Subject: [netmod] validity of instance-data

From: Ladislav Lhotka <[email-masked]>
Date: Tue, 06 Nov 2018 16:59:28 +0700

Hi,

the second bullet of Appendix A in
draft-ietf-netmod-yang-instance-file-format-00 talks about
validity. This would make sense if we have a complete schema - YANG
modules, even with revisions, is not enough. The schema can be provided
off-line but it can also be specified as a part of the metadata.

I would suggest to extend the metadata with the following two optional
methods of specifying the schema:

1. the schema can be specified in-line, for example in the format of the
   new YANG library, i.e. as a list of module-sets

2. A URL specifying the location of the schema.

Lada

-- 
Ladislav Lhotka
Head, CZ.NIC Labs
PGP Key ID: 0xB8F92B08A9F76C67

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From: Balázs Lengyel <[email-masked]>
Date: Fri, 23 Nov 2018 14:33:36 +0000

Hello Lada,

I like your idea idea, thanks. Adding some more details :

     Metadata MUST include:

    o  Name of the instance data set

    o  target: Specifies the method and details by which the target YANG
       modules, supported features and deviations are specified.  The
       specified target only indicates the set of modules that were used
       to define this YANG instance data set.  Whether the instance data
       set is usable for a different real-life target YANG module set
       depends on the compatibility between the specified target and the
       real-life target YANG module set (considering revisios, features,
       devaiations)

    Metadata SHOULD include:

    o  Revision date of the instance data set

    o  Description of the instance data set.  The description SHOULD
       contain information whether and how the data can change during the
       lifetime of the YANG server.

    Target SHALL use one of the following methods:

    IN-LINE Method.  Target should bet set to:

       'inline:ietf-yang-library@' revision-date '.yang'

       E.g. inline:[email-masked]

    The revision date is mandatory, it specifies the revision of the
    ietf-yang-library used by the in-line method.  When using the in-line
    method the first group of data inside the "anydata data" element MUST
    be the instance data targeted at the ietf-yang-library.  This data
    SHALL specify the target YANG modules, revisions, supported features
    and deviations for this and all the other target YANG modules.

    URI Method.  Target MUST bet set to a URI that references another
    YANG instance data file.  The first instance data file will use the
    same set of target YANG modules, revisions, supported features and
    deviations as this other referenced YANG instance data file.  The
    referenced YANG instance data file might use the in-line method or
    might use the URI method to reference further instance data file(s).
    However at the end of this reference chain there MUST be an instance
    data file using the in-line method.  This last instance data file
    MUST carry instance data for the ietf-yang-library, but often will
    carry no other instance data.  If a referenced instance data file is
    not available the revision data, supported features and devaitions
    for the target YANG modules are unknown.

    TODO: extend example with target.

regards Balazs

-- 
Balazs Lengyel                       Ericsson Hungary Ltd.
Senior Specialist
Mobile: +36-70-330-7909              email: [email-masked]