| Internet-Draft | NETCONF Pagination Support | October 2021 |
| Watsen, et al. | Expires 28 April 2022 | [Page] |
This document defines a mapping of the list pagination mechanism defined in [I-D.wwlh-netconf-list-pagination] to NETCONF [RFC6241].¶
This document updates [RFC6241], to augment the <get> and <get-config> "rpc" statements, and [RFC8526], to augment the <get-data> "rpc" statement, to define input parameters necessary for list pagination.¶
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/.¶
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This Internet-Draft will expire on 28 April 2022.¶
Copyright (c) 2021 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 Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.¶
This document defines a mapping of the list pagination mechanism defined in [I-D.wwlh-netconf-list-pagination] to NETCONF [RFC6241].¶
This document updates [RFC6241] and [RFC8526], as described in Section 2.¶
While the pagination mechanism defined in this document is designed for the NETCONF protocol [RFC6241], the augmented RPCs MAY be used by the RESTCONF protocol [RFC8040] if the RESTCONF server implements the "ietf-list-pagination-nc" module.¶
The YANG data model in this document conforms to the Network Management Datastore Architecture defined in [RFC8342]¶
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.¶
Various examples used in this document use a placeholder value for binary data that has been base64 encoded (e.g., "BASE64VALUE="). This placeholder value is used as real base64 encoded structures are often many lines long and hence distracting to the example being presented.¶
The <get> and <get-config> rpc statements are augmented to accept additional input parameters, as described in Section 3.¶
The <get-data> rpc statement is augmented to accept additional input parameters, as described in in Section 3.¶
In order for NETCONF to support [I-D.wwlh-netconf-list-pagination], this document extends the operations <get>, <get-config> and <get-data> to include additional input parameters and output annotations.¶
The updated operations accept a content filter parameter, similar to the "filter" parameter of <get-config>, but includes nodes for "list" and "leaf-list" filtering.¶
The content filter parameter is used to specify the YANG list or leaf-list that is to be retrieved. This must be a path expression used to represent a list or leaf-list data node.¶
The following tree diagram [RFC8340] illustrates the "ietf-netconf-list-pagination" module:¶
module: ietf-list-pagination-nc
augment /nc:get/nc:input:
+---w list-pagination
+---w where? union
+---w sort-by? union
+---w direction? enumeration
+---w offset? uint32
+---w limit? union
+---w sublist-limit? union
augment /nc:get-config/nc:input:
+---w list-pagination
+---w where? union
+---w sort-by? union
+---w direction? enumeration
+---w offset? uint32
+---w limit? union
+---w sublist-limit? union
augment /ncds:get-data/ncds:input:
+---w list-pagination
+---w where? union
+---w sort-by? union
+---w direction? enumeration
+---w offset? uint32
+---w limit? union
+---w sublist-limit? union
¶
Comments:¶
When an input query parameter is supplied with an erroneous value, an <rpc-error> MUST be returned containing the error-type value "application", the error-tag value "invalid-value", and MAY include the error-severity value "error". Additionally the error-app-tag SHOULD be set containing query parameter specific error value.¶
If the "offset" query parameter value supplied is larger then the number of instances in the list or leaf-list target resource, the <rpc-error> MUST contain error-app-tag with value "offset-out-of-range".¶
The "ietf-netconf-list-pagination-nc" module defines conceptual definitions within groupings, which are not meant to be implemented as datastore contents by a server.¶
This module has normative references to [RFC6241], [RFC6243], [RFC6991], and [RFC8342].¶
<CODE BEGINS> file "ietf-list-pagination-nc@2021-10-25.yang"¶
module ietf-list-pagination-nc {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-list-pagination-nc";
prefix lpgnc;
import ietf-netconf {
prefix nc;
reference
"RFC 6241: Network Configuration Protocol (NETCONF)";
}
import ietf-netconf-nmda {
prefix ncds;
reference
"RFC 8526: NETCONF Extensions to Support the
Network Management Datastore Architecture";
}
import ietf-list-pagination {
prefix lp;
reference
"RFC XXXX: List Pagination for YANG-driven Protocols";
}
organization
"IETF NETCONF (Network Configuration) Working Group";
contact
"WG Web: <http://tools.ietf.org/wg/netconf/>
WG List: <mailto:netconf@ietf.org>";
description
"This module augments the <get>, <get-config>, and <get-data>
'rpc' statements to support list pagination.
Copyright (c) 2021 IETF Trust and the persons identified
as authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with
or without modification, is permitted pursuant to, and
subject to the license terms contained in, the Simplified
BSD License set forth in Section 4.c of the IETF Trust's
Legal Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX
(https://www.rfc-editor.org/info/rfcXXXX); see the RFC
itself for full legal notices.
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 (RFC 2119)
(RFC 8174) when, and only when, they appear in all
capitals, as shown here.";
revision 2021-10-25 {
description
"Initial revision.";
reference
"RFC XXXX: NETCONF Extensions to Support List Pagination";
}
grouping pagination-parameters {
description "A grouping for list pagination parameters.";
container list-pagination {
description "List pagination parameters.";
uses lp:where-param-grouping;
uses lp:sort-by-param-grouping;
uses lp:direction-param-grouping;
uses lp:offset-param-grouping;
uses lp:limit-param-grouping;
uses lp:sublist-limit-param-grouping;
}
}
augment "/nc:get/nc:input" {
description
"Allow the 'get' operation to use content filter
parameter for specifying the YANG list or leaf-list
that is to be retrieved";
uses pagination-parameters;
}
augment "/nc:get-config/nc:input" {
description
"Allow the 'get-config' operation to use content filter
parameter for specifying the YANG list or leaf-list
that is to be retrieved";
uses pagination-parameters;
}
augment "/ncds:get-data/ncds:input" {
description
"Allow the 'get-data' operation to use content filter
parameter for specifying the YANG list or leaf-list
that is to be retrieved";
uses pagination-parameters;
}
}
¶
<CODE ENDS>¶
This document registers one URI in the "ns" subregistry of the IETF XML Registry [RFC3688] maintained at https://www.iana.org/assignments/xml-registry/xml-registry.xhtml#ns. Following the format in [RFC3688], the following registration is requested:¶
URI: urn:ietf:params:xml:ns:yang:ietf-list-pagination-nc Registrant Contact: The IESG. XML: N/A, the requested URI is an XML namespace.¶
This document registers one YANG module in the YANG Module Names registry [RFC6020] maintained at https://www.iana.org/assignments/yang-parameters/yang-parameters.xhtml. Following the format defined in [RFC6020], the below registration is requested:¶
name: ietf-list-pagination-nc namespace: urn:ietf:params:xml:ns:yang:ietf-list-pagination-nc prefix: pgnc RFC: XXXX¶
The YANG module defined in this document extends the base operations for NETCONF [RFC6241] and RESTCONF [RFC8040]. The lowest NETCONF layer is the secure transport layer, and the mandatory-to-implement secure transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement secure transport is TLS [RFC8446].¶
The Network Configuration Access Control Model (NACM) [RFC8341] provides the means to restrict access for particular NETCONF users to a preconfigured subset of all available NETCONF protocol operations and content.¶
The security considerations for the base NETCONF protocol operations (see Section 9 of [RFC6241] apply to the new <get-list-pagination> RPC operations defined in this document.¶
Cursors (i.e.,stable result sets) are related to the topic of dynamic changing lists between two queries. How cursors can be supported using "feature"?¶
The examples within this document use the "example-social" YANG module defined in Appendix A.1 of [I-D.wwlh-netconf-list-pagination].¶
The Example Data Set used by the examples is defined in Appendix A.2 of [I-D.wwlh-netconf-list-pagination].¶
This example mimics that Appendix A.3.7 of [I-D.wwlh-netconf-list-pagination].¶
=============== NOTE: '\' line wrapping per RFC 8792 ================
<rpc xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" message-id="42">
<get-config>
<source>
<running/>
</source>
<filter type="xpath" select="/es:members/es:member"
xmlns:es="http://example.com/ns/example-social"/>
<list-pagination
xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-list-paginat\
ion">true</list-pagination>
<where>//stats//joined[starts-with(@timestamp,'2020')]</where>
<sort-by>timestamp</sort-by>
<direction>backwards</direction>
<offset>2</offset>
<limit>2</limit>
<sublist-limit>1</sublist-limit>
</filter>
</get-config>
</rpc>
¶
Response from the NETCONF server:¶
=============== NOTE: '\' line wrapping per RFC 8792 ================
<lp:xml-list xmlns:lp="urn:ietf:params:xml:ns:yang:ietf-restconf-lis\
t-pagination"
xmlns="http://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>
</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>
¶
This work has benefited from the discussions of RESTCONF resource collection over the years, in particular, [I-D.ietf-netconf-restconf-collection] which provides enhanced filtering features for the retrieval of data nodes with the GET method and [I-D.zheng-netconf-fragmentation] which document large size data handling challenge. The authors would like to thank the following for lively discussions on list:¶
Andy Bierman Martin Björklund Robert Varga¶