YANG module file name convention
draft-ietf-netmod-yang-module-filename-01

NETMOD Working Group                                        P. Andersson
Internet-Draft                                             Cisco Systems
Updates: 6020, 7950, 8407 (if approved)                 25 February 2025
Intended status: Standards Track                                        
Expires: 29 August 2025

                    YANG module file name convention
               draft-ietf-netmod-yang-module-filename-01

Abstract

   This document presents YANG module file name convention.  The
   convention extends the current YANG module file name using
   revision-date, with the YANG semantic version extension.  The YANG
   semantic version extension allows for an informative version to be
   associated with a particular YANG module revision.

Editorial note (To be removed by the RFC Editor)

   In the YANG module versioning work it was previously defined in
   [I-D.ietf-netmod-yang-semver] that file names could use the revision
   label (YANG Semantic version extension) instead of the revision date,
   which is standardized in [RFC7950].  This work was removed in an
   attempt to progress the module versioning work, but the YANG
   versioning design team was tasked to address it by the NETMOD WG.
   This draft extends YANG module file names conformity with the
   possibility to use revision label in addition to revision date.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 29 August 2025.

Andersson                Expires 29 August 2025                 [Page 1]
Internet-Draft      YANG module file name convention       February 2025

Copyright Notice

   Copyright (c) 2025 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components
   extracted from this document must include Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Motivation  . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Module file names . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Coexistence with YANG Semver  . . . . . . . . . . . . . .   3
     2.2.  Known incompatibilities . . . . . . . . . . . . . . . . .   4
   3.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   4.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     4.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
     4.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .   5
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   This document defines the YANG module file convention.  It extends
   the current convention defined in [RFC7950], which uses revision-
   date, with the YANG semantic version extension defined in
   [I-D.ietf-netmod-yang-semver].

1.1.  Motivation

   The motivation for using YANG semantic version instead of revision
   date is that it carries information to the user.  A revision date
   only tells the user that it has been updated, while, for instance, a
   YANG Semver version can tell the user about the module's
   compatibility level at a glance.  Having this information available
   as early as possible, i.e. in the module file name, makes it possible
   to quickly identify the module revision; compared to searching in the
   file contents and checking the revisions.  Having the YANG semantic
   version visible in the file name will make it easier to handle large
   sets of YANG modules.

Andersson                Expires 29 August 2025                 [Page 2]
Internet-Draft      YANG module file name convention       February 2025

   The YANG module file name schema described in this draft is already
   deployed in the industry.  Now is the time to standardize before
   several proprietary solutions emerge.  One possibility is to propose
   a standard that gains operational experience.

   Experiments that have updated tooling to handle YANG semantic version
   in the YANG module file name according to this draft have shown that
   it is a relatively small effort to do so.  However, it is recognized
   that the migration of all tooling within the industry will take time.

2.  Module file names

   This section updates Section 5.2 of [RFC7950], Section 5.2 of
   [RFC6020], and Section 3.2 of [RFC8407].

   If a revision has an associated YANG semantic version (ys:version)
   then it MAY use the YANG semantic version instead of the revision
   date in the file name of a YANG file, where it takes the form:

       module-or-submodule-name [['@' revision-date]['#' ys:version]]
           ( '.yang' / '.yin' )

   E.g., acme-router-module@2024-05-15.yang or
   acme-router-module#2.0.3.yang.

   In short, the YANG semantic version file name scheme is recommended
   in order to simplify for module consumers, i.e. to convey
   compatibility status at a glance without needing to read the module.

   YANG module (or submodule) files MAY be identified using either
   revision-date or YANG semantic version (ys:version).  Typically, only
   one file name SHOULD exist for the same module (or submodule)
   revision.  Two file names, one with the revision date and another
   with the YANG semantic version, MAY exist for the same module (or
   submodule) revision, e.g., when migrating from one scheme to the
   other.

2.1.  Coexistence with YANG Semver

   As can be seen above, all valid identifiers for YANG semantic version
   are valid in the filename as well.  Section 4.3 of
   [I-D.ietf-netmod-yang-semver]

   The following example is a valid YANG module file name

       example-module#2.3.1_non_compatible+build2237refM443ss.yang

Andersson                Expires 29 August 2025                 [Page 3]
Internet-Draft      YANG module file name convention       February 2025

   One consequence of this is that there might exist two child modules
   of version 2.0.0 with the same X.Y.Z digits (2.0.1) but different
   version labels:

       2.0.1-draft-superman-super-stuff-03

       2.0.1-draft-batman-cool-addition-07   (a competing draft)

2.2.  Known incompatibilities

   There are currently no known publicly available tools that support
   the YANG semantic version file name schema.  There are known
   proprietary tooling that already uses the file name schema presented
   in this document.

   At the IETF 119 Hackathon, there was a project that investigated the
   feasibility to modify popular YANG tooling to support the proposed
   schema.  There was a successful attempt to modify pyang to support
   the file name schema and also "recommended-min" previously included
   in [I-D.ietf-netmod-yang-module-versioning].  Furthermore, there were
   efforts in researching yanger and libyang to support the schema, but
   the hackathon ended before these projects could be concluded.

3.  Security Considerations

   There are no security considerations for this draft.

4.  References

4.1.  Normative References

   [I-D.ietf-netmod-rfc8407bis]
              Bierman, A., Boucadair, M., and Q. Wu, "Guidelines for
              Authors and Reviewers of Documents Containing YANG Data
              Models", Work in Progress, Internet-Draft, draft-ietf-
              netmod-rfc8407bis-22, 14 January 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netmod-
              rfc8407bis-22>.

   [I-D.ietf-netmod-yang-module-versioning]
              Wilton, R., Rahman, R., Lengyel, B., Clarke, J., and J.
              Sterne, "Updated YANG Module Revision Handling", Work in
              Progress, Internet-Draft, draft-ietf-netmod-yang-module-
              versioning-13, 6 February 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netmod-
              yang-module-versioning-13>.

Andersson                Expires 29 August 2025                 [Page 4]
Internet-Draft      YANG module file name convention       February 2025

   [I-D.ietf-netmod-yang-semver]
              Clarke, J., Wilton, R., Rahman, R., Lengyel, B., Sterne,
              J., and B. Claise, "YANG Semantic Versioning", Work in
              Progress, Internet-Draft, draft-ietf-netmod-yang-semver-
              20, 7 February 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netmod-
              yang-semver-20>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC6020]  Bjorklund, M., Ed., "YANG - A Data Modeling Language for
              the Network Configuration Protocol (NETCONF)", RFC 6020,
              DOI 10.17487/RFC6020, October 2010,
              <https://www.rfc-editor.org/info/rfc6020>.

   [RFC7950]  Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
              RFC 7950, DOI 10.17487/RFC7950, August 2016,
              <https://www.rfc-editor.org/info/rfc7950>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8407]  Bierman, A., "Guidelines for Authors and Reviewers of
              Documents Containing YANG Data Models", BCP 216, RFC 8407,
              DOI 10.17487/RFC8407, October 2018,
              <https://www.rfc-editor.org/info/rfc8407>.

4.2.  Informative References

Acknowledgements

   The author would like to thank Joe Clarke, Reshad Rahman, for their
   excellent technical reviews, support, and guidance.

Author's Address

   Per Andersson
   Cisco Systems
   Email: per.ietf@ionio.se

Andersson                Expires 29 August 2025                 [Page 5]