Andy Bierman <[email protected]> wrote:
> On Thu, Jun 15, 2017 at 8:41 AM, Martin Bjorklund <[email protected]> wrote:
>
> > Andy Bierman <[email protected]> wrote:
> > > On Thu, Jun 15, 2017 at 5:27 AM, Juergen Schoenwaelder <
> > > [email protected]> wrote:
> > >
> > > > Andy,
> > > >
> > > > section 5.1 of draft-ietf-netmod-revised-datastores-02.txt discusses
> > > > the XPath context. An xpath expression in a config-false container
> > > > will resolve to the operational state.
> > > >
> > > >
> > >
> > > So the usual method of "augment when" is broken:
> > >
> > > WRONG: Will evaluate when-stmt against config
> > >
> > > augment /foo {
> > > when "some condition";
> > > container stats { }
> > > }
> >
> > Do you mean that stats is a config true container? And presumably in
> > the stats containter you have config false leafs?
> >
> >
> no -- stats is a config false container
Ok. Well, then this is also ok. The stats container will exist if
"some condition" is true in the operational state datastore.
> > I think this works as expected. In a conventional datastore
> > (e.g. running), the stats container exists if "some condition" is true
> > in that datastore.
> >
>
>
> no -- in my example the desire is to augment the operational state based on
> the
> operational value of a config=true leaf
Yes, that will happen in both cases.
> > In the operational state, the stats container exists if "some
> > condition" is true in that the operational state datastore.
> >
> > > Correct: Will evaluate when-stmt against operational:
> > >
> > > augment /foo {
> > > container stats {
> > > config false;
> > > when "different condition";
> > > }
> > > }
> >
> > In this case the stats container will never exist in any conventional
> > datastore, since it is config false.
> >
> > In the operational state, the stats container exists if "different
> > condition" is true in that the operational state datastore.
> >
> > > Forcing the augmenting node to be the XPath context node impacts the
> > > possible expressions.
> > > I think the RD draft should make all this clear.
> >
> > This is not different from how it works today wrt candidate vs running
> > for example.
> >
>
> no -- the datastore doesn't change based on the context node config-stmt
> value
> for candidate and running.
The datastore doesn't change with NMDA either - an XPath expression is
always evaluated in a particular datastore, just like before. There
is no mechanism to read data from a different datastore in the XPath
expressions.
/martin
>
>
>
> >
> >
> > /martin
> >
> >
> >
>
> Andy
>
>
> >
> > >
> > >
> > >
> > > /js
> > > >
> > >
> > >
> > > Andy
> > >
> > >
> > > >
> > > > On Wed, Jun 14, 2017 at 11:07:35AM -0700, Andy Bierman wrote:
> > > > > Hi,
> > > > >
> > > > > I don't know if getting rid of /foo-state is such a great idea,
> > > > > especially wrt/ counters and other objects that are not
> > > > > related to intended config vs. applied config.
> > > > >
> > > > > Q1) how does a client know the difference between an auto-generated
> > > > > foo-state.yang and a real foo-state.yang? Seem like a YANG extension
> > > > > is needed to flag an auto-generated foo-state.yang
> > > > >
> > > > > Q2) How does XPath reference an operational node if the /foo-state
> > > > > subtree has been moved to the /foo config subtree?
> > > > >
> > > > > module foo {
> > > > >
> > > > > container foo {
> > > > > leaf stat-collect-type {
> > > > > type enumeration {
> > > > > enum stat-set1;
> > > > > enum stat-set2;
> > > > > }
> > > > > }
> > > > > }
> > > > >
> > > > > container foo-state {
> > > > > config false;
> > > > > leaf stat-collect-type {
> > > > > type enumeration {
> > > > > enum stat-set1;
> > > > > enum stat-set2;
> > > > > }
> > > > > }
> > > > > container stat-set1 {
> > > > > when "../stat-collect-type = 'stat-set1'";
> > > > > ...
> > > > > }
> > > > > container stat-set2 {
> > > > > when "../stat-collect-type = 'stat-set2'";
> > > > > ...
> > > > > }
> > > > > }
> > > > > }
> > > > >
> > > > > In this example, there is a request stat collect type
> > > > /foo/stat-collect-type
> > > > > and there is an operational value (what the server/device is capable
> > > > > of collecting -- e.g. client requests stat-set2 knowing the server
> > > > > will change it to stat-set1 if set2 not supported)
> > > > >
> > > > > So if /foo-state is folded into /foo (because that is the intent --
> > to
> > > > get
> > > > > rid of this extra stat-collect-type leaf), then how do the when-stmts
> > > > > get applied to the operational value instead of the configured value?
> > > > > The same issue applies if the when-stmts are within an augment-stmt
> > > > >
> > > > > WANT:
> > > > >
> > > > > augment /foo-state {
> > > > > when "stat-collect-type = 'stat-set1'";
> > > > > container stat-set1 {
> > > > > ...
> > > > > }
> > > > > }
> > > > >
> > > > > RD Provides:
> > > > >
> > > > > augment /foo {
> > > > > when "stat-collect-type = 'stat-set1'";
> > > > > container stat-set1 {
> > > > > config false;
> > > > > ...
> > > > > }
> > > > > }
> > > > >
> > > > > There is no way to use when-stmt to reference the operational value.
> > > > > This is a rather common usage of the when-stmt, so it should not
> > > > > be removed if RD is used.
> > > > >
> > > > >
> > > > >
> > > > > Andy
> > > >
> > > > > _______________________________________________
> > > > > netmod mailing list
> > > > > [email protected]
> > > > > https://www.ietf.org/mailman/listinfo/netmod
> > > >
> > > >
> > > > --
> > > > Juergen Schoenwaelder Jacobs University Bremen gGmbH
> > > > Phone: +49 421 200 3587 Campus Ring 1 | 28759 Bremen | Germany
> > > > Fax: +49 421 200 3103 <http://www.jacobs-university.de/>
> > > >
> >
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