draft-ietf-netmod-yang-semver-00.txt   draft-ietf-netmod-yang-semver-01.txt 
Network Working Group B. Claise Network Working Group B. Claise
Internet-Draft J. Clarke, Ed. Internet-Draft J. Clarke, Ed.
Intended status: Standards Track R. Rahman Updates: 8407 (if approved) R. Rahman
Expires: September 18, 2020 R. Wilton, Ed. Intended status: Standards Track R. Wilton, Ed.
Cisco Systems, Inc. Expires: January 14, 2021 Cisco Systems, Inc.
B. Lengyel B. Lengyel
Ericsson Ericsson
J. Sterne J. Sterne
Nokia Nokia
K. D'Souza K. D'Souza
AT&T AT&T
March 17, 2020 July 13, 2020
YANG Semantic Versioning YANG Semantic Versioning
draft-ietf-netmod-yang-semver-00 draft-ietf-netmod-yang-semver-01
Abstract Abstract
This document specifies a scheme for applying a modified set of This document specifies a scheme and guidelines for applying a
semantic versioning rules to revisions of YANG modules. modified set of semantic versioning rules to revisions of YANG
Additionally, this document defines a revision label for this modules. Additionally, this document defines a revision-label for
modified semver scheme based on the specification in draft-verdt- this modified semver scheme.
netmod-yang-module-versioning.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 18, 2020. This Internet-Draft will expire on January 14, 2021.
Copyright Notice Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 23 skipping to change at page 2, line 20
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology and Conventions . . . . . . . . . . . . . . . . . 3 2. Terminology and Conventions . . . . . . . . . . . . . . . . . 3
3. YANG Semantic Versioning . . . . . . . . . . . . . . . . . . 3 3. YANG Semantic Versioning . . . . . . . . . . . . . . . . . . 3
3.1. YANG Semantic Versioning Pattern . . . . . . . . . . . . 3 3.1. YANG Semantic Versioning Pattern . . . . . . . . . . . . 3
3.2. Semantic Versioning Scheme for YANG Artifacts . . . . . . 4 3.2. Semantic Versioning Scheme for YANG Artifacts . . . . . . 4
3.2.1. Examples for YANG semantic version numbers . . . . . 6 3.2.1. Examples for YANG semantic version numbers . . . . . 6
3.3. YANG Semantic Version Update Rules . . . . . . . . . . . 7 3.3. YANG Semantic Version Update Rules . . . . . . . . . . . 8
3.4. Examples of the YANG Semver Label . . . . . . . . . . . . 8 3.4. Examples of the YANG Semver Label . . . . . . . . . . . . 9
3.4.1. Example Module Using YANG Semver . . . . . . . . . . 8 3.4.1. Example Module Using YANG Semver . . . . . . . . . . 9
3.4.2. Example of Package Using YANG Semver . . . . . . . . 10 3.4.2. Example of Package Using YANG Semver . . . . . . . . 11
4. Import Module by Semantic Version . . . . . . . . . . . . . . 10 4. Import Module by Semantic Version . . . . . . . . . . . . . . 11
5. YANG Module . . . . . . . . . . . . . . . . . . . . . . . . . 11 5. Guidelines for Using Semver During Module Development . . . . 11
6. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 12 5.1. Pre-release Version Precedence . . . . . . . . . . . . . 13
7. Security Considerations . . . . . . . . . . . . . . . . . . . 13 5.2. YANG Semver in IETF Modules . . . . . . . . . . . . . . . 13
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 6. YANG Module . . . . . . . . . . . . . . . . . . . . . . . . . 13
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 15
9.1. Normative References . . . . . . . . . . . . . . . . . . 13 8. Security Considerations . . . . . . . . . . . . . . . . . . . 16
9.2. Informative References . . . . . . . . . . . . . . . . . 14 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 16
10.1. Normative References . . . . . . . . . . . . . . . . . . 16
10.2. Informative References . . . . . . . . . . . . . . . . . 17
Appendix A. Example IETF Module Development . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 19
1. Introduction 1. Introduction
[I-D.verdt-netmod-yang-module-versioning] puts forth a number of [I-D.ietf-netmod-yang-module-versioning] puts forth a number of
concepts relating to modified rules for updating modules, a means to concepts relating to modified rules for updating modules, a means to
signal when a new revision of a module has non-backwards-compatible signal when a new revision of a module has non-backwards-compatible
(NBC) changes compared to its previous revision, and a versioning (NBC) changes compared to its previous revision, and a versioning
scheme that uses the revision history as a lineage for determining scheme that uses the revision history as a lineage for determining
from where a specific revision of a YANG module is derived. from where a specific revision of a YANG module is derived.
Additionally, section 3.3 of Additionally, section 3.3 of [I-D.ietf-netmod-yang-module-versioning]
[I-D.verdt-netmod-yang-module-versioning] defines a revision label defines a revision label which can be used as an overlay or alias to
which can be used as an overlay or alias to provide additional provide additional context or an additional way to refer to a
context or an additional way to refer to a specific revision. specific revision.
This document defines a labeling scheme that uses modified [semver] This document defines a revision-label scheme that uses modified
rules for YANG artifacts (i.e., YANG modules and YANG packages [semver] rules for YANG artifacts (i.e., YANG modules and YANG
[I-D.rwilton-netmod-yang-packages]) as well as the revision label packages [I-D.ietf-netmod-yang-packages]) as well as the revision
definition for using this scheme. The goal of this is to add a human label definition for using this scheme. The goal of this is to add a
readble version label that provides compatibility information for the human readable version label that provides compatibility information
YANG artifact without one needing to compare or parse its body. The for the YANG artifact without one needing to compare or parse its
label and rules defined herein represent the RECOMMENDED revision body. The label and rules defined herein represent the RECOMMENDED
label scheme for IETF YANG artifacts. revision label scheme for IETF YANG artifacts.
2. Terminology and Conventions 2. Terminology and Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
Additionally, this document uses the following terminology: Additionally, this document uses the following terminology:
o YANG artifact: YANG modules, YANG packages o YANG artifact: YANG modules, YANG packages
[I-D.rwilton-netmod-yang-packages], and YANG schema elements are [I-D.ietf-netmod-yang-packages], and YANG schema elements are
examples of YANG artifacts for the purposes of this document. examples of YANG artifacts for the purposes of this document.
3. YANG Semantic Versioning 3. YANG Semantic Versioning
This section defines YANG Semantic Versioning, explains how it is This section defines YANG Semantic Versioning, explains how it is
used with YANG artifacts, and the rules associated with changing a used with YANG artifacts, and the rules associated with changing an
artifact's semantic version number when its contents are updated. artifact's semantic version number when its contents are updated.
3.1. YANG Semantic Versioning Pattern 3.1. YANG Semantic Versioning Pattern
YANG artifacts that employ semantic versioning MUST use a version YANG artifacts that employ semantic versioning as defined in this
string (e.g., in revision-label or as a package version) that document MUST use a version string (e.g., in revision-label or as a
corresponds to the following pattern: X.Y.Zv. Where: package version) that corresponds to the following pattern:
X.Y.Z_COMPAT. Where:
o X, Y and Z are mandatory non-negative integers that are each less o X, Y and Z are mandatory non-negative integers that are each less
than 32768 and MUST NOT contain leading zeroes than 2147483647 (i.e., the maximum signed 32-bit integer value)
and MUST NOT contain leading zeroes
o The '.' is a literal period (ASCII character 0x2e) o The '.' is a literal period (ASCII character 0x2e)
o v is an optional single character modifier that MUST be either 'm' o The '_' is an optional single literal underscore (ASCII character
or 'M' if it is specified 0x5f) and MUST only present if the following COMPAT element is
included
o COMPAT, if it is specified, MUST be either the literal string
"compatible" or the literal string "non_compatible"
Additionally, [semver] defines two specific types of metadata that Additionally, [semver] defines two specific types of metadata that
may be appended to a semantic version string. Pre-release metadata may be appended to a semantic version string. Pre-release metadata
MAY be appended to a semver string after a trailing '-' character. MAY be appended to a semver string after a trailing '-' character.
Build metadata MAY be appended after a trailing '+' character. If Build metadata MAY be appended after a trailing '+' character. If
both pre-release and build metadata are present, then build metadata both pre-release and build metadata are present, then build metadata
MUST follow pre-release metadata. These optional elements MUST be MUST follow pre-release metadata. While build metadata MUST be
ignored by YANG semver parsers, but are allowed in order to support ignored by YANG semver parsers, pre-release metadata MUST be used
during module development and MUST be considered base on Section 5.
Both pre-release and build metadata are allowed in order to support
all of the [semver] rules. Thus, a version lineage that follows all of the [semver] rules. Thus, a version lineage that follows
strict [semver] rules is allowed for a YANG artifact. strict [semver] rules is allowed for a YANG artifact.
Other version schemes MUST NOT use version strings that match this To signal the use of this versioning scheme, modules MUST set the
same pattern. For example, they may choose to use leading characters revision-label-scheme extension as defined in
to distinguish themselves from YANG semver. [I-D.ietf-netmod-yang-module-versioning] to the identity "yang-
semver". That identity value is defined in the ietf-yang-semver
module below.
A YANG module is defined in this document which contains single Additionally, this ietf-yang-semver module defines a typedef that
typedef that formally specifies this version pattern. formally specifies the syntax of the YANG semver version string.
3.2. Semantic Versioning Scheme for YANG Artifacts 3.2. Semantic Versioning Scheme for YANG Artifacts
This document defines the YANG semantic versioning scheme that is This document defines the YANG semantic versioning scheme that is
used for YANG artifacts that employ the semver label. The versioning used for YANG artifacts that employ the YANG semver label. The
scheme has the following properties: versioning scheme has the following properties:
The YANG semantic versioning scheme is extended from version 2.0.0 The YANG semantic versioning scheme is extended from version 2.0.0
of the semantic versioning scheme defined at semver.org [semver] of the semantic versioning scheme defined at semver.org [semver]
to cover the additional requirements for the management of YANG to cover the additional requirements for the management of YANG
artifact lifecyles that cannot be addressed using the semver.org artifact lifecyles that cannot be addressed using the semver.org
2.0.0 versioning scheme alone. 2.0.0 versioning scheme alone.
Unlike the [semver] versioning scheme, the YANG semantic Unlike the [semver] versioning scheme, the YANG semantic
versioning scheme supports limited updates to older versions of versioning scheme supports limited updates to older versions of
YANG artifacts, to allow for bug fixes and enhancements to YANG artifacts, to allow for bug fixes and enhancements to
artifact versions that are not the latest. However, it does not artifact versions that are not the latest. However, it does not
provide for the unlimited branching and updating of older provide for the unlimited branching and updating of older
revisions which are documented by the general rules in revisions which are documented by the general rules in
[I-D.verdt-netmod-yang-module-versioning]. [I-D.ietf-netmod-yang-module-versioning].
YANG artifacts that follow the [semver] versioning scheme are YANG artifacts that follow the [semver] versioning scheme are
fully compatible with implementations that understand the YANG fully compatible with implementations that understand the YANG
semantic versioning scheme defined in this document. semantic versioning scheme defined in this document.
If updates are always restricted to the latest revision of the If updates are always restricted to the latest revision of the
artifact only, then the version numbers used by the YANG semantic artifact only, then the version numbers used by the YANG semantic
versioning scheme are exactly the same as those defined by the versioning scheme are exactly the same as those defined by the
[semver] versioning scheme. [semver] versioning scheme.
Every YANG module versioned using the YANG semantic versioning scheme Every YANG module versioned using the YANG semantic versioning scheme
specifies the module's semantic version number as the argument to the specifies the module's semantic version number as the argument to the
'rev:revision-label' statement. 'rev:revision-label' statement.
Because the rules put forth in Because the rules put forth in
[I-D.verdt-netmod-yang-module-versioning] are designed to work well [I-D.ietf-netmod-yang-module-versioning] are designed to work well
with existing versions of YANG and allow for artifact authors to with existing versions of YANG and allow for artifact authors to
migrate to this scheme, it is not expected that all revisions of a migrate to this scheme, it is not expected that all revisions of a
given YANG artifact will have a semantic version label. For example, given YANG artifact will have a semantic version label. For example,
the first revision of a module may have been produced before this the first revision of a module may have been produced before this
scheme was available. scheme was available.
YANG packages that make use of this semantic versioning scheme will YANG packages that make use of this semantic versioning scheme will
have their semantic version as the value of the "revision_label" have their semantic version as the value of the "revision_label"
property. property.
As stated above, the YANG semver version number is expressed as a As stated above, the YANG semver version number is expressed as a
string of the form: 'X.Y.Zv'; where X, Y, and Z each represent non- string of the form: 'X.Y.Z_COMPAT'; where X, Y, and Z each represent
negative integers smaller than 32768 without leading zeroes, and v non-negative integers smaller than 2147483647 without leading zeroes,
represents an optional single character suffix: 'm' or 'M'. and _COMPAT represents an optional suffix of either "_compatible" or
"_non_compatible".
o 'X' is the MAJOR version. Changes in the major version number o 'X' is the MAJOR version. Changes in the major version number
indicate changes that are non-backwards-compatible to versions indicate changes that are non-backwards-compatible to versions
with a lower major version number. with a lower major version number.
o 'Y' is the MINOR version. Changes in the minor version number o 'Y' is the MINOR version. Changes in the minor version number
indicate changes that are backwards-compatible to versions with indicate changes that are backwards-compatible to versions with
the same major version number, but a lower minor version number the same major version number, but a lower minor version number
and no patch 'm' or 'M' modifier. and no patch "_compatible" or "_non_compatible" modifier.
o 'Zv' is the PATCH version and modifier. Changes in the patch o 'Z_COMPAT' is the PATCH version and modifier. Changes in the
version number can indicate editorial, backwards-compatible, or patch version number can indicate editorial, backwards-compatible,
non-backwards-compatible changes relative to versions with the or non-backwards-compatible changes relative to versions with the
same major and minor version numbers, but lower patch version same major and minor version numbers, but lower patch version
number, depending on what form modifier 'v' takes: number, depending on what form modifier "_COMPAT" takes:
* If the modifier letter is absent, the change represents an * If the modifier string is absent, the change represents an
editorial change. An editorial change is defined to be a editorial change. An editorial change is defined to be a
change in the YANG artifact's content that does not affect the change in the YANG artifact's content that does not affect the
semantic meaning or functionality provided by the artifact in semantic meaning or functionality provided by the artifact in
any way. An example is correcting a spelling mistake in the any way. An example is correcting a spelling mistake in the
description of a leaf within a YANG module. Note: description of a leaf within a YANG module. Note:
restructuring how a module uses, or does not use, submodules is restructuring how a module uses, or does not use, submodules is
treated as an editorial level change on the condition that treated as an editorial level change on the condition that
there is no change in the module's semantic behavior due to the there is no change in the module's semantic behavior due to the
restructuring. restructuring.
* If, however, the modifier letter is present, the meaning is * If, however, the modifier string is present, the meaning is
described below: described below:
* 'm' - the change represents a backwards-compatible change * "_compatible" - the change represents a backwards-compatible
change
* 'M' - the change represents a non-backwards-compatible change * "_non_compatible" - the change represents a non-backwards-
compatible change
The YANG articact name and YANG semantic version number uniquely The YANG artifact name and YANG semantic version number uniquely
identifies a revision of said artifact. There MUST NOT be multiple identify a revision of said artifact. There MUST NOT be multiple
instances of a YANG artifact definition with the same name and YANG instances of a YANG artifact definition with the same name and YANG
semantic version number but different content (and in the case of semantic version number but different content (and in the case of
modules, different revision dates). modules, different revision dates).
There MUST NOT be multiple versions of a YANG artifact that have the There MUST NOT be multiple versions of a YANG artifact that have the
same MAJOR, MINOR and PATCH version numbers, but different patch same MAJOR, MINOR and PATCH version numbers, but different patch
modifier letters. E.g., artifact version "1.2.3M" MUST NOT be modifier strings. E.g., artifact version "1.2.3_non_compatible" MUST
defined if artifact version "1.2.3" has already been defined. NOT be defined if artifact version "1.2.3" has already been defined.
3.2.1. Examples for YANG semantic version numbers 3.2.1. Examples for YANG semantic version numbers
The following diagram and explanation illustrates how YANG semantic The following diagram and explanation illustrates how YANG semantic
version numbers work. version numbers work.
Example YANG semantic version numbers for an example artifact: Example YANG semantic version numbers for an example artifact:
0.1.0 0.1.0
| |
0.2.0 0.2.0
| |
1.0.0 1.0.0
| \ | \
| 1.1.0 -> 1.1.1m -> 1.1.2M | 1.1.0 -> 1.1.1_compatible -> 1.1.2_non_compatible
| | | |
| 1.2.0 -> 1.2.1M -> 1.2.2M | 1.2.0 -> 1.2.1_non_compatible -> 1.2.2_non_compatible
| | | |
| 1.3.0 -> 1.3.1 | 1.3.0 -> 1.3.1
| |
2.0.0 2.0.0
| |
3.0.0 3.0.0
\ \
3.1.0 3.1.0
Assume the tree diagram above illustrates how an example YANG Assume the tree diagram above illustrates how an example YANG
skipping to change at page 7, line 4 skipping to change at page 7, line 19
0.1.0 - first beta module version 0.1.0 - first beta module version
0.2.0 - second beta module version (with NBC changes) 0.2.0 - second beta module version (with NBC changes)
1.0.0 - first release (may have NBC changes from 0.2.0) 1.0.0 - first release (may have NBC changes from 0.2.0)
1.1.0 - added new functionality, leaf "foo" (BC) 1.1.0 - added new functionality, leaf "foo" (BC)
1.2.0 - added new functionality, leaf "baz" (BC) 1.2.0 - added new functionality, leaf "baz" (BC)
1.3.0 - improve existing functionality, added leaf "foo-64" (BC) 1.3.0 - improve existing functionality, added leaf "foo-64" (BC)
1.3.1 - improve description wording for "foo-64" (Editorial) 1.3.1 - improve description wording for "foo-64" (Editorial)
1.1.1m - backport "foo-64" leaf to 1.1.x to avoid implementing 1.1.1_compatible - backport "foo-64" leaf to 1.1.x to avoid
"baz" from 1.2.0 (BC) implementing "baz" from 1.2.0 (BC)
2.0.0 - change existing model for performance reasons, e.g. re-key 2.0.0 - change existing model for performance reasons, e.g. re-key
list (NBC) list (NBC)
1.1.2M - NBC point bug fix, not required in 2.0.0 due to model 1.1.2_non_compatible - NBC point bug fix, not required in 2.0.0
changes (NBC) due to model changes (NBC)
3.0.0 - NBC bugfix, rename "baz" to "bar"; also add new BC leaf 3.0.0 - NBC bugfix, rename "baz" to "bar"; also add new BC leaf
"wibble"; (NBC) "wibble"; (NBC)
1.2.1M - backport NBC fix, changing "baz" to "bar" 1.2.1_non_compatible - backport NBC fix, changing "baz" to "bar"
1.2.2M - backport "wibble". This is a BC change but "M" modifier 1.2.2_non_compatible - backport "wibble". This is a BC change but
is sticky. "non_compatible" modifier is sticky.
3.1.0 - introduce new leaf "wobble" (BC) 3.1.0 - introduce new leaf "wobble" (BC)
The partial ordering relationships based on the semantic versioning The partial ordering relationships based on the semantic versioning
numbers can be defined as follows: numbers can be defined as follows:
1.0.0 < 1.1.0 < 1.2.0 < 1.3.0 < 2.0.0 < 3.0.0 < 3.1.0 1.0.0 < 1.1.0 < 1.2.0 < 1.3.0 < 2.0.0 < 3.0.0 < 3.1.0
1.0.0 < 1.1.0 < 1.1.1m < 1.1.2M 1.0.0 < 1.1.0 < 1.1.1_compatible < 1.1.2_non_compatible
1.0.0 < 1.1.0 < 1.2.0 < 1.2.1M < 1.2.2M 1.0.0 < 1.1.0 < 1.2.0 < 1.2.1_non_compatible <
1.2.2_non_compatible
There is no ordering relationship between 1.1.1M and either 1.2.0 or There is no ordering relationship between 1.1.1_non_compatible and
1.2.1M, except that they share the common ancestor of 1.1.0. either 1.2.0 or 1.2.1_non_compatible, except that they share the
common ancestor of 1.1.0.
Looking at the version number alone, the module definition in 2.0.0 Looking at the version number alone, the module definition in 2.0.0
does not necessarily contain the contents of 1.3.0. However, the does not necessarily contain the contents of 1.3.0. However, the
module revision history in 2.0.0 may well indicate that it was edited module revision history in 2.0.0 may well indicate that it was edited
from module version 1.3.0. from module version 1.3.0.
3.3. YANG Semantic Version Update Rules 3.3. YANG Semantic Version Update Rules
When a new revision of an artifact is produced, then the following When a new revision of an artifact is produced, then the following
rules define how the YANG semantic version number for the new rules define how the YANG semantic version number for the new
artifact revision is calculated, based on the changes between the two artifact revision is calculated, based on the changes between the two
artifact revisions, and the YANG semantic version number of the base artifact revisions, and the YANG semantic version number of the base
artifact revision from which the changes are derived: artifact revision from which the changes are derived:
1. If an artifact is being updated in a non-backwards-compatible 1. If an artifact is being updated in a non-backwards-compatible
way, then the artifact version "X.Y.Z[m|M]" MUST be updated to way, then the artifact version
"X+1.0.0" unless that artifact version has already been defined "X.Y.Z[_compatible|_non_compatible]" MUST be updated to "X+1.0.0"
with different content, in which case the artifact version unless that artifact version has already been defined with
"X.Y.Z+1M" MUST be used instead. different content, in which case the artifact version
"X.Y.Z+1_non_compatible" MUST be used instead.
2. If an artifact is being updated in a backwards-compatible way, 2. Under some circumstances (e.g., to avoid adding a "_compatible"
modifier) an artifact author MAY also update the MAJOR version
when the only changes are backwards-compatible. This is where
tooling is important to highlight all changes. Because, while
avoiding the "_compatible" and "_non_compatible" modifiers have a
clear advantage, bumping a MAJOR version when changes are
entirely backwards-compatible may confuse end users.
3. If an artifact is being updated in a backwards-compatible way,
then the next version number depends on the format of the current then the next version number depends on the format of the current
version number: version number:
i "X.Y.Z" - the artifact version MUST be updated to i "X.Y.Z" - the artifact version MUST be updated to
"X.Y+1.0", unless that artifact version has already been "X.Y+1.0", unless that artifact version has already been
defined with different content, when the artifact version defined with different content, when the artifact version
MUST be updated to "X.Y.Z+1m" instead. MUST be updated to "X.Y.Z+1_compatible"" instead.
ii "X.Y.Zm" - the artifact version MUST be updated to ii "X.Y.Z_compatible" - the artifact version MUST be updated
"X.Y.Z+1m". to "X.Y.Z+1_compatible".
iii "X.Y.ZM" - the artifact version MUST be updated to iii "X.Y.Z_non_compatible" - the artifact version MUST be
"X.Y.Z+1M". updated to "X.Y.Z+1_non_compatible".
3. If an artifact is being updated in an editorial way, then the 4. If an artifact is being updated in an editorial way, then the
next version number depends on the format of the current version next version number depends on the format of the current version
number: number:
i "X.Y.Z" - the artifact version MUST be updated to "X.Y.Z+1" i "X.Y.Z" - the artifact version MUST be updated to "X.Y.Z+1"
ii "X.Y.Zm" - the artifact version MUST be updated to ii "X.Y.Z_compatible" - the artifact version MUST be updated
"X.Y.Z+1m". to "X.Y.Z+1_compatible".
iii "X.Y.ZM" - the artifact version MUST be updated to iii "X.Y.Z_non_compatible" - the artifact version MUST be
"X.Y.Z+1M". updated to "X.Y.Z+1_non_compatible".
4. YANG artifact semantic version numbers beginning with 0, i.e 5. YANG artifact semantic version numbers beginning with 0, i.e
"0.X.Y" are regarded as beta definitions and need not follow the "0.X.Y" are regarded as beta definitions and need not follow the
rules above. Either the MINOR or PATCH version numbers may be rules above. Either the MINOR or PATCH version numbers may be
updated, regardless of whether the changes are non-backwards- updated, regardless of whether the changes are non-backwards-
compatible, backwards-compatible, or editorial. compatible, backwards-compatible, or editorial. See Section 5
for more details on using this notation during module
development.
3.4. Examples of the YANG Semver Label 3.4. Examples of the YANG Semver Label
3.4.1. Example Module Using YANG Semver 3.4.1. Example Module Using YANG Semver
Below is a sample YANG module that uses the YANG semver revision Below is a sample YANG module that uses the YANG semver revision
label based on the rules defined in this document. label based on the rules defined in this document.
module yang-module-name { module example-versioned-module {
namespace "name-space"; yang-version 1.1;
prefix "prefix-name"; namespace "urn:example:versioned:module";
prefix "exvermod";
rev:revision-label-scheme "yangver:yang-semver";
import ietf-yang-revisions { prefix "rev"; } import ietf-yang-revisions { prefix "rev"; }
import ietf-yang-semver { prefix "yangver"; }
description description
"to be completed"; "to be completed";
revision 2018-02-28 { revision 2018-02-28 {
description "Added leaf 'wobble'"; description "Added leaf 'wobble'";
rev:revision-label "3.1.0"; rev:revision-label "3.1.0";
} }
revision 2017-12-31 { revision 2017-12-31 {
skipping to change at page 10, line 41 skipping to change at page 11, line 25
"description": "Example IETF package definition", "description": "Example IETF package definition",
"content-data": { "content-data": {
"ietf-yang-package:yang-package": { "ietf-yang-package:yang-package": {
"name": "example-yang-pkg", "name": "example-yang-pkg",
"version": "1.3.1", "version": "1.3.1",
... ...
} }
4. Import Module by Semantic Version 4. Import Module by Semantic Version
[I-D.verdt-netmod-yang-module-versioning] allows for imports to be [I-D.ietf-netmod-yang-module-versioning] allows for imports to be
done based on a module or a derived revision of a module. The done based on a module or a derived revision of a module. The
rev:revision-or-derived statement can specify either a revision date rev:revision-or-derived statement can specify either a revision date
or a revision label. When importing by semver, the YANG semver or a revision label. When importing by semver, the YANG semver
revision label value MAY be used as an argument to rev:revision-or- revision label value MAY be used as an argument to rev:revision-or-
derived. In so, any module which has that semver label as its latest derived. In so, any module which has that semver label as its latest
revision label or has that label in its revision history can be used revision label or has that label in its revision history can be used
to satisfy the import requirement. For example: to satisfy the import requirement. For example:
import example-module { import example-module {
rev:revision-or-derived "3.0.0"; rev:revision-or-derived "3.0.0";
} }
Note: the import lookup does not stop when a non-backward-compatible Note: the import lookup does not stop when a non-backward-compatible
change is encountered. That is, if module B imports a module A at or change is encountered. That is, if module B imports a module A at or
derived from version 2.0.0, resolving that import will pass through a derived from version 2.0.0, resolving that import will pass through a
revision of module A with version 2.1.0M in order to determine if the revision of module A with version 2.1.0_non_compatible in order to
present instance of module A derives from 2.0.0. determine if the present instance of module A derives from 2.0.0.
5. YANG Module 5. Guidelines for Using Semver During Module Development
This section and the IETF-specific sub-section below provides YANG
semver-specific guidelines to consider when developing new YANG
modules. As such this section updates [RFC8407].
Development of a brand new YANG module outside of the IETF that uses
YANG semver as its revision-label scheme SHOULD begin with a 0 for
the MAJOR version component. This allows the module to disregard
strict semver rules with respect to non-backwards-compatible changes
during its initial development. However, module developers MAY
choose to use the semver pre-release syntax instead with a 1 for the
MAJOR version component. For example, an initial module revision-
label might be either 0.0.1 or 1.0.0-alpha.1. If the authors choose
to use the 0 MAJOR version component scheme, they MAY switch to the
pre-release scheme with a MAJOR version component of 1 when the
module is nearing initial release (e.g., a module's revision label
may transition from 0.3.0 to 1.0.0-beta.1 to indicate it is more
mature and ready for testing).
When using pre-release notation, the format MUST include at least one
alphabetic component and MUST end with a '.' and then one or more
digits. These alphanumeric components will be used when deciding
pre-release precedence. The following are examples of valid pre-
release versions
1.0.0-alpha.1
1.0.0-alpha.3
2.1.0-beta.42
3.0.0-202007.rc.1
When developing a new revision of an existing module using the YANG
semver revision-label scheme, the intended target semver version MUST
be used along with pre-release notation. For example, if a released
module which has a current revision-label of 1.0.0 is being modified
with the intent to make non-backwards-compatible changes, the first
development MAJOR version component must be 2 with some pre-release
notation such as -alpha.1, making the version 2.0.0-alpha.1. That
said, every publicly available release of a module MUST have a unique
YANG semver revision-label (where a publicly available release is one
that could be implemented by a vendor or consumed by an end user).
Therefore, it may be prudent to include the year or year and month
development began (e.g., 2.0.0-201907-alpha.1). As a module
undergoes development, it is possible that the original intent
changes. For example, a 1.0.0 version of a module that was destined
to become 2.0.0 after a development cycle may have had a scope change
such that the final version has no non-backwards-compatible changes
and becomes 1.1.0 instead. This change is acceptable to make during
the development phase so long as pre-release notation is present in
both versions (e.g., 2.0.0-alpha.3 becomes 1.1.0-alpha.4). However,
on the next development cycle (after 1.1.0 is released), if again the
new target release is 2.0.0, new pre-release components must be used
such that every revision-label for a given module MUST be unique
throughout its entire lifecycle (e.g., the first pre-release version
might be 2.0.0-202005-alpha.1 if keeping the same year and month
notation mentioned above).
5.1. Pre-release Version Precedence
[TODO: Describe precedence considering there could be changes during
development and parallel development tracks.]
5.2. YANG Semver in IETF Modules
Net new module development within the IETF SHOULD begin with the 0
MAJOR number scheme as described above. When revising an existing
IETF module, the revision-label MUST use the target (i.e., intended)
MAJOR and MINOR version components with a 0 patch version component.
If the intended ratified release will be non-backward-compatible with
the current ratified release, the MINOR version component MUST be 0.
All IETF modules in development MUST use the whole document name as a
pre-release version string, including the current document revision.
For example, if a module which is currently released at version 1.0.0
is being revised to include non-backwards-compatible changes in
draft-user-netmod-foo, its development revision-labels MUST include
2.0.0-draft-user-netmod-foo followed by the document's revision
(e.g., 2.0.0-draft-user-netmod-foo-02). This will ensure each pre-
release version is unique across the lifecycle of the module. Even
when using the 0 MAJOR version for initial module development (where
MINOR and PATCH can change), appending the draft name as a pre-
release component helps to ensure uniqueness when there are perhaps
multiple, parallel efforts creating the same module.
If a module is being revised and the original module never had a
revision-label (i.e., you wish to start using YANG semver in future
module revisions), choose a semver value that makes the most sense
based on the module's history. For example, if a module started out
in the pre-NMDA ([RFC8342]) world, and then had NMDA support added
without removing any legacy "state" branches -- and you are looking
to add additional new features -- a sensible choice for the target
YANG semver would be 1.2.0 (since 1.0.0 would have been the initial,
pre-NMDA release, and 1.1.0 would have been the NMDA revision).
See Appendix A for a detailed example of IETF pre-release versions.
6. YANG Module
This YANG module contains the typedef for the YANG semantic version. This YANG module contains the typedef for the YANG semantic version.
<CODE BEGINS> file "ietf-yang-semver@2019-09-06.yang" <CODE BEGINS> file "ietf-yang-semver@2019-09-06.yang"
module ietf-yang-semver { module ietf-yang-semver {
yang-version 1.1; yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-yang-semver"; namespace "urn:ietf:params:xml:ns:yang:ietf-yang-semver";
prefix yangver; prefix yangver;
rev:revision-label-scheme "yang-semver";
import ietf-yang-revisions {
prefix rev;
}
organization organization
"IETF NETMOD (Network Modeling) Working Group"; "IETF NETMOD (Network Modeling) Working Group";
contact contact
"WG Web: <http://tools.ietf.org/wg/netmod/> "WG Web: <http://tools.ietf.org/wg/netmod/>
WG List: <mailto:netmod@ietf.org> WG List: <mailto:netmod@ietf.org>
Author: Joe Clarke Author: Joe Clarke
<mailto:jclarke@cisco.com>"; <mailto:jclarke@cisco.com>";
description description
"This module provides type and grouping definitions for YANG "This module provides type and grouping definitions for YANG
packages. packages.
Copyright (c) 2019 IETF Trust and the persons identified as Copyright (c) 2020 IETF Trust and the persons identified as
authors of the code. All rights reserved. authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject without modification, is permitted pursuant to, and subject
to the license terms contained in, the Simplified BSD License to the license terms contained in, the Simplified BSD License
set forth in Section 4.c of the IETF Trust's Legal Provisions set forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents Relating to IETF Documents
(http://trustee.ietf.org/license-info). (http://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX; see This version of this YANG module is part of RFC XXXX; see
the RFC itself for full legal notices."; the RFC itself for full legal notices.";
// RFC Ed.: update the date below with the date of RFC publication // RFC Ed.: update the date below with the date of RFC publication
// and remove this note. // and remove this note.
// RFC Ed.: replace XXXX with actual RFC number and remove this // RFC Ed.: replace XXXX with actual RFC number and remove this
// note. // note.
revision 2019-09-06 { revision 2020-06-30 {
rev:revision-label "1.0.0-draft-ietf-netmod-yang-semver-01";
description description
"Initial revision"; "Initial revision";
reference reference
"RFC XXXX: YANG Semantic Versioning."; "RFC XXXX: YANG Semantic Versioning.";
} }
/*
* Identities
*/
identity yang-semver {
base rev:revision-label-scheme-base-identity;
description
"The revision-label scheme corresponds to the YANG semver scheme
which is defined by the pattern in the 'version' typedef below.
The rules governing this revision-label scheme are defined in the
reference for this identity.";
reference
"RFC XXXX: YANG Semantic Versioning.";
}
/* /*
* Typedefs * Typedefs
*/ */
typedef version { typedef version {
type string { type string {
pattern '\d+[.]\d+[.]\d+[mM]?(-[\w\d.]+)?([+][\w\d\.]+)?'; pattern '\d+[.]\d+[.]\d+(_(non_)?compatible)?(-[\w\d.]+)?([+][\w\d\.]+)?';
} }
description description
"Represents a YANG semantic version number. Note: "Represents a YANG semantic version number. The rules governing the
additional rules apply to the dot-separated numeric identifiers use of this revision label scheme are defined in the reference for
which are spelled out in the reference for this typedef."; this typedef.";
reference reference
"RFC XXXX: YANG Semantic Versioning."; "RFC XXXX: YANG Semantic Versioning.";
} }
} }
<CODE ENDS> <CODE ENDS>
6. Contributors 7. Contributors
This document grew out of the YANG module versioning design team that This document grew out of the YANG module versioning design team that
started after IETF 101. The design team consists of the following started after IETF 101. The design team consists of the following
members whom have worked on the YANG versioning project: members whom have worked on the YANG versioning project:
o Balazs Lengyel o Balazs Lengyel
o Benoit Claise o Benoit Claise
o Ebben Aries o Ebben Aries
skipping to change at page 13, line 16 skipping to change at page 16, line 26
o Rob Wilton o Rob Wilton
The initial revision of this document was refactored and built upon The initial revision of this document was refactored and built upon
[I-D.clacla-netmod-yang-model-update]. [I-D.clacla-netmod-yang-model-update].
Discussons on the use of Semver for YANG versioning has been held Discussons on the use of Semver for YANG versioning has been held
with authors of the OpenConfig YANG models based on their own with authors of the OpenConfig YANG models based on their own
[openconfigsemver]. We would like thank both Anees Shaikh and Rob [openconfigsemver]. We would like thank both Anees Shaikh and Rob
Shakir for their input into this problem space. Shakir for their input into this problem space.
7. Security Considerations 8. Security Considerations
The document does not define any new protocol or data model. There The document does not define any new protocol or data model. There
are no security impacts. are no security impacts.
8. IANA Considerations 9. IANA Considerations
None. None.
9. References 10. References
9.1. Normative References 10.1. Normative References
[I-D.verdt-netmod-yang-module-versioning] [I-D.ietf-netmod-yang-module-versioning]
Claise, B., Clarke, J., Rahman, R., Wilton, R., Lengyel, Claise, B., Clarke, J., Rahman, R., Wilton, R., Lengyel,
B., Sterne, J., and K. D'Souza, "Updated YANG Module B., Sterne, J., and K. D'Souza, "Updated YANG Module
Revision Handling", draft-verdt-netmod-yang-module- Revision Handling", draft-ietf-netmod-yang-module-
versioning-01 (work in progress), October 2019. versioning-00 (work in progress), March 2020.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC7895] Bierman, A., Bjorklund, M., and K. Watsen, "YANG Module
Library", RFC 7895, DOI 10.17487/RFC7895, June 2016,
<https://www.rfc-editor.org/info/rfc7895>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8525] Bierman, A., Bjorklund, M., Schoenwaelder, J., Watsen, K., [RFC8407] Bierman, A., "Guidelines for Authors and Reviewers of
and R. Wilton, "YANG Library", RFC 8525, Documents Containing YANG Data Models", BCP 216, RFC 8407,
DOI 10.17487/RFC8525, March 2019, DOI 10.17487/RFC8407, October 2018,
<https://www.rfc-editor.org/info/rfc8525>. <https://www.rfc-editor.org/info/rfc8407>.
9.2. Informative References 10.2. Informative References
[I-D.clacla-netmod-yang-model-update] [I-D.clacla-netmod-yang-model-update]
Claise, B., Clarke, J., Lengyel, B., and K. D'Souza, "New Claise, B., Clarke, J., Lengyel, B., and K. D'Souza, "New
YANG Module Update Procedure", draft-clacla-netmod-yang- YANG Module Update Procedure", draft-clacla-netmod-yang-
model-update-06 (work in progress), July 2018. model-update-06 (work in progress), July 2018.
[I-D.ietf-netmod-yang-instance-file-format] [I-D.ietf-netmod-yang-packages]
Lengyel, B. and B. Claise, "YANG Instance Data File
Format", draft-ietf-netmod-yang-instance-file-format-08
(work in progress), March 2020.
[I-D.rwilton-netmod-yang-packages]
Wilton, R., Rahman, R., Clarke, J., Sterne, J., and W. Bo, Wilton, R., Rahman, R., Clarke, J., Sterne, J., and W. Bo,
"YANG Packages", draft-rwilton-netmod-yang-packages-03 "YANG Packages", draft-ietf-netmod-yang-packages-00 (work
(work in progress), February 2020. in progress), March 2020.
[openconfigsemver] [openconfigsemver]
"Semantic Versioning for Openconfig Models", "Semantic Versioning for Openconfig Models",
<http://www.openconfig.net/docs/semver/>. <http://www.openconfig.net/docs/semver/>.
[RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
and R. Wilton, "Network Management Datastore Architecture
(NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
<https://www.rfc-editor.org/info/rfc8342>.
[semver] "Semantic Versioning 2.0.0", <https://www.semver.org>. [semver] "Semantic Versioning 2.0.0", <https://www.semver.org>.
Appendix A. Example IETF Module Development
Assume a new YANG module is being developed in the netmod working
group in the IETF. Initially, this module is being developed in an
individual internet draft, draft-jdoe-netmod-example-module. The
following represents the initial version tree (i.e., value of
revision-label) of the module as it's being initially developed.
Version lineage for initial module development:
0.0.1-draft-jdoe-netmod-example-module-00
|
0.1.0-draft-jdoe-netmod-example-module-01
|
0.2.0-draft-jdoe-netmod-example-module-02
|
0.2.1-draft-jdoe-netmod-example-module-03
At this point, development stabilizes, and the workgroup adopts the
draft. Thus now the draft becomes draft-ietf-netmod-example-module.
The initial pre-release lineage continues as follows.
Continued version lineage after adoption:
1.0.0-draft-ietf-netmod-example-module-00
|
1.0.0-draft-ietf-netmod-example-module-01
|
1.0.0-draft-ietf-netmod-example-module-02
At this point, the draft is ratified and becomes RFC12345 and the
YANG module version number becomes 1.0.0.
A time later, the module needs to be revised to add additional
capabilities. Development will be done in a backwards-compatible
way. Two new individual drafts are proposed to go about adding the
capabilities in different ways: draft-jdoe-netmod-exmod-enhancements
and draft-jadoe-netmod-exmod-changes. These are initially developed
in parallel with the following versions.
Parallel development for next module revision:
1.1.0-draft-jdoe-netmod-exmod-enhancements-00 || 1.1.0-draft-jadoe-netmod-exmod-changes-00
| |
1.1.0-draft-jdoe-netmod-exmod-enhancements-01 || 1.1.0-draft-jadoe-netmod-exmod-changes-01
At this point, the WG decides to merge some aspects of both and adopt
the work in jadoe's draft as draft-ietf-netmod-exmod-changes. A
single version lineage continues.
1.1.0-draft-ietf-netmod-exmod-changes-00
|
1.1.0-draft-ietf-netmod-exmod-changes-01
|
1.1.0-draft-ietf-netmod-exmod-changes-02
|
1.1.0-draft-ietf-netmod-exmod-changes-03
The draft is ratified, and the new module version becomes 1.1.0.
Authors' Addresses Authors' Addresses
Benoit Claise Benoit Claise
Cisco Systems, Inc. Cisco Systems, Inc.
De Kleetlaan 6a b1 De Kleetlaan 6a b1
1831 Diegem 1831 Diegem
Belgium Belgium
Phone: +32 2 704 5622 Phone: +32 2 704 5622
Email: bclaise@cisco.com Email: bclaise@cisco.com
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