Internet DRAFT - draft-ietf-netconf-list-pagination-rc
draft-ietf-netconf-list-pagination-rc
NETCONF Working Group K. Watsen
Internet-Draft Watsen Networks
Updates: 8040 (if approved) Q. Wu
Intended status: Standards Track Huawei Technologies
Expires: 2 September 2024 O. Hagsand
SUNET
H. Li
Hewlett Packard Enterprise
P. Andersson
Cisco Systems
1 March 2024
RESTCONF Extensions to Support List Pagination
draft-ietf-netconf-list-pagination-rc-03
Abstract
This document defines a mapping of the list pagination mechanism
defined in [I-D.ietf-netconf-list-pagination] to RESTCONF [RFC8040].
This document updates RFC 8040, to declare "list" and "leaf-list" as
valid resource targets for the RESTCONF GET and DELETE operations, to
define GET query parameters necessary for list pagination, and to
define a media-type for XML-based lists.
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 2 September 2024.
Copyright Notice
Copyright (c) 2024 IETF Trust and the persons identified as the
document authors. All rights reserved.
Watsen, et al. Expires 2 September 2024 [Page 1]
Internet-Draft RESTCONF Pagination Support March 2024
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. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Conventions . . . . . . . . . . . . . . . . . . . . . . . 3
2. Updates to RFC 8040 . . . . . . . . . . . . . . . . . . . . . 3
2.1. Resource Targets . . . . . . . . . . . . . . . . . . . . 3
2.2. Media Type . . . . . . . . . . . . . . . . . . . . . . . 3
2.3. Query Parameters . . . . . . . . . . . . . . . . . . . . 4
2.3.1. The "limit" Query Parameter . . . . . . . . . . . . . 6
2.3.2. The "offset" Query Parameter . . . . . . . . . . . . 6
2.3.3. The "cursor" Query Parameter . . . . . . . . . . . . 6
2.3.4. The "direction" Query Parameter . . . . . . . . . . . 7
2.3.5. The "sort-by" Query Parameter . . . . . . . . . . . . 7
2.3.6. The "locale" Query Parameter . . . . . . . . . . . . 7
2.3.7. The "where" Query Parameter . . . . . . . . . . . . . 7
2.3.8. The "sublist-limit" Query Parameter . . . . . . . . . 8
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
3.1. The "RESTCONF Capability URNs" Registry . . . . . . . . . 8
3.2. The "Media Types" Registry . . . . . . . . . . . . . . . 8
3.2.1. Media Type "application/yang-data+xml-list" . . . . . 8
4. Security Considerations . . . . . . . . . . . . . . . . . . . 10
5. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
5.1. Normative References . . . . . . . . . . . . . . . . . . 10
5.2. Informative References . . . . . . . . . . . . . . . . . 10
Appendix A. Example YANG Module . . . . . . . . . . . . . . . . 11
Appendix B. Example Data Set . . . . . . . . . . . . . . . . . . 11
Appendix C. Example Queries . . . . . . . . . . . . . . . . . . 11
C.1. List pagination with all query parameters . . . . . . . . 11
C.2. Deletion of a leaf-list . . . . . . . . . . . . . . . . . 13
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13
1. Introduction
This document defines a mapping of the list pagination mechanism
defined in [I-D.ietf-netconf-list-pagination] to RESTCONF [RFC8040].
This document updates RFC 8040, as described in Section 2.
Watsen, et al. Expires 2 September 2024 [Page 2]
Internet-Draft RESTCONF Pagination Support March 2024
Declaring "list" and "leaf-list" as valid resource targets for the
GET operation is necessary for list pagination. Declaring these
nodes as valid resource targets for the DELETE operation merely
completes the solution for RESTCONF.
1.1. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
1.2. Conventions
Various examples in this document use "BASE64VALUE=" as a placeholder
value for binary data that has been base64 encoded (per Section 9.8
of [RFC7950]). This placeholder value is used because real base64
encoded structures are often many lines long and hence distracting to
the example being presented.
2. Updates to RFC 8040
2.1. Resource Targets
This document extends Section 3.5 of [RFC8040] to add "list" and
"leaf-list" nodes (not just their entries) as valid data resources
for the "GET" and "DELETE" operations.
2.2. Media Type
This document extends Section 3.2 of [RFC8040] to add a new media
type, "application/yang-data+xml-list", to encode "list" and "leaf-
list" nodes in XML.
The "application/yang-data+xml-list" media-type defines a pseudo top-
level element called "xml-list" that is used to wrap the response
set, thus ensuring that a single top-level element is returned for
the XML encoding", as required by Section 4.3 of [RFC8040].
For JSON, the existing "application/yang-data+json" media type is
sufficient, as the JSON format has built-in support for encoding
arrays.
The "application/yang-data+xml-list" media type is registered in
Section 3.2.1.
Watsen, et al. Expires 2 September 2024 [Page 3]
Internet-Draft RESTCONF Pagination Support March 2024
2.3. Query Parameters
This document extends Section 4.8 of [RFC8040] to add new query
parameters "limit", "offset", "cursor", "direction", "sort-by",
"locale", "where", and "sublist-list".
These six query parameters correspond to those defined in Sections
3.1 and 3.2 in [I-D.ietf-netconf-list-pagination].
Watsen, et al. Expires 2 September 2024 [Page 4]
Internet-Draft RESTCONF Pagination Support March 2024
+---------------+---------+-----------------------------------------+
| Name | Methods | Description |
+---------------+---------+-----------------------------------------+
| limit | GET, | Limits the number of entries returned. |
| | HEAD | If not specified, the number of entries |
| | | that may be returned is unbounded. |
| | | |
| offset | GET, | Indicates the number of entries in the |
| | HEAD | result set that should the skipped over |
| | | when preparing the response. If not |
| | | specified, then no entries in the |
| | | result set are skipped. |
| | | |
| cursor | GET, | Indicates where to start the working |
| | HEAD | result set, the previous entries are |
| | | skipped over. If not specified, then |
| | | no entries in the result set are |
| | | skipped over. |
| | | |
| direction | GET, | Indicates the direction that the result |
| | HEAD | set is to be traversed. If not |
| | | specified, then the result set is |
| | | traversed in the "forwards" direction. |
| | | |
| sort-by | GET, | Indicates the node name that the result |
| | HEAD | set should be sorted by. If not |
| | | specified, then the result set's |
| | | default order is used, per YANG's |
| | | "ordered-by" statement. |
| | | |
| locale | GET, | Specifies the locale the server should |
| | HEAD | use when collating the result set. If |
| | | not specified, the server chooses what |
| | | locale is used for collation. |
| | | |
| where | GET, | Specifies a filter expression that |
| | HEAD | result set entries must match. If |
| | | not specified, then no entries are |
| | | filtered from the result set. |
| | | |
| sublist-limit | GET, | Limits the number of entries returned |
| | HEAD | returned for descendent lists and |
| | | leaf-lists. If not specified, the |
| | | number of entries that may be returned |
| | | is unbounded. |
+---------------+---------+-----------------------------------------+
Watsen, et al. Expires 2 September 2024 [Page 5]
Internet-Draft RESTCONF Pagination Support March 2024
For all of the query parameters, the query parameter is only allowed
for the GET and HEAD methods on "list" and "leaf-list" data
resources. A "400 Bad Request" status-line MUST be returned if used
with any other method or resource type. The error-tag value
"operation-not-supported" is used in this case.
Per the conformance defined in Section 3.1 of
[I-D.ietf-netconf-list-pagination], all of these parameters MUST be
supported for all lists and leaf-lists, but servers MAY disable the
support for some or all "config false" lists, as described in
Section 3.3 of [I-D.ietf-netconf-list-pagination].
2.3.1. The "limit" Query Parameter
The "limit" query parameter corresponds to the "limit" parameter
defined in Section 3.1.7 of [I-D.ietf-netconf-list-pagination].
If the limit value is invalid, then a "400 Bad Request" status-line
MUST be returned with the error-type value "application" and error-
tag value "invalid-value".
2.3.2. The "offset" Query Parameter
The "offset" query parameter corresponds to the "offset" parameter
defined in Section 3.1.5 of [I-D.ietf-netconf-list-pagination].
If the offset value is invalid, a "400 Bad Request" status-line MUST
be returned with the error-type value "application" and error-tag
value "invalid-value".
If the offset value exceeds the number of entries in the working
result set, then a "416 Range Not Satisfiable" status-line MUST be
returned with the error-type value "application", error-tag value
"invalid-value", and SHOULD also include the "offset-out-of-range"
identity as error-app-tag value.
2.3.3. The "cursor" Query Parameter
The "cursor" querey parameter corresponds to the "cursor" parameter
defined in Section 3.1.6 of [I-D.ietf-netconf-list-pagination].
If the cursor value is unknown, i.e. the key does not exist, a "404
Not Found" status-line MUST be returned with the error-type value
"application" and error-tag value "invalid-value", and SHOULD also
include the "cursor-not-found" identity as error-app-tag value.
Watsen, et al. Expires 2 September 2024 [Page 6]
Internet-Draft RESTCONF Pagination Support March 2024
If the "cursor" query parameter is not supported on the target node,
then a a "501 Not Implemented" status-line MUST be returned with
error-type value "application" and error-tag value "operation-not-
supported".
2.3.4. The "direction" Query Parameter
The "direction" query parameter corresponds to the "direction"
parameter defined in Section 3.1.4 of
[I-D.ietf-netconf-list-pagination].
If the direction value is invalid, then a "400 Bad Request" status-
line MUST be returned with the error-type value "application" and
error-tag value "invalid-value".
2.3.5. The "sort-by" Query Parameter
The "sort-by" query parameter corresponds to the "sort-by" parameter
defined in Section 3.1.2 of [I-D.ietf-netconf-list-pagination].
If the specified node identifier is invalid, then a "400 Bad Request"
status-line MUST be returned with the error-type value "application"
and error-tag value "invalid-value".
2.3.6. The "locale" Query Parameter
The "locale" query parameter corresponds to the "locale" parameter
defined in Section 3.1.3 of [I-D.ietf-netconf-list-pagination].
If the specified node identifier is invalid, i.e. the locale is
unknown to the server, then a "501 Not Implemented" status-line MUST
be returned with the error-type value "application" and error-tag
value "invalid-value", and SHOULD also include the "locale-
unavailable" identity in as the error-app-tag value.
2.3.7. The "where" Query Parameter
The "where" query parameter corresponds to the "where" parameter
defined in Section 3.1.1 of [I-D.ietf-netconf-list-pagination].
If the specified XPath expression is invalid, then a "400 Bad
Request" status-line MUST be returned with the error-type value
"application" and error-tag value "invalid-value".
Watsen, et al. Expires 2 September 2024 [Page 7]
Internet-Draft RESTCONF Pagination Support March 2024
2.3.8. The "sublist-limit" Query Parameter
The "sublist-limit" query parameter corresponds to the "sublist-
limit" parameter defined in Section 3.2.1 of
[I-D.ietf-netconf-list-pagination].
If the sumlist-limit value is invalid, then a "400 Bad Request"
status-line MUST be returned with the error-type value "application"
and error-tag value "invalid-value".
3. IANA Considerations
3.1. The "RESTCONF Capability URNs" Registry
This document registers six capabilities in the RESTCONF Capability
URNs [RFC8040] maintained at https://www.iana.org/assignments/
restconf-capability-urns/restconf-capability-urns.xhtml. Following
the instructions defined in Section 11.4 of [RFC8040], the below
registrations are requested:
All the registrations are to use this document (RFC XXXX) for the
"Reference" value.
Index Capability Identifier
--------------------------------------------------------------------
:limit urn:ietf:params:restconf:capability:limit:1.0
:offset urn:ietf:params:restconf:capability:offset:1.0
:cursor urn:ietf:params:restconf:capability:cursor:1.0
:direction urn:ietf:params:restconf:capability:direction:1.0
:sort-by urn:ietf:params:restconf:capability:sort-by:1.0
:locale urn:ietf:params:restconf:capability:locale:1.0
:where urn:ietf:params:restconf:capability:where:1.0
:sublist-limit urn:ietf:params:restconf:capability:sublist-limit:1.0
3.2. The "Media Types" Registry
This document registers one media type in the "application"
subregistry of the Media Types registry [RFC6838] [RFC4855]
maintained at https://www.iana.org/assignments/media-types/media-
types.xhtml#application. Following the format defined in [RFC4855],
the below registration is requested:
3.2.1. Media Type "application/yang-data+xml-list"
Watsen, et al. Expires 2 September 2024 [Page 8]
Internet-Draft RESTCONF Pagination Support March 2024
Type name: application
Subtype name: yang-data+xml-list
Required parameters: None
Optional parameters: None
Encoding considerations: 8-bit
Each conceptual YANG data node is encoded according to the
XML Encoding Rules and Canonical Format for the specific
YANG data node type defined in [RFC7950].
Security considerations: Security considerations related
to the generation and consumption of RESTCONF messages
are discussed in Section 12 of RFC 8040. Additional
security considerations are specific to the semantics
of particular YANG data models. Each YANG module is
expected to specify security considerations for the
YANG data defined in that module.
Interoperability considerations: RFC XXXX specifies the
format of conforming messages and the interpretation
thereof.
Published specification: RFC XXXX
Applications that use this media type: Instance document data
parsers used within a protocol or automation tool that
utilize the YANG Patch data structure.
Fragment identifier considerations: Fragment identifiers for
this type are not defined. All YANG data nodes are
accessible as resources using the path in the request URI.
Additional information:
Deprecated alias names for this type: N/A
Magic number(s): N/A
File extension(s): None
Macintosh file type code(s): "TEXT"
Person & email address to contact for further information:
See the Authors' Addresses section of RFC XXXX.
Intended usage: COMMON
Restrictions on usage: N/A
Watsen, et al. Expires 2 September 2024 [Page 9]
Internet-Draft RESTCONF Pagination Support March 2024
Author: See the Authors' Addresses section of RFC XXXX.
Change controller: Internet Engineering Task Force
(mailto:iesg@ietf.org).
Provisional registration? (standards tree only): no
4. Security Considerations
This document introduces protocol operations for paging through data
already provided by the RESTCONF protocol, and hence does not
introduce any new security considerations.
This document does not define a YANG module and hence there are no
data modeling considerations beyond those discussed in
[I-D.ietf-netconf-list-pagination].
5. References
5.1. Normative References
[I-D.ietf-netconf-list-pagination]
Watsen, K., Wu, Q., Andersson, P., Hagsand, O., and H. Li,
"List Pagination for YANG-driven Protocols", Work in
Progress, Internet-Draft, draft-ietf-netconf-list-
pagination-03, 1 March 2024,
<https://datatracker.ietf.org/api/v1/doc/document/draft-
ietf-netconf-list-pagination/>.
[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>.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/info/rfc8040>.
[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>.
5.2. Informative References
Watsen, et al. Expires 2 September 2024 [Page 10]
Internet-Draft RESTCONF Pagination Support March 2024
[I-D.ietf-netconf-restconf-collection]
Bierman, A., Björklund, M., and K. Watsen, "RESTCONF
Collection Resource", Work in Progress, Internet-Draft,
draft-ietf-netconf-restconf-collection-00, 30 January
2015, <https://datatracker.ietf.org/doc/html/draft-ietf-
netconf-restconf-collection-00>.
[RFC4855] Casner, S., "Media Type Registration of RTP Payload
Formats", RFC 4855, DOI 10.17487/RFC4855, February 2007,
<https://www.rfc-editor.org/info/rfc4855>.
[RFC6838] Freed, N., Klensin, J., and T. Hansen, "Media Type
Specifications and Registration Procedures", BCP 13,
RFC 6838, DOI 10.17487/RFC6838, January 2013,
<https://www.rfc-editor.org/info/rfc6838>.
[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>.
Appendix A. Example YANG Module
The examples within this document use the "example-social" YANG
module defined in Appendix A.1 of [I-D.ietf-netconf-list-pagination].
Appendix B. Example Data Set
The Example Data Set used by the examples is defined in Appendix A.2
of [I-D.ietf-netconf-list-pagination].
Appendix C. Example Queries
C.1. List pagination with all query parameters
This example mimics that Appendix A.3.9 of
[I-D.ietf-netconf-list-pagination].
=============== NOTE: '\' line wrapping per RFC 8792 ================
GET /restconf/ds/ietf-datastores:running/example-social:members/memb\
er?where=//stats//joined[starts-with(@timestamp,'2020')]&sort-by=tim\
estamp&direction=backwards&offset=2&limit=2&sublist-limit=1 HTTP/1.1
Host: example.com
Accept: application/yang-data+xml-list
Response from the RESTCONF server:
Watsen, et al. Expires 2 September 2024 [Page 11]
Internet-Draft RESTCONF Pagination Support March 2024
=============== NOTE: '\' line wrapping per RFC 8792 ================
HTTP/1.1 200 OK
Date: Thu, 26 Jan 2017 20:56:30 GMT
Server: example-server
Last-Modified: Thu, 26 Jan 2017 20:55:30 GMT
Content-Type: application/yang-data+xml-list
<lp:xml-list xmlns:lp="urn:ietf:params:xml:ns:yang:ietf-restconf-lis\
t-pagination"
xmlns="https://example.com/ns/example-social">
<member lp:remaining="1">
<member-id>eric</member-id>
<email-address>eric@example.com</email-address>
<password>$0$1543</password>
<avatar>BASE64VALUE=</avatar>
<tagline>Go to bed with dreams; wake up with a purpose.</tagline>
<following>alice</following>
<posts>
<post>
<timestamp>2020-09-17T18:02:04Z</timestamp>
<title>Son, brother, husband, father</title>
<body>What's your story?</body>
</post>
</posts>
<favorites>
<bits lp:remaining="2">two</bits>
</favorites>
<stats>
<joined>2020-09-17T19:38:32Z</joined>
<membership-level>pro</membership-level>
<last-activity>2020-09-17T18:02:04Z</last-activity>
</stats>
</member>
<member lp:remaining="1">
<member-id>bob</member-id>
<email-address>bob@example.com</email-address>
<password>$0$1543</password>
<avatar>BASE64VALUE=</avatar>
<tagline>Here and now, like never before.</tagline>
<posts>
<post lp:remaining="2">
<timestamp>2020-08-14T03:32:25Z</timestamp>
<body>Just got in.</body>
</post>
</posts>
<favorites>
<decimal64-numbers lp:remaining="1">3.14159</bits>
Watsen, et al. Expires 2 September 2024 [Page 12]
Internet-Draft RESTCONF Pagination Support March 2024
</favorites>
<stats>
<joined>2020-08-14T03:30:00Z</joined>
<membership-level>standard</membership-level>
<last-activity>2020-08-14T03:34:30Z</last-activity>
</stats>
</member>
</lp:xml-list>
C.2. Deletion of a leaf-list
This example illustrates using a "leaf-list" as the DELETE target.
=============== NOTE: '\' line wrapping per RFC 8792 ================
DELETE /restconf/ds/ietf-datastores:running/example-social:members/m\
ember=bob/favorites/decimal64-numbers HTTP/1.1
Host: example.com
Accept: application/yang-data+xml
Response from the RESTCONF server:
HTTP/1.1 204 No Content
Date: Thu, 26 Jan 2017 20:56:30 GMT
Server: example-server
Acknowledgements
This work has benefited from the discussions of restconf resource
collection over the years, in particular,
[I-D.ietf-netconf-restconf-collection]. The authors additionally
thank the following for lively discussions on list (ordered by first
name): Andy Bierman, Martin Björklund, and Robert Varga
Authors' Addresses
Kent Watsen
Watsen Networks
Email: kent+ietf@watsen.net
Qin Wu
Huawei Technologies
Email: bill.wu@huawei.com
Olof Hagsand
SUNET
Watsen, et al. Expires 2 September 2024 [Page 13]
Internet-Draft RESTCONF Pagination Support March 2024
Email: olof@hagsand.se
Hongwei Li
Hewlett Packard Enterprise
Email: flycoolman@gmail.com
Per Andersson
Cisco Systems
Email: perander@cisco.com
Watsen, et al. Expires 2 September 2024 [Page 14]
