Re: [netmod] [Netconf] Alternative YANG library structure for 7895bis

[Vladimir Vassilev <[e-mail]>]

Hello,

I have a proposal based on <get-data> that provides an elegant solution 
to consider as a 3rd option.  It is based on keeping exactly the same 
model as in RFC 7895 and using <get-data> RPC to retrieve datastore 
specific yang-library instance data in a similar way one would use 
<get-data> to retrieve the datastore contents. In addition a top level 
config=false container e.g. /datastores with list of supported 
datastores that does not need to be part of the yang-library module:

module: ietf-datastores
+--ro datastores
|  +--ro datastore* [name]
|     +--ro name          identityref

Vladimir

On 11/09/2017 05:51 PM, Robert Wilton wrote:
>
> Hi,
>
> Given some of the feedback related to the complexity of the YANG 
> library bis structure, we have come up with two other possible 
> structures for the YANG library data:
>
> (1) A simplified structure to make YANG library meet the NMDA 
> requirements, but that is closer to the existing YANG library 
> structure, and arguably simpler.
> (2) An enhanced version of the structure (1) above, that is also 
> extended to allow the structure to be reused for schema-mount via an 
> augmentation.
>
> For reference, at the end of this email, I have also included the tree 
> diagram of the existing YANG library, and the current YANG library bis 
> draft (draft-ietf-netconf-rfc7895bis-02) version.
>
> Considering the two new YANG library structures:
>
> ------------------------
>
> *(1) A simplified structure to make YANG library meet the NMDA 
> requirements, but that is closer to the existing YANG library structure.*
>
> The main changes are:
> (i) Split "implemented modules" and "import-only-modules" into two 
> separate lists, making the most important list (i.e. implemented 
> modules) keyed by module name only and hence easier to reference.
> (ii) Assume modules are implemented in all datastores by default (with 
> a "not-implemented-in" leaflist of datastores that a module is not 
> implemented in).
> (iii) Assume that features are implemented in all datastores by 
> default (with a "not-implemented-in" leaflist of datastores that a 
> feature is not implemented in).
> (iv) Deleted module-sets.
> (v) Datastores are now just a list of supported datastores (that could 
> potentially be extended with further per datastore properties in future).
>
> Manually generated tree output for proposed YANG library:
>
> module: ietf-yang-library
>  +--ro yang-library
>     +--ro modules
>     |  +--ro module* [name]
>     |  |  +--ro name           yang:yang-identifier
>     |  |  +--ro revision?      revision-identifier
>     |  |  +--ro schema?        inet:uri
>     |  |  +--ro namespace      inet:uri
>     |  |  +--ro submodule* [name]
>     |  |  |  +--ro name        yang:yang-identifier
>     |  |  |  +--ro revision?   yang:yang-identifier
>     |  |  |  +--ro schema?     inet:uri
>     |  |  +--ro not-implemented-in*
>     |  |  |              -> /yang-library/datastore/name
>     |  |  +--ro feature* [name]
>     |  |  |  +--ro name        yang:yang-identifier
>     |  |  |  +--ro not-implemented-in*
>     |  |  |              -> /yang-library/datastore/name
>     |  |  +--ro deviation*
>     |  |                 -> ../name
>     |  |
>     |  +--ro import-only-module* [name revision]
>     |     +--ro name yang:yang-identifier
>     |     +--ro revision            union
>     |     +--ro schema?             inet:uri
>     |     +--ro namespace           inet:uri
>     |     +--ro submodule* [name]
>     |        +--ro name        yang:yang-identifier
>     |        +--ro revision    yang:revision-identifier
>     |        +--ro schema?     inet:uri
>     +--ro datastore* [name] // Allows future per datastore properties.
>     |  +--ro name          identityref
>     +--ro checksum       string
>
> ------------------------------
>
> *(2) An enhanced version of the structure (1) above, that is extended 
> to allow the structure to be reused for schema-mount via an augmentation.*
>
> This is similar to the structure above, except that the "the set of 
> modules" is contained in a list of named schema (e.g. similar to the 
> schema mount draft), allowing this structure to be re-used for schema 
> mount.
>
> Schema mount would be expected to augment yang-library to add in the 
> additional schema mount information.  In the tree diagram, I have 
> shown the schema-mount mount-point augmentation, but not including 
> namespaces yet.
>
> Every server would be required to provide at least one schema in the 
> schema list, and the primary schema for the device would always be 
> given the name "primary".
>
> module: ietf-yang-library
>  +--ro yang-library
>     +--ro schema* [name]
>     |  +--ro name           string
>     |  +--ro checksum       string
>     |  +--ro module* [name]
>     |  |  +--ro name           yang:yang-identifier
>     |  |  +--ro revision?      yang:revision-identifier
>     |  |  +--ro schema?        inet:uri
>     |  |  +--ro namespace      inet:uri
>     |  |  +--ro submodule* [name]
>     |  |  |  +--ro name        yang:yang-identifier
>     |  |  |  +--ro revision?   yang:yang-identifier
>     |  |  |  +--ro schema?     inet:uri
>     |  |  +--ro not-implemented-in*
>     |  |  |              -> /yang-library/datastore/name
>     |  |  +--ro feature* [name]
>     |  |  |  +--ro name        yang:yang-identifier
>     |  |  |  +--ro not-implemented-in*
>     |  |  |              -> /yang-library/datastore/name
>     |  |  +--ro deviation*
>     |  |  |              -> ../name
>     |  |  +- schema-mount:mount-point* [label]
>     |  |     +--ro label         yang:yang-identifier
>     |  |     +--ro config?       boolean
>     |  |     +--ro (schema-ref)
>     |  |        +--:(inline)
>     |  |        |  +--ro inline?       empty
>     |  |        +--:(use-schema)
>     |  |           +--ro use-schema* [name]
>     |  |              +--ro name
>     |  |              |       -> /yang-library/schema/name
>     |  |              +--ro parent-reference* yang:xpath1.0
>     |  |
>     |  +--ro import-only-module* [name revision]
>     |     +--ro name yang:yang-identifier
>     |     +--ro revision            union
>     |     +--ro schema?             inet:uri
>     |     +--ro namespace           inet:uri
>     |     +--ro submodule* [name]
>     |        +--ro name        yang:yang-identifier
>     |        +--ro revision    yang:revision-identifier
>     |        +--ro schema?     inet:uri
>     +--ro datastore* [name] // Allows future per datastore properties.
>     |  +--ro name          identityref
>     +--ro checksum       string
>
> Please can you provide comments on these structures, in particular:
>
> Is this version better (i.e. simpler) that the version currently in 
> draft-ietf-netconf-rfc7895bis-02 (below)?
>
> Should we try and make the structure extensible for schema-mount via 
> augmentation (i.e. version (2)), or is it better that schema-mount has 
> its own separate subtree?
>
> For reference only I have included the existing YANG library and YANG 
> library bis draft tree diagrams.
>
> Thanks,
> Rob
>
>
> -----------------------------
>
> *** FOR REFERENCE ONLY ***
>
> (3)  The current YANG library structure in YANG library bis 
> (draft-ietf-netconf-rfc7895bis-02)
>
>     module: ietf-yang-library
>         +--ro yang-library
>            +--ro modules
>            |  +--ro module* [id]
>            |     +--ro id                  string
>            |     +--ro name                yang:yang-identifier
>            |     +--ro revision?           revision-identifier
>            |     +--ro schema?             inet:uri
>            |     +--ro namespace           inet:uri
>            |     +--ro feature*            yang:yang-identifier
>            |     +--ro deviation* [module]
>            |     |  +--ro module    -> ../../id
>            |     +--ro conformance-type    enumeration
>            |     +--ro submodule* [name]
>            |        +--ro name        yang:yang-identifier
>            |        +--ro revision?   revision-identifier
>            |        +--ro schema?     inet:uri
>            +--ro module-sets
>            |  +--ro module-set* [id]
>            |     +--ro id        string
>            |     +--ro module*   -> ../../../modules/module/id
>            +--ro datastores
>            |  +--ro datastore* [name]
>            |     +--ro name          identityref
>            |     +--ro module-set
>            |             -> ../../../module-sets/module-set/id
>            +--ro checksum       string
>
> -----------------------------
>
> *** FOR REFERENCE ONLY ***
>
> (4)  The current YANG library structure (RFC 7895)
>
>        +--ro modules-state
>           +--ro module-set-id    string
>           +--ro module* [name revision]
>              +--ro name                yang:yang-identifier
>              +--ro revision            union
>              +--ro schema?             inet:uri
>              +--ro namespace           inet:uri
>              +--ro feature*            yang:yang-identifier
>              +--ro deviation* [name revision]
>              |  +--ro name        yang:yang-identifier
>              |  +--ro revision    union
>              +--ro conformance-type    enumeration
>              +--ro submodule* [name revision]
>                 +--ro name        yang:yang-identifier
>                 +--ro revision    union
>                 +--ro schema?     inet:uri
>
>
>
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