Re: [netmod] YANG action not allowed at root?

Hi,

If we were to redo YANG, I would prefer to have a single statement
"operation", either on the top-level, or tied to a node.

/martin

Christian Hopps <chopps@chopps.org> wrote:
> An action is defined as being something bound to a node. Talking about
> actions that aren't bound to a node is talking about RPCs AFAICT. In
> the server it just comes down to passing the bound node data in to the
> function or not. Defining "unbound actions" to replace RPCs is just
> different syntax for the same thing, right? Having 2 ways to do the
> same thing wouldn't help make servers easier to implement (it would do
> the opposite actually).
> 
> Thanks,
> Chris.
> 
> > On Apr 30, 2020, at 11:50 AM, Sterne, Jason (Nokia - CA/Ottawa)
> > <jason.sterne@nokia.com> wrote:
> > 
> > Yes - the intent was to address the limitation that an RPC can only be
> > at root. Actions can be out in a tree & nicely associated with
> > something (e.g. instead of having a pile of flat RPCs with long names
> > that encode containers like reset-www-xxx-yyy-zzz-entity).
> >  
> > But I don't really understand why we limited actions from being at the
> > root. It prevents a strategy of implementing all operations in a
> > server (some of which may be desirable at root for various reasons,
> > some of which may be desirable in the tree) as actions.
> >  
> > Why not allow this?
> >  
> >    module bar {
> >          action do-stuff {
> >            input {
> >              leaf iterations {
> >                type uint8;
> >               }
> >             }
> >          } 
> >        } 
> >    } 
> >  
> > Which could be called from NETCONF like this:
> >  
> >      <rpc message-id="101"
> >           xmlns="urn:ietf:params:xml:ns:netconf:base:1..0">
> >        <action xmlns="urn:ietf:params:xml:ns:yang:1">
> >          <do-stuff xmlns="urn:example:bar">
> >            <iterations>5</iterations>
> >          </do-stuff>
> >        </action>
> >      </rpc>
> >  
> >  
> > Jason
> >  
> > From: Reshad Rahman (rrahman) <rrahman@cisco.com> 
> > Sent: Thursday, April 30, 2020 11:31 AM
> > To: Sterne, Jason (Nokia - CA/Ottawa) <jason.sterne@nokia.com>;
> > netmod@ietf.org
> > Subject: Re: [netmod] YANG action not allowed at root?
> >  
> > I don’t know the history on this but the intent is to have action tied
> > to a data node.
> >  
> > https://tools.ietf.org/html/rfc7950#section-7.15
> >    The difference between an action and an rpc is that an action is tied
> >    to a node in the datastore, whereas an rpc is not.  When an action is
> >    invoked, the node in the datastore is specified along with the name
> >    of the action and the input parameters.
> >  
> > Regards,
> > Reshad.
> >  
> > From: netmod <netmod-bounces@ietf.org> on behalf of "Sterne, Jason
> > (Nokia - CA/Ottawa)" <jason.sterne@nokia.com>
> > Date: Thursday, April 30, 2020 at 11:08 AM
> > To: "netmod@ietf.org" <netmod@ietf.org>
> > Subject: [netmod] YANG action not allowed at root?
> >  
> > Hi all,
> >  
> > I was a bit surprised to find this in section 7.15 of 7950 recently:
> >  
> >    Since an action cannot be defined at the top level of a module or in
> >    a "case" statement, it is an error if a grouping that contains an
> >    action at the top of its node hierarchy is used at the top level of a
> >    module or in a case definition.
> >  
> > I realize that actions can be placed down in a schema tree (i.e. sit
> > in the context of a container or list), but why is it phrased that
> > they *must* be in a container?
> >  
> > RPCs are limited to being at the root. I would have thought actions
> > could be anywhere (root or down in the tree).
> >  
> > Jason
> >  
> >  
> > _______________________________________________
> > netmod mailing list
> > netmod@ietf.org
> > https://www.ietf.org/mailman/listinfo/netmod
> 
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