Hi Rob, A few comments, inline
--- Alex From: netmod [mailto:netmod-boun...@ietf.org] On Behalf Of Robert Wilton Sent: Tuesday, October 31, 2017 7:14 AM To: Martin Bjorklund <m...@tail-f.com>; a...@yumaworks.com; netmod@ietf.org; Randy Presuhn <randy_pres...@alumni.stanford.edu> Subject: Re: [netmod] Action and RPC statements Hi, Here is another attempt for proposed text for Actions/RPC statements in NMDA. <new> 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. <ALEX> why “e.g., <get-data>”? Does <get-data> affect the contents of the datastore – I thought it just gets data, hence this example is not ideal. There is also no mention about the source of the “in” parameters. It probably makes sense to mention that explicitly. Perhaps something along the lines of “RPCs MAY be defined as _relating_ to the contents of a specific datastore…. Input data resolves to <operational>, as does output data, as do RPC side effects“. Then below “RPCs definitions that do not explicitly state an affected datastore(s) _refer_to_ the general operational state of the server.” One other comment, it would be good to also indicate that when an RPC leads to modification of data nodes, what the “origin” of those modifications is. </ALEX> 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. 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. 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. </new> On a related note, I also want to confirm that it is right that RPC input data is always checked against operational: Section 6.1. of the NMDA draft states: o If the XPath expression is defined in a substatement to an "input" statement in an "rpc" or "action" statement, the accessible tree is the RPC or action operation instance and all operational state in the server. The root node has top-level data nodes in all modules as children. Additionally, for an RPC, the root node also has the node representing the RPC operation being defined as a child. The node representing the operation being defined has the operation's input parameters as children. Is <operational> always the right datastore to evaluate RPC input/output data relative to? For most RPCs this seems to be the right choice by default but it also seems plausible that someone may wish to define an RPC that wants to validate its input parameters against the contents of another datastore. An example could be an "is-applied" RPC that takes a path to a subtree in <running> or <intended> and checks whether the configuration for that subtree is fully represented in <operational>. Thanks, Rob On 27/10/2017 09:33, Martin Bjorklund wrote: Andy Bierman <a...@yumaworks.com><mailto:a...@yumaworks.com> wrote: On Thu, Oct 26, 2017 at 11:22 AM, Randy Presuhn < randy_pres...@alumni.stanford.edu<mailto:randy_pres...@alumni.stanford.edu>> wrote: Hi - On 10/26/2017 10:44 AM, Robert Wilton wrote: Hi , Separating out the issue regarding which datastore action and RPC apply to, we propose the following NEW text to the datastores draft: 6.2 Invocation of Actions and RPC Operations 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. An NMDA compliant server MUST execute all actions in the context of <operational>. Likewise, an NMDA compliant server MUST invoke all RPC operations in the context of <operational>, unless the RPC is explicitly defined as affecting other datastores (e.g., <edit-config>). OK? A question - I understand the motivation for the "unless" for RPC operations, but wonder why there is no similar "unless" for actions. The <rpc> is not really in a datastore at all. It may have input and output parameters with leafref and must/when statements. These are evaluated in the <operational> context. The <rpc> may in fact be something like <edit-config> which has parameters (like <config> to apply to a specific datastore. The action node is embedded within some data that has to be parsed in a specific datastore before the action is processed. This data is required to be in <operational>. It also has XPath and leafref that needs to be resolved (same as <rpc>). The side effects of the <rpc> or <action> can impact other datastores. This would be defined in the description-stmt and this is not a problem. This is exactly right. We need to capture this in the text. /martin _______________________________________________ netmod mailing list netmod@ietf.org<mailto:netmod@ietf.org> https://www.ietf.org/mailman/listinfo/netmod .
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