Re: [netconf] get-data origin filters

[Andy Bierman <[e-mail]>]

On Mon, Oct 7, 2019 at 9:35 AM Rob Wilton (rwilton) <[e-mail]>
wrote:

> My understanding of the intention of the way the filters are logically
> meant to work are:
>
>
>
>    1. Construct the full response to the request (as if no filters are to
>    be returned):
>    2. Restrict the response, so that the selected elements match any
>    subtree filter.
>    3. Restrict the response, so that the selected elements match any
>    xpath filter.
>    4. Restrict the response, so that the selected elements match any
>    config true/false filter.
>    5. Restrict the response, so that the selected elements match any
>    origin filter.
>    6. Constrain to the requested depth
>    7. Add in required ancestors and list keys.
>    8. Return the result.
>
>
The RFC has no such procedure defined.
The text that is there says nothing about matching descendant nodes.

Andy


>
>
>
>
> I don’t see text in the filters that states that if a node is filtered
> then all of its descendants are automatically filtered as well.  I think
> that you are assuming this behaviour.
>
>
>
> A node always only has a single origin, although it could change.  E.g. if
> a system configured was explicitly configured, then it would make sense to
> change its origin to configured because it would exist regardless of
> whether it was originally added by the system.
>
>
>
> Thanks,
>
> Rob
>
>
>
>
>
> *From:* Andy Bierman <[e-mail]>
> *Sent:* 07 October 2019 15:52
> *To:* Rob Wilton (rwilton) <[e-mail]>
> *Cc:* Martin Bjorklund <[e-mail]>; Netconf <[e-mail]>
> *Subject:* Re: [netconf] get-data origin filters
>
>
>
>
>
>
>
> On Mon, Oct 7, 2019 at 7:36 AM Rob Wilton (rwilton) <[e-mail]>
> wrote:
>
> Hi Andy,
>
>
>
> Don’t all the filters effectively work this way?
>
>
>
>
>
> I do not see the text that explains origin-filter and
> negated-origin-filter working the way Martin
>
> describes it.  These filters do not say anywhere to select a node because
> it has descendants
>
> that match the origin filters.  It says very clearly that the filter test
> is on the specified node.
>
> It also says the origin is derived from the origin annotation for that
> node.
>
> Since only 1 instance of the origin annotation is allowed per node, there
> is no way to tag
>
> a node with multiple origins.
>
>
>
> If implementation is too complex then people will just leave it out (w/ a
> deviation).
>
> It is unlikely that the instrumentation knows at any given instant all the
> origin values
>
> of all the descendant dynamic data at the instant the <get-data> request
> is processed.
>
>
>
>
>
>
>
>
>
> They select a subset of the nodes to include in the response, and must
> also include all ancestor nodes and required list keys to the selected
> nodes, regardless of whether those ancestor/key nodes were also selected by
> the query.
>
>
>
>
>
> Yes. Understood.
>
> Still does not explain how a filter for the list node selects descendant
> nodes that match the origin filters.
>
>
>
>
>
> E.g. a “config false” filter will still return “config true” nodes if they
> are ancestors or list keys to a descendant config false node.  The same
> logic applies for xpath and origin filters as well.
>
>
>
>
>
> No they won't.
>
> Where is that text?
>
>
>
>     get-data config=filter=false
>
>
>
> This starts from top-level YANG nodes.
>
> If the top-level YANG node is not config=false then the server will not
> keep looking for descendants that match.
>
>
>
>
>
> Thanks,
> Rob
>
>
>
>
>
> Andy
>
>
>
>
>
>
>
>
>
> *From:* netconf <[e-mail]> *On Behalf Of *Andy Bierman
> *Sent:* 07 October 2019 15:12
> *To:* Martin Bjorklund <[e-mail]>
> *Cc:* Netconf <[e-mail]>
> *Subject:* Re: [netconf] get-data origin filters
>
>
>
>
>
>
>
> On Mon, Oct 7, 2019 at 12:43 AM Martin Bjorklund <[e-mail]> wrote:
>
> Andy Bierman <[e-mail]> wrote:
> > On Sun, Oct 6, 2019 at 8:32 AM Martin Bjorklund <[e-mail]> wrote:
> >
> > > Hi,
> > >
> > > Andy Bierman <[e-mail]> wrote:
> > > > Hi,
> > > >
> > > > I am trying to figure out how to use the origin-filter and
> > > > negated-origin-filter
> > > > in the <get-data> operation in RFC 8526.
> > > >
> > > >
> > > >           leaf-list origin-filter {
> > > >              type or:origin-ref;
> > > >              description
> > > >                "Filter based on the 'origin' annotation.  A
> > > >                 configuration node matches the filter if its 'origin'
> > > >                 annotation is derived from or equal to any of the
> given
> > > >                 filter values.";
> > > >            }
> > > >
> > > >
> > > > These filters seem kind of worthless if implemented according to the
> > > text.
> > > > Consider a simple example where there is 1 learned leaf within a
> list:
> > > >
> > > > module: address
> > > >   +--rw addresses
> > > >      +--rw address* [last-name first-name]
> > > >         +--rw last-name     string
> > > >         +--rw first-name    string
> > > >         +--rw street?       string
> > > >         +--rw city?         string
> > > >         +--rw zipcode?      string
> > > >         +--rw phone* [phone-type]
> > > >            +--rw phone-type      enumeration
> > > >            +--rw phone-number    string
> > > >
> > > > Let's say the "zipcode" field is learned in <operational>
> > > > (e.g. ZIP code lookup expands missing or 5 digit zipcode to full 9
> digit
> > > > zipcode).
> > > > So /addresses and /addresses/address have origin "intended".
> > > > Only the /addresses/address/zipcode leaf has origin "learned".
> > > >
> > > > So how does origin-filter=learned find all the learned leafs?
> > >
> > > Perhaps I don't understand your question; IMO you give the answer to
> > > this question below:
> > >
> > > > What filters are required to return only the learned entries +
> ancestors
> > > +
> > > > ancestor-or-self keys?  Seems like this filter mechanism has to be
> used
> > > > to retrieve the exact leaf that might be learned, and the client
> > > > needs to know in advance all the possible nodes that might be
> learned.
> > > >
> > > > Want to be able to retrieve an ancestor that is intended and still
> find
> > > the
> > > > learned entries
> > > >
> > > >    get-data xpath-filter=/addresses/address origin-filtter=learned
> > >
> > > ... here.  So this request will return:
> > >
> > >    <addresses or:origin="or:intended">
> > >      <address>
> > >        <last-name>...</last-name>
> > >        <first-name>...</first-name>
> > >        <zipcode or:origin="or:learned">...</zipcode>
> > >      </address>
> > >      ...
> > >    </addresses>
> > >
> > >
> > I do not interpret the text the same way as you.
>
> Does this mean that you think that the reply is different from what I
> show above?  If so, what would it be, and why?
>
>
>
>
>
>
>
> Explain how the list address node has origin "learned".
>
>
>
> The filter is for /addresses/address and only origin=learned.
>
> How does the list node have origin=learned?
>
> It can only have 1 value.
>
> It has child nodes with both intended and learned as origin.
>
> I do no understand how the origin=learned matched this node.
>
>
>
>
>
>
>
>
>
> >
> >                      The content returned
> >
> >           by get-data must satisfy all filters, i.e., the filter
> >           criteria are logically ANDed.
> >
> >
> >           leaf-list origin-filter {
> >              type or:origin-ref;
> >              description
> >                "Filter based on the 'origin' annotation.  A
> >                 configuration node matches the filter if its 'origin'
> >                 annotation is derived from or equal to any of the given
> >                 filter values.";
> >            }
> >
> >
> >               Configuration nodes that do not have an
> >               'origin' annotation are treated as if they have the
> >               'origin' annotation 'or:unknown'.
> >
> >
> >
> > > The draft shows an example where both "intended" and "system" are given
> > > > as filters.  This will work but will include all the "intended"
> leafs as
> > > > well.
> > > > What if a "learned" node is within a "system" node within an
> "intended"
> > > > node?
> > >
> > > This works as well.  Note that the get-data description says:
> > >
> > >           Any ancestor nodes (including list keys) of nodes selected by
> > >           the filters are included in the response.
> > >
> > >
> > >
> >
> > The issue is how the /iaddresses and /addresses/address nodes match the
> > origin "learned".
>
> They don't, but they are included b/c of the quoted text above (i.e.:
>       Any ancestor nodes (including list keys) of nodes selected by
>       the filters are included in the response.)
>
>
>
>
>
> No.
>
>
>
> If the filter was for /addresses/address/zipcode then maybe that text
> applies.
>
> It is still unclear that the XPath is fully processed and then the
> origin-filter is processed.
>
> The RFC just says they are ANDed together.
>
>
>
>
>
>
> > The leafs in list "address" are a mixture of "intended" and "learned"
> > origin.
> > The text clearly says that a node has a single origin property, coupled
> to
> > the annotation.
> >
> > Issue 1: mixed origin descendant nodes
> > So how does a search on /addresses/address match origin-filter=learned?
> > I cannot find any text that says what the origin of a list or P-container
> > is if it
> > contains nodes of mixed origin.
>
> See above.
>
>
>
> No text above explains how the list origin is tagged if it has multiple
> types of child nodes.
>
>
>
>
>
>
> > Issue 2: NP-containers
> >
> > Also from RFC 8342:
> >
> >    The origin applies to all configuration nodes except non-presence
> >    containers.
> >
> >
> > What if the top-level node is an NP-container in this case.
> > I thought the top-level node MUST have an origin attribute.
> >
> > The text is not clear how NP-containers are handled.
> > Do they have an origin attribute? If not then RFC 8526 says they have
> > origin "unknown".
> > Is the intent that NP-containers always pass the origin-filter tests
> (test
> > skipped)?
>
> No, since they don't have an origin value they will not be selected by
> the filter.  But an NP-container will be included in the reply if it
> is the ancestor of a node that is selected by the filter.
>
>
>
> The RFC text does not really say that.
>
> Since it is very difficult to know if a data node 5 layers deep is going
> to match,
>
> implementing these filters according to this vague interpretation is
> unlikely.
>
>
>
>
> /martin
>
>
>
> Andy
>
>
>
>
>
> >
> >
> >
> > /martin
> > >
> > >
> > Andy
> >
> >
> > >
> > > > Seems like the client needs to know a lot about the server
> implementation
> > > > details
> > > > in order to use the origin filters.
> > > >
> > > >
> > > > Andy
> > >
>
>