminates,/ - Section 7 3rd bullet. s/this MAY but does
not have to be included/this MAY be included/? - Section 7
s/kill-subscription-error/delete-subscription-error/ (thanks Rob) - Figure 3,
stream-xpath-filter uses prefix "ds" for example-datastore.yang. Since "ds" is
used by ietf-datastores.yang, might be better to choose another prefix such as
"ex"

Regards,
Reshad.