Re: [netmod] Action and RPC statements

[Lou Berger <[e-mail]>]

Martin,

If I have an RPC or action that changes state, how would the persistence of 
that state be indicated with an NMBA data stores.  I expected it to be 
related to the data store, but I read your mail below as saying otherwise
Thanks,
Lou


On November 6, 2017 8:20:12 AM Martin Bjorklund <[e-mail]> wrote:

> Hi,
>
> Trying to summarize this issue.
>
> The problem is which datastore is used to:
>
>     1a. evaluate action ancestor nodes
>     1b. evaluate action input/output parameter leafref,
>         instance-identifier, must, when
>     2.  evaluate rpc input/output parameter leafref,
>         instance-identifier, must, when
>
> (Note that the side effects of an action/rpc is not part of this
> issue)
>
> I think it would be very weird if 1a and 1b were treated differently,
> so I just label them as 1 below.
>
> Possible solutions:
>
> A.  Always use <operational> for 1 and 2.
>
>     (This is what the current nmda draft says).
>
> B.  Let the client specify the datastore for 1, and use <operational>
>     for 2.
>
>     (Note that this is trivial in RESTCONF (since the datastore is
>     part of the URL), but would require a new parameter for NETCONF
>     (or a new <action2>).
>
> C.  Let the client specify the datastore for 1 and 2.
>
>     This would require a new generic parameter for how RPCs are
>     invoked in both NETCONF and RESTCONF.
>
> D.  Like B, but let the description of the "rpc" statement optionally
>     override this.
>
>
> I prefer B and then D.
>
>
> /martin
>
>
>
>
> Andy Bierman <[e-mail]> wrote:
>> On Thu, Nov 2, 2017 at 2:16 PM, Phil Shafer <[e-mail]> wrote:
>>
>> > Sorry, if I wasn't clear.  I meant the <datastore> element would
>> > be directly under <action>, so the system knows where to start
>> > looking for data.  Guessing is bad.
>> >
>> >
>> Totally agree guessing is bad.
>> Did you see the <action2> proposal in a previous email?
>> That is exactly what I proposed, except I do not want to
>> overload <action> so the new template would be a different name.
>>
>> I realize the expanded name of the datastore element prevents it from
>> being confused with top-level YANG nodes, but the conformance
>> is more clear with a new name.
>>
>>
>>
>>
>> > Thanks,
>> >  Phil
>> >
>>
>> Andy
>>
>>
>> >
>> >
>> > Andy Bierman writes:
>> > >So a server will be required to guess the correct datastore until it
>> > >finds the right one that matches the action instance?
>> > >
>> > >   <action>
>> > >       <top>
>> > >          <list1>
>> > >             <key>10</key>
>> > >             <do-test>
>> > >                <datastore>candidate</datastore>
>> > >             </do-test>
>> > >          </list1>
>> > >        </top>
>> > >    </action>
>> > >
>> > >The server will guess the datastore in some proprietary order and parse
>> > >instances of /top/ and /top/list1.  Then it finds the <do-test> action
>> > >and parses the input to get to the datastore and find out the real
>> > datastore
>> > >to use.  If the server guessed wrong, then it reparses the <action>
>> > against
>> > >the requested datastore.  Hopefully the schema trees match up.
>> > >
>> > >Will vendors do all the extra work required to support this sort of thing?
>> > >I doubt it.
>> > >
>> > >
>> > >Andy
>> > >
>> > >
>> > >
>> > >
>> > >On Tue, Oct 31, 2017 at 11:36 PM, Phil Shafer <[e-mail]> wrote:
>> > >
>> > >> Robert Wilton writes:
>> > >> >ii) However, as far as I can see, it doesn't make sense for an action
>> > to
>> > >> >directly affect the contents of any configuration datastore, that
>> > should
>> > >> >be done via a purpose built rpc (like edit-config).
>> > >>
>> > >> An example action would be to retrieve the  fingerprint of an ssh
>> > >> key.  I might want to get the fingerprint of a key in <candidate>
>> > >> before I commit it.
>> > >>
>> > >> Or I could have an action that sets the SNMPv3 auth key to a random
>> > >> value, and I want to invoke that action against <candidate>.
>> > >>
>> > >> Seems like <startup> might also be an interesting place to target
>> > >> actions, but I can't think of a good example.
>> > >>
>> > >> There are always scenarios where something is useful, and the problem
>> > >> with ruling it out is that it becomes needed at some later point.
>> > >> We've a habit of ruling out things and later wishing we had them.
>> > >>
>> > >> Is the easy fix to just put a datastore leaf under rpc/action and
>> > >> have it default to operational?  Any specific RPC can define its
>> > >> own datastore leaf of hard-code the database in the description
>> > >> (explicitly or implicitly <operational>), but the <action> RPC only
>> > >> gets this if we make a new parameter for it.
>> > >>
>> > >> Thanks,
>> > >>  Phil
>> > >>
>> > >
>> > >--001a11411b0ad2d58d055cee96cb
>> > >Content-Type: text/html; charset="UTF-8"
>> > >Content-Transfer-Encoding: quoted-printable
>> > >
>> > ><div dir=3D"ltr">Hi,<div><br></div><div>So a server will be required to
>> > gue=
>> > >ss the correct datastore until it</div><div>finds the right one that
>> > matche=
>> > >s the action instance?</div><div><br></div><div>=C2=A0
>> > =C2=A0&lt;action&gt;=
>> > ></div><div>=C2=A0 =C2=A0 =C2=A0 =C2=A0&lt;top&gt;</div><div>=C2=A0
>> > =C2=A0 =
>> > >=C2=A0 =C2=A0 =C2=A0 &lt;list1&gt;</div><div>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =
>> > >=C2=A0 =C2=A0 =C2=A0&lt;key&gt;10&lt;/key&gt;</div><div>=C2=A0 =C2=A0
>> > =C2=
>> > >=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0&lt;do-test&gt;</div><div>=C2=A0 =C2=A0
>> > =C2=
>> > >=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 &lt;datastore&gt;candidate&lt;
>> > /datas=
>> > >tore&gt;</div><div>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0
>> > =C2=A0&lt;/do-=
>> > >test&gt;</div><div>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0
>> > &lt;/list1&gt;</div><=
>> > >div>=C2=A0 =C2=A0 =C2=A0 =C2=A0 &lt;/top&gt;</div><div>=C2=A0 =C2=A0
>> > &lt;/a=
>> > >ction&gt;</div><div><br></div><div>The server will guess the datastore
>> > in s=
>> > >ome proprietary order and parse</div><div>instances of /top/ and
>> > /top/list1=
>> > >.=C2=A0 Then it finds the &lt;do-test&gt; action</div><div>and parses the
>> > i=
>> > >nput to get to the datastore and find out the real datastore</div><div>to
>> > u=
>> > >se.=C2=A0 If the server guessed wrong, then it reparses the
>> > &lt;action&gt; =
>> > >against</div><div>the requested datastore.=C2=A0 Hopefully the schema
>> > trees=
>> > > match up.</div><div><br></div><div>Will vendors do all the extra work
>> > requ=
>> > >ired to support this sort of thing?</div><div>I doubt
>> > it.</div><div><br></d=
>> > >iv><div><br></div><div>Andy</div><div><br></div><div><br></
>> > div><div><br></d=
>> > >iv><div><div class=3D"gmail_extra"><br><div class=3D"gmail_quote">On Tue,
>> > O=
>> > >ct 31, 2017 at 11:36 PM, Phil Shafer <span dir=3D"ltr">&lt;<a
>> > href=3D"mailt=
>> > >o:[e-mail]" target=3D"_blank">[e-mail]</a>&gt;</span>
>> > wrote=
>> > >:<br><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0
>> > .8ex;border-le=
>> > >ft:1px #ccc solid;padding-left:1ex">Robert Wilton writes:<br>
>> > >&gt;ii) However, as far as I can see, it doesn&#39;t make sense for an
>> > acti=
>> > >on to<br>
>> > >&gt;directly affect the contents of any configuration datastore, that
>> > shoul=
>> > >d<br>
>> > >&gt;be done via a purpose built rpc (like edit-config).<br>
>> > ><br>
>> > >An example action would be to retrieve the=C2=A0 fingerprint of an ssh<br>
>> > >key.=C2=A0 I might want to get the fingerprint of a key in
>> > &lt;candidate&gt=
>> > >;<br>
>> > >before I commit it.<br>
>> > ><br>
>> > >Or I could have an action that sets the SNMPv3 auth key to a random<br>
>> > >value, and I want to invoke that action against &lt;candidate&gt;.<br>
>> > ><br>
>> > >Seems like &lt;startup&gt; might also be an interesting place to
>> > target<br>
>> > >actions, but I can&#39;t think of a good example.<br>
>> > ><br>
>> > >There are always scenarios where something is useful, and the problem<br>
>> > >with ruling it out is that it becomes needed at some later point.<br>
>> > >We&#39;ve a habit of ruling out things and later wishing we had them.<br>
>> > ><br>
>> > >Is the easy fix to just put a datastore leaf under rpc/action and<br>
>> > >have it default to operational?=C2=A0 Any specific RPC can define its<br>
>> > >own datastore leaf of hard-code the database in the description<br>
>> > >(explicitly or implicitly &lt;operational&gt;), but the &lt;action&gt;
>> > RPC =
>> > >only<br>
>> > >gets this if we make a new parameter for it.<br>
>> > ><br>
>> > >Thanks,<br>
>> > >=C2=A0Phil<br>
>> > ></blockquote></div><br></div></div></div>
>> > >
>> > >--001a11411b0ad2d58d055cee96cb--
>> >
>
> _______________________________________________
> netmod mailing list
> [e-mail]
> https://www.ietf.org/mailman/listinfo/netmod
>