Re: [netmod] Action and RPC statements

Juergen Schoenwaelder <j.schoenwaelder@jacobs-university.de> Tue, 31 October 2017 16:51 UTC

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Date: Tue, 31 Oct 2017 17:49:56 +0100
From: Juergen Schoenwaelder <j.schoenwaelder@jacobs-university.de>
To: Kent Watsen <kwatsen@juniper.net>
Cc: Robert Wilton <rwilton@cisco.com>, Martin Bjorklund <mbj@tail-f.com>, "andy@yumaworks.com" <andy@yumaworks.com>, "netmod@ietf.org" <netmod@ietf.org>, Randy Presuhn <randy_presuhn@alumni.stanford.edu>
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Subject: Re: [netmod] Action and RPC statements
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On Tue, Oct 31, 2017 at 03:35:38PM +0000, Kent Watsen wrote:
> 
> Hi Robert,
> 
> > 6.2 Invocation of RPC Operations 
> >
> > This section updates section 7.14 of RFC 7950. 
> > 
> > RPCs MAY be defined as affecting the contents of a specific datastore, 
> > any configuration datastore (e.g., <edit-config>), or any datastore 
> > (e.g., <get-data>).  The RPC definition specifies how the RPC input 
> > data is interpreted by the server. 
> 
> s/MAY/may/? - is this draft providing for this, or should it come from
> e.g., RFC 7950?
> 
> 
> > RPCs definitions that do not explicitly state an affected 
> > datastore(s) modify the general operational state of the server. 
> > Hence, if any RPC input data relates to data node instances then 
> > those would generally resolve to data node instances in the 
> > <operational> data tree. 
> 
> I reordered first sentence, and added a comma to the second:
> 
> RPCs modify the general operational state of the server, unless
> explicitly defined to affect other datastores. Hence, if any RPC
> input data relates to data node instances, then those would
> generally resolve to data node instances in the <operational>
> data tree. 

- s/the general operational state/the operational state/
- I also do not think that RPC generally modify state.

Or simply:

  References to data nodes in RPC description statements etc. are
  interpreted as references to data nodes in <operational> unless
  specified otherwise.
 
> > 6.3 Invocation of Actions 
> > 
> > This section updates section 7.15 of RFC 7950. 
> >
> > In YANG data models, the "action" statement may appear under "config 
> > true" and "config false" schema nodes.  While instances of both 
> > schema nodes may appear in <operational>, instances of "config true" 
> > schema nodes may also appear in other datastores. 
> 
> okay
> 
> > Actions are always invoked on a data node instance that exist in the 
> > <operational> data tree.  The behavior defined by an action statement 
> > is generally expected to affect the operational state of the server 
> > rather than directly modifying the contents of any configuration 
> > datastore. 
> 
> fixed plurality issue in first sentence, and removed wishy-washy 
> language from the rest:
> 
> Actions are always invoked on a data node instance that exists in the 
> <operational> data tree.  Action statements affect the operational
> state of the server.

OR:

  References to data nodes in action description statements etc. are
  interpreted as references to data nodes in <operational> unless
  specified otherwise.

I think that the data node an action is bound to must exist in
operational state - this is consistent with the xpath context. But
what the other parameters mean is a matter of the action/RPC
semantics, as defined in the description statement. Or is there a
_technical_ reason to restrict this?

/js

-- 
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/>