Internet DRAFT - draft-bierman-netconf-restconf
draft-bierman-netconf-restconf
Network Working Group A. Bierman
Internet-Draft YumaWorks
Intended status: Standards Track M. Bjorklund
Expires: August 17, 2014 Tail-f Systems
K. Watsen
Juniper Networks
R. Fernando
Cisco
February 13, 2014
RESTCONF Protocol
draft-bierman-netconf-restconf-04
Abstract
This document describes a REST-like protocol that provides a
programmatic interface over HTTP for accessing data defined in YANG,
using the datastores defined in NETCONF.
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
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on August 17, 2014.
Copyright Notice
Copyright (c) 2014 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
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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.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1. Simple Subset of NETCONF Functionality . . . . . . . . . . 5
1.2. Data Model Driven API . . . . . . . . . . . . . . . . . . 6
1.3. Terminology . . . . . . . . . . . . . . . . . . . . . . . 8
1.3.1. NETCONF . . . . . . . . . . . . . . . . . . . . . . . 8
1.3.2. HTTP . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.3.3. YANG . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.3.4. Terms . . . . . . . . . . . . . . . . . . . . . . . . 9
1.3.5. Tree Diagrams . . . . . . . . . . . . . . . . . . . . 11
2. Operations . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.1. OPTIONS . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.2. HEAD . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.3. GET . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.4. POST . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.4.1. Create Resource Mode . . . . . . . . . . . . . . . . . 14
2.4.2. Invoke Operation Mode . . . . . . . . . . . . . . . . 15
2.5. PUT . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2.6. PATCH . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.7. DELETE . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.8. Query Parameters . . . . . . . . . . . . . . . . . . . . . 19
3. Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.1. Request URI Structure . . . . . . . . . . . . . . . . . . 21
3.2. Message Headers . . . . . . . . . . . . . . . . . . . . . 22
3.3. Message Encoding . . . . . . . . . . . . . . . . . . . . . 23
3.4. RESTCONF Meta-Data . . . . . . . . . . . . . . . . . . . . 23
3.4.1. JSON Encoding of RESTCONF Meta-Data . . . . . . . . . 24
3.5. Return Status . . . . . . . . . . . . . . . . . . . . . . 26
3.6. Message Caching . . . . . . . . . . . . . . . . . . . . . 26
4. Resources . . . . . . . . . . . . . . . . . . . . . . . . . . 27
4.1. RESTCONF Resource Types . . . . . . . . . . . . . . . . . 27
4.2. Resource Discovery . . . . . . . . . . . . . . . . . . . . 28
4.3. API Resource (/restconf) . . . . . . . . . . . . . . . . . 28
4.3.1. /restconf/data . . . . . . . . . . . . . . . . . . . . 29
4.3.2. /restconf/modules . . . . . . . . . . . . . . . . . . 30
4.3.3. /restconf/operations . . . . . . . . . . . . . . . . . 31
4.3.4. /restconf/streams . . . . . . . . . . . . . . . . . . 31
4.3.5. /restconf/version . . . . . . . . . . . . . . . . . . 31
4.4. Datastore Resource . . . . . . . . . . . . . . . . . . . . 31
4.4.1. Edit Collision Detection . . . . . . . . . . . . . . . 32
4.5. Data Resource . . . . . . . . . . . . . . . . . . . . . . 33
4.5.1. Encoding YANG Instance Identifiers in the Request
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URI . . . . . . . . . . . . . . . . . . . . . . . . . 33
4.5.2. Defaults Handling . . . . . . . . . . . . . . . . . . 36
4.6. Operation Resource . . . . . . . . . . . . . . . . . . . . 36
4.6.1. Encoding Operation Input Parameters . . . . . . . . . 37
4.6.2. Encoding Operation Output Parameters . . . . . . . . . 38
4.7. Schema Resource . . . . . . . . . . . . . . . . . . . . . 39
4.8. Stream Resource . . . . . . . . . . . . . . . . . . . . . 39
5. Notifications . . . . . . . . . . . . . . . . . . . . . . . . 41
5.1. Server Support . . . . . . . . . . . . . . . . . . . . . . 41
5.2. Event Streams . . . . . . . . . . . . . . . . . . . . . . 41
5.3. Subscribing to Receive Notifications . . . . . . . . . . . 42
5.3.1. NETCONF Event Stream . . . . . . . . . . . . . . . . . 43
5.4. Receiving Event Notifications . . . . . . . . . . . . . . 43
6. Error Reporting . . . . . . . . . . . . . . . . . . . . . . . 45
6.1. Error Response Message . . . . . . . . . . . . . . . . . . 46
7. RESTCONF module . . . . . . . . . . . . . . . . . . . . . . . 49
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 63
8.1. YANG Module Registry . . . . . . . . . . . . . . . . . . . 63
8.2. application/yang Media Sub Types . . . . . . . . . . . . . 63
9. Security Considerations . . . . . . . . . . . . . . . . . . . 65
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 66
10.1. Normative References . . . . . . . . . . . . . . . . . . . 66
10.2. Informative References . . . . . . . . . . . . . . . . . . 67
Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 68
A.1. 03 to 04 . . . . . . . . . . . . . . . . . . . . . . . . . 68
A.2. 02 to 03 . . . . . . . . . . . . . . . . . . . . . . . . . 68
A.3. 01 to 02 . . . . . . . . . . . . . . . . . . . . . . . . . 69
A.4. 00 to 01 . . . . . . . . . . . . . . . . . . . . . . . . . 69
A.5. YANG-API-01 to RESTCONF-00 . . . . . . . . . . . . . . . . 70
Appendix B. Open Issues . . . . . . . . . . . . . . . . . . . . . 72
B.1. message-id . . . . . . . . . . . . . . . . . . . . . . . . 72
B.2. select parameter . . . . . . . . . . . . . . . . . . . . . 72
B.3. server support verification . . . . . . . . . . . . . . . 72
B.4. error media type . . . . . . . . . . . . . . . . . . . . . 72
B.5. additional datastores . . . . . . . . . . . . . . . . . . 72
B.6. PATCH media type discovery . . . . . . . . . . . . . . . . 72
B.7. RESTCONF version . . . . . . . . . . . . . . . . . . . . . 72
B.8. YANG to resource mapping . . . . . . . . . . . . . . . . . 73
B.9. .well-known usage . . . . . . . . . . . . . . . . . . . . 73
B.10. _self links for HATEOAS support . . . . . . . . . . . . . 74
B.11. netconf-state monitoring support . . . . . . . . . . . . . 74
B.12. secure transport . . . . . . . . . . . . . . . . . . . . . 74
Appendix C. Example YANG Module . . . . . . . . . . . . . . . . . 75
C.1. example-jukebox YANG Module . . . . . . . . . . . . . . . 75
Appendix D. RESTCONF Message Examples . . . . . . . . . . . . . . 81
D.1. Resource Retrieval Examples . . . . . . . . . . . . . . . 81
D.1.1. Retrieve the Top-level API Resource . . . . . . . . . 81
D.1.2. Retrieve The Server Module Information . . . . . . . . 83
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D.2. Edit Resource Examples . . . . . . . . . . . . . . . . . . 85
D.2.1. Create New Data Resources . . . . . . . . . . . . . . 85
D.2.2. Detect Resource Entity Tag Change . . . . . . . . . . 86
D.3. Query String Parameter Examples . . . . . . . . . . . . . 86
D.3.1. "content" Parameter . . . . . . . . . . . . . . . . . 86
D.3.2. "depth" Parameter . . . . . . . . . . . . . . . . . . 89
D.3.3. "filter" Parameter . . . . . . . . . . . . . . . . . . 92
D.3.4. "insert" Parameter . . . . . . . . . . . . . . . . . . 93
D.3.5. "point" Parameter . . . . . . . . . . . . . . . . . . 94
D.3.6. "select" Parameter . . . . . . . . . . . . . . . . . . 94
D.3.7. "start-time" Parameter . . . . . . . . . . . . . . . . 95
D.3.8. "stop-time" Parameter . . . . . . . . . . . . . . . . 95
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 96
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1. Introduction
There is a need for standard mechanisms to allow WEB applications to
access the configuration data, operational data, data-model specific
protocol operations, and notification events within a networking
device, in a modular and extensible manner.
This document describes a REST-like protocol called RESTCONF, running
over HTTP [RFC2616], for accessing data defined in YANG [RFC6020],
using datastores defined in NETCONF [RFC6241].
The NETCONF protocol defines configuration datastores and a set of
Create, Retrieve, Update, Delete (CRUD) operations that can be used
to access these datastores. The YANG language defines the syntax and
semantics of datastore content, operational data, protocol
operations, and notification events. REST-like operations are used
to access the hierarchical data within a datastore.
A REST-like API can be created that provides CRUD operations on a
NETCONF datastore containing YANG-defined data. This can be done in
a simplified manner, compatible with HTTP and REST-like design
principles. Since NETCONF protocol operations are not relevant, the
user should not need any prior knowledge of NETCONF in order to use
the REST-like API.
Configuration data and state data are exposed as resources that can
be retrieved with the GET method. Resources representing
configuration data can be modified with the DELETE, PATCH, POST, and
PUT methods. Data is encoded with either XML [W3C.REC-xml-20081126]
or JSON [JSON].
Data-model specific protocol operations defined with the YANG "rpc"
statement can be invoked with the POST method. Data-model specific
notification events defined with the YANG "notification" statement
can be accessed.
1.1. Simple Subset of NETCONF Functionality
The framework and meta-model used for a REST-like API does not need
to mirror those used by the NETCONF protocol, but it needs to be
compatible with NETCONF. A simplified framework and protocol is
needed that utilizes the three NETCONF datastores (candidate,
running, startup), but hides the complexity of multiple datastores
from the client.
A simplified transaction model is needed that allows basic CRUD
operations on a hierarchy of conceptual resources. This represents a
limited subset of the transaction capabilities of the NETCONF
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protocol.
Applications that require more complex transaction capabilities might
consider NETCONF instead of RESTCONF. The following transaction
features are not directly provided in RESTCONF:
o datastore locking (full or partial)
o candidate datastore
o startup datastore
o validate operation
o confirmed-commit procedure
The REST-like API is not intended to replace NETCONF, but rather
provide an additional simplified interface that follows REST-like
principles and is compatible with a resource-oriented device
abstraction.
The following figure shows the system components:
+-----------+ +-----------------+
| WEB app | <-------> | |
+-----------+ HTTP | network device |
| |
+-----------+ | +-----------+ |
| NMS app | <-------> | | datastore | |
+-----------+ NETCONF | +-----------+ |
+-----------------+
1.2. Data Model Driven API
RESTCONF combines the simplicity of a REST-like API over HTTP with
the predictability and automation potential of a schema-driven API.
A REST-like client using HATEOAS principles would not use any data
modeling language to define the application-specific content of the
API. The client would discover each new child resource as it
traverses the URIs returned as Location IDs to discover the server
capabilities.
This approach has 3 significant weaknesses with regards to control of
complex networking devices:
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o inefficient performance: configuration APIs will be quite complex
and may require thousands of protocol messages to discover all the
schema information. Typically the data type information has to be
passed in the protocol messages, which is also wasteful overhead.
o no data model richness: without a data model, the schema-level
semantics and validation constraints are not available to the
application.
o no tool automation: API automation tools need some sort of content
schema to function. Such tools can automate various programming
and documentation tasks related to specific data models.
Data model modules such as YANG modules serve as an "API contract"
that will be honored by the server. An application designer can code
to the data model, knowing in advance important details about the
exact protocol operations and datastore content a conforming server
implementation will support.
RESTCONF provides the YANG module capability information supported by
the server, in case the client wants to use it. The URIs for custom
protocol operations and datastore content are predictable, based on
the YANG module definitions.
Operational experience with CLI and SNMP indicates that operators
learn the 'location' of specific service or device related data and
do not expect such information to be arbitrary and discovered each
time the client opens a management session to a server.
The RESTCONF protocol operates on a conceptual datastore defined with
the YANG data modeling language. The server lists each YANG module
it supports under "/restconf/modules" in the top-level API resource
type, using a structure based on the YANG module capability URI
format defined in [RFC6020].
The conceptual datastore contents, data-model-specific operations and
notification events are identified by this set of YANG module
resources. All RESTCONF content identified as either a data
resource, operation resource, or event stream resource is defined
with the YANG language.
The classification of data as configuration or non-configuration is
derived from the YANG "config" statement. Data ordering behavior is
derived from the YANG "ordered-by" statement.
The RESTCONF datastore editing model is simple and direct, similar to
the behavior of the ":writable-running" capability in NETCONF. Each
RESTCONF edit of a datastore resource is activated upon successful
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completion of the transaction.
1.3. Terminology
The keywords "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].
1.3.1. NETCONF
The following terms are defined in [RFC6241]:
o candidate configuration datastore
o client
o configuration data
o datastore
o configuration datastore
o protocol operation
o running configuration datastore
o server
o startup configuration datastore
o state data
o user
1.3.2. HTTP
The following terms are defined in [RFC2616]:
o entity tag
o fragment
o header line
o message body
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o method
o path
o query
o request URI
o response body
1.3.3. YANG
The following terms are defined in [RFC6020]:
o container
o data node
o key leaf
o leaf
o leaf-list
o list
o presence container (or P-container)
o RPC operation (now called protocol operation)
o non-presence container (or NP-container)
o ordered-by system
o ordered-by user
1.3.4. Terms
The following terms are used within this document:
o API resource: a resource with the media type "application/
yang.api+xml" or "application/yang.api+json". API resources can
only be edited by the server.
o data resource: a resource with the media type "application/
yang.data+xml" or "application/yang.data+json". Data resources
can be edited by clients or the server. All YANG data node types
can be data resources. YANG terminal nodes cannot contain sub-
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resources.
o datastore resource: a resource with the media type "application/
yang.datastore+xml" or "application/yang.datastore+json".
Represents a configuration datastore.
o edit operation: a RESTCONF operation on a data resource using the
POST, PUT, PATCH, or DELETE method.
o event stream resource: a resource with the media type
"application/yang.stream+xml" or "application/yang.stream+json".
This resource represents an SSE (Server-Sent Events) event stream.
The content consists of text using the media type "text/
event-stream", as defined by the HTML5 specification. Each event
represents one <notification> message generated by the server. It
contains a conceptual system or data-model specific event that is
delivered within a notification event stream.
o operation: the conceptual RESTCONF operation for a message,
derived from the HTTP method, request URI, headers, and message
body.
o operation resource: a resource with the media type "application/
yang.operation+xml" or "application/yang.operation+json".
o patch: a generic PATCH method on the target datastore or data
resource. The media type of the message body content will
identify the patch type in use.
o plain patch: a PATCH method where the media type is "application/
yang.data+xml" or "application/yang.data+json".
o query parameter: a parameter (and its value if any), encoded
within the query component of the request URI.
o requested data nodes: the set of data resources identified by the
target resource, or the "select" query parameter if it is present.
o resource: a conceptual object representing a manageable component
within a device. Refers to the resource itself of the resource
and all its sub-resources.
o retrieval request: a request using the GET or HEAD methods.
o target resource: the resource that is associated with a particular
message, identified by the "path" component of the request URI.
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o unified datastore: A conceptual representation of the device
running configuration. The server will hide all NETCONF datastore
details for edit operations, such as the ":candidate" and
":startup" capabilities.
o YANG schema resource: a resource with the media type "application/
yang". The YANG representation of the schema can be retrieved by
the client with the GET method.
o YANG terminal node: a YANG node representing a leaf, leaf-list, or
anyxml definition.
1.3.5. Tree Diagrams
A simplified graphical representation of the data model is used in
this document. The meaning of the symbols in these diagrams is as
follows:
o Brackets "[" and "]" enclose list keys.
o Abbreviations before data node names: "rw" means configuration
(read-write) and "ro" state data (read-only).
o Symbols after data node names: "?" means an optional node and "*"
denotes a "list" and "leaf-list".
o Parentheses enclose choice and case nodes, and case nodes are also
marked with a colon (":").
o Ellipsis ("...") stands for contents of subtrees that are not
shown.
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2. Operations
The RESTCONF protocol uses HTTP methods to identify the CRUD
operation requested for a particular resource. The following table
shows how the RESTCONF operations relate to NETCONF protocol
operations:
+----------+-------------------------------------+
| RESTCONF | NETCONF |
+----------+-------------------------------------+
| OPTIONS | none |
| HEAD | none |
| GET | <get-config>, <get> |
| POST | <edit-config> (operation="create") |
| PUT | <edit-config> (operation="replace") |
| PATCH | <edit-config> (operation="merge") |
| DELETE | <edit-config> (operation="delete") |
+----------+-------------------------------------+
Table 1: CRUD Methods in RESTCONF
The NETCONF "remove" operation attribute is not supported by the HTTP
DELETE method. The resource must exist or the DELETE method will
fail. The PATCH method is equivalent to a "merge" operation for a
plain PATCH method.
Access control mechanims may be used to limit what operations can be
used. In particular, RESTCONF is compatible with the NETCONF Access
Control Model (NACM) [RFC6536], as there is a specific mapping
between RESTCONF and NETCONF operations, defined in Table 1. The
resource path needs to be converted internally by the server to the
corresponding
YANG instance-identifier. Using this information,
the server can apply the NACM access control rules to RESTCONF
messages.
The server MUST NOT allow any operation to any resources that the
client is not authorized to access.
Implementation of all methods (except PATCH) are defined in
[RFC2616]. This section defines the RESTCONF protocol usage for each
HTTP method.
2.1. OPTIONS
The OPTIONS method is sent by the client to discover which methods
are supported by the server for a specific resource. If supported,
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it SHOULD be implemented for all media types. The server SHOULD
implement this method, however the same information could be
extracted from the YANG modules and the RESTCONF protocol
specification.
2.2. HEAD
The HEAD method is sent by the client to retrieve just the headers
that would be returned for the comparable GET method, without the
response body. It is supported for all resource types, except
operation resources.
The request MUST contain a request URI that contains at least the
entry point component. The same query parameters supported by the
GET method are supported by the HEAD method.
The access control behavior is enforced as if the method was GET
instead of HEAD. The server MUST respond the same as if the method
was GET instead of HEAD, except that no response body is included.
2.3. GET
The GET method is sent by the client to retrieve data and meta-data
for a resource. It is supported for all resource types, except
operation resources. The request MUST contain a request URI that
contains at least the entry point component.
The server MUST NOT return any data resources for which the user does
not have read privileges. If the user is not authorized to read any
portion of the target resource, an error response containing a "403
Forbidden" Status-Line is returned to the client.
If the user is authorized to read some but not all of the target
resource, the unauthorized content is omitted from the response
message body, and the authorized content is returned to the client.
Example:
The client might request the response headers for a JSON
representation of the "library" resource:
GET /restconf/data/example-jukebox:jukebox/
library/artist/Foo%20Fighters/album HTTP/1.1
Host: example.com
Accept: application/yang.data+json
The server might respond:
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HTTP/1.1 200 OK
Date: Mon, 23 Apr 2012 17:02:40 GMT
Server: example-server
Content-Type: application/yang.data+json
Cache-Control: no-cache
Pragma: no-cache
ETag: a74eefc993a2b
Last-Modified: Mon, 23 Apr 2012 11:02:14 GMT
{
"album" : {
"name" : "Wasting Light",
"genre" : "example-jukebox:alternative",
"year" : 2011
}
}
Refer to @ex-create@ for more resource creation examples.
2.4. POST
The POST method is sent by the client to create a data resource or
invoke an operation resource. The server uses the target resource
media type to determine how to process the request.
+-----------+------------------------------------------------+
| Type | Description |
+-----------+------------------------------------------------+
| Datastore | Create a top-level configuration data resource |
| Data | Create a configuration data sub-resource |
| Operation | Invoke a protocol operation |
+-----------+------------------------------------------------+
Resource Types that Support POST
The request MUST contain a request URI that contains a target
resource which identifies a datastore, data, or operation resource
type.
2.4.1. Create Resource Mode
If the target resource type is a datastore or data resource, then the
POST is treated as a request to create a resource or sub-resource.
The message body is expected to contain the content of a child
resource to create within the parent (target resource).
The "insert" and "point" query parameters are supported by the POST
method for datastore and data resource types, as specified in the
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YANG definition in Section 7.
If the POST method succeeds, a "201 Created" Status-Line is returned
and there is no response message body. A "Location" header
identifying the child resource that was created MUST be present in
the response in this case.
If the user is not authorized to create the target resource, an error
response containing a "403 Forbidden" Status-Line is returned to the
client. All other error responses are handled according to the
procedures defined in Section 6.
Example:
To create a new "jukebox" resource, the client might send:
POST /restconf/data HTTP/1.1
Host: example.com
Content-Type: application/yang.data+json
{ "example-jukebox:jukebox" : [null] }
If the resource is created, the server might respond as follows:
HTTP/1.1 201 Created
Date: Mon, 23 Apr 2012 17:01:00 GMT
Server: example-server
Location: http://example.com/restconf/data/example-jukebox:jukebox
Last-Modified: Mon, 23 Apr 2012 17:01:00 GMT
ETag: b3a3e673be2
2.4.2. Invoke Operation Mode
If the target resource type is an operation resource, then the POST
method is treated as a request to invoke that operation. The message
body (if any) is processed as the operation input parameters. Refer
to Section 4.6 for details on operation resources.
If the POST method succeeds, a "200 OK" Status-Line is returned if
there is a response message body, and a "204 No Content" Status-Line
is returned if there is no response message body.
If the user is not authorized to invoke the target operation, an
error response containing a "403 Forbidden" Status-Line is returned
to the client. All other error responses are handled according to
the procedures defined in Section 6.
Example:
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In this example, the client is invoking the "play" operation defined
in the "example-jukebox" YANG module.
A client might send a "play" request as follows:
POST /restconf/operations/example-jukebox:play HTTP/1.1
Host: example.com
Content-Type: application/yang.operation+json
{
"example-jukebox:input" : {
"playlist" : "Foo-One",
"song-number" : 2
}
}
The server might respond:
HTTP/1.1 204 No Content
Date: Mon, 23 Apr 2012 17:50:00 GMT
Server: example-server
2.5. PUT
The PUT method is sent by the client to create or replace the target
resource.
The request MUST contain a request URI that contains a target
resource that identifies the data resource to create or replace.
If the resource instance does not exist, and it represents a valid
instance the server could create with a POST request, then the server
SHOULD create it.
The message body is expected to contain the content used to create or
replace the target resource.
The "insert" and "point" query parameters are supported by the PUT
method for data resources, as specified in the YANG definition in
Section 7.
Consistent with [RFC2616], if the PUT method creates a new resource,
a "201 Created" Status-Line is returned. If an existing resource is
modified, either "200 OK" or "204 No Content" are returned.
If the user is not authorized to create or replace the target
resource an error response containing a "403 Forbidden" Status-Line
is returned to the client. All other error responses are handled
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according to the procedures defined in Section 6.
Example:
An "album" sub-resource defined in the "example-jukebox" YANG module
is replaced or created if it does not already exist.
To replace the "album" resource contents, the client might send as
follows. Note that the request URI header line is wrapped for
display purposes only:
PUT /restconf/data/example-jukebox:jukebox/
library/artist/Foo%20Fighters/album/Wasting%20Light HTTP/1.1
Host: example.com
Content-Type: application/yang.data+json
{
"example-jukebox:album" : {
"name" : "Wasting Light",
"genre" : "example-jukebox:alternative",
"year" : 2011
}
}
If the resource is updated, the server might respond:
HTTP/1.1 204 No Content
Date: Mon, 23 Apr 2012 17:04:00 GMT
Server: example-server
Last-Modified: Mon, 23 Apr 2012 17:04:00 GMT
ETag: b27480aeda4c
2.6. PATCH
The PATCH method uses the HTTP PATCH method defined in [RFC5789] to
provide an extensible framework for resource patching mechanisms. It
is optional to implement by the server. Each patch type needs a
unique media type. Zero or more PATCH media types MAY be supported
by the server.
The "plain patch" PATCH method is used to create or update a sub-
resource within the target resource. If the target resource instance
does not exist, the server MUST NOT create it.
If the PATCH method succeeds, a "200 OK" Status-Line is returned if
there is a message body, and "204 No Content" is returned if no
response message body is sent.
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If the user is not authorized to alter the target resource an error
response containing a "403 Forbidden" Status-Line is returned to the
client. All other error responses are handled according to the
procedures defined in Section 6.
Example:
To replace just the "year" field in the "album" resource (instead of
replacing the entire resource with the PUT method), the client might
send a plain patch as follows. Note that the request URI header line
is wrapped for display purposes only:
PATCH /restconf/data/example-jukebox:jukebox/
library/artist/Foo%20Fighters/album/Wasting%20Light HTTP/1.1
Host: example.com
Content-Type: application/yang.data+json
{
"example-jukebox:album" : {
"genre" : "example-jukebox:rock",
"year" : 2011
}
}
If the field is updated, the server might respond:
HTTP/1.1 204 No Content
Date: Mon, 23 Apr 2012 17:49:30 GMT
Server: example-server
Last-Modified: Mon, 23 Apr 2012 17:49:30 GMT
ETag: b2788923da4c
The XML encoding for the same request might be:
PATCH /restconf/data/example-jukebox:jukebox/
library/artist/Foo%20Fighters/album/Wasting%20Light HTTP/1.1
Host: example.com
If-Match: b8389233a4c
Content-Type: application/yang.data+xml
<album xmlns="http://example.com/ns/example-jukebox">
<genre>example-jukebox:rock</genre>
<year>2011</year>
</album>
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2.7. DELETE
The DELETE method is used to delete the target resource. If the
DELETE method succeeds, a "204 No Content" Status-Line is returned,
and there is no response message body.
If the user is not authorized to delete the target resource then an
error response containing a "403 Forbidden" Status-Line is returned
to the client. All other error responses are handled according to
the procedures defined in Section 6.
Example:
To delete a resource such as the "album" resource, the client might
send:
DELETE /restconf/data/example-jukebox:jukebox/
library/artist/Foo%20Fighters/album/Wasting%20Light HTTP/1.1
Host: example.com
If the resource is deleted, the server might respond:
HTTP/1.1 204 No Content
Date: Mon, 23 Apr 2012 17:49:40 GMT
Server: example-server
2.8. Query Parameters
Each RESTCONF operation allows zero or more query parameters to be
present in the request URI. The specific parameters that are allowed
depends on the resource type, and sometimes the specific target
resource used, in the request.
+------------+----------+-------------------------------------------+
| Name | Methods | Description |
+------------+----------+-------------------------------------------+
| content | GET | Select config and/or non-config data |
| | | resources |
| depth | GET | Request limited sub-tree depth in the |
| | | reply content |
| filter | GET | Boolean notification filter for |
| | | event-stream resources |
| insert | POST, | Insertion mode for user-ordered data |
| | PUT | resources |
| point | POST, | Insertion point for user-ordered data |
| | PUT | resources |
| select | GET | Request a subset of the target resource |
| | | contents |
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| start-time | GET | Replay buffer start time for event-stream |
| | | resources |
| stop-time | GET | Replay buffer stop time for event-stream |
| | | resources |
+------------+----------+-------------------------------------------+
RESTCONF Query Parameters
Query parameters can be given in any order. Each parameter can
appear at most once in a request URI. A default value may apply if
the parameter is missing.
The semantics and syntax for all query parameters are defined in the
"query-parameters" YANG grouping in Section 7. The YANG encoding
MUST be converted to URL-encoded string for use in the request URI.
Refer to Appendix D.3 for examples of query parameter usage.
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3. Messages
The RESTCONF protocol uses HTTP entities for messages. A single HTTP
message corresponds to a single protocol method. Most messages can
perform a single task on a single resource, such as retrieving a
resource or editing a resource. The exception is the PATCH method,
which allows multiple datastore edits within a single message.
3.1. Request URI Structure
Resources are represented with URIs following the structure for
generic URIs in [RFC3986].
A RESTCONF operation is derived from the HTTP method and the request
URI, using the following conceptual fields:
<OP> /restconf/<path>?<query>#<fragment>
^ ^ ^ ^ ^
| | | | |
method entry resource query fragment
M M O O I
M=mandatory, O=optional, I=ignored
<text> replaced by client with real values
o method: the HTTP method identifying the RESTCONF operation
requested by the client, to act upon the target resource specified
in the request URI. RESTCONF operation details are described in
Section 2.
o entry: the well-known RESTCONF entry point ("/restconf").
o resource: the path expression identifying the resource that is
being accessed by the operation. If this field is not present,
then the target resource is the API itself, represented by the
media type "application/yang.api".
o query: the set of parameters associated with the RESTCONF message.
These have the familiar form of "name=value" pairs. There is a
specific set of parameters defined, although the server MAY choose
to support additional parameters not defined in this document.
The contents of the any query parameter value MUST be encoded
according to [RFC2396], section 3.4. Any reserved characters MUST
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be encoded with escape sequences, according to [RFC2396], section
2.4.
o fragment: This field is not used by the RESTCONF protocol.
When new resources are created by the client, a "Location" header is
returned, which identifies the path of the newly created resource.
The client MUST use this exact path identifier to access the resource
once it has been created.
The "target" of an operation is a resource. The "path" field in the
request URI represents the target resource for the operation.
3.2. Message Headers
There are several HTTP header lines utilized in RESTCONF messages.
Messages are not limited to the HTTP headers listed in this section.
HTTP defines which header lines are required for particular
circumstances. Refer to each operation definition section in
Section 2 for examples on how particular headers are used.
There are some request headers that are used within RESTCONF, usually
applied to data resources. The following tables summarize the
headers most relevant in RESTCONF message requests:
+---------------------+---------------------------------------------+
| Name | Description |
+---------------------+---------------------------------------------+
| Accept | Response Content-Types that are acceptable |
| Content-Type | The media type of the request body |
| Host | The host address of the server |
| If-Match | Only perform the action if the entity |
| | matches ETag |
| If-Modified-Since | Only perform the action if modified since |
| | time |
| If-Unmodified-Since | Only perform the action if un-modified |
| | since time |
+---------------------+---------------------------------------------+
RESTCONF Request Headers
The following tables summarize the headers most relevant in RESTCONF
message responses:
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+---------------+---------------------------------------------------+
| Name | Description |
+---------------+---------------------------------------------------+
| Allow | Valid actions when 405 error returned |
| Cache-Control | The cache control parameters for the response |
| Content-Type | The media type of the response body |
| Date | The date and time the message was sent |
| ETag | An identifier for a specific version of a |
| | resource |
| Last-Modified | The last modified date and time of a resource |
| Location | The resource identifier for a newly created |
| | resource |
+---------------+---------------------------------------------------+
RESTCONF Response Headers
3.3. Message Encoding
RESTCONF messages are encoded in HTTP according to RFC 2616. The
"utf-8" character set is used for all messages. RESTCONF message
content is sent in the HTTP message body.
Content is encoded in either JSON or XML format.
XML encoding rules for data nodes are defined in [RFC6020]. The same
encoding rules are used for all XML content.
JSON encoding rules are defined in [I-D.lhotka-netmod-json]. This
encoding is valid JSON, but also has special encoding rules to
identify module namespaces and provide consistent type processing of
YANG data.
Request input content encoding format is identified with the Content-
Type header. This field MUST be present if a message body is sent by
the client.
Response output content encoding format is identified with the Accept
header in the request, or if is not specified, the request input
encoding format is used. If there was no request input, then the
default output encoding is XML. File extensions encoded in the
request are not used to identify format encoding.
3.4. RESTCONF Meta-Data
The RESTCONF protocol needs to retrieve the same meta-data that is
used in the NETCONF protocol. Information about default leafs, last-
modified timestamps, etc. are commonly used to annotate
representations of the datastore contents. This meta-data is not
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defined in the YANG schema because it applies to the datastore, and
is common across all data nodes.
This information is encoded as attributes in XML, but JSON does not
have a standard way of attaching non-schema defined meta-data to a
resource.
3.4.1. JSON Encoding of RESTCONF Meta-Data
The YANG to JSON mapping [I-D.lhotka-netmod-json] does not support
attributes because YANG does not support meta-data in data node
definitions. This section specifies how RESTCONF meta-data is
encoded in JSON.
Only simple meta-data is supported:
o A meta-data instance can appear 0 or 1 times for a particular data
node
o A meta-data instance associated with a resource is encoded as if
it were a YANG leaf of type "string", according to the encoding
rules in [I-D.lhotka-netmod-json], except the identifier is
prepended with a "@" (%40) character.
o A meta-data instance associated with a YANG leaf or leaf-list
within a resource is encoded as if it were a container for the
meta-data values and the resource value in its native encoding.
It is encoded according to the rules in [I-D.lhotka-netmod-json],
except the meta-data identifiers are prepended with a "@" (%40)
character. The resource name/value pair is repeated inside this
container, which contains the actual value of the resource.
Example:
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Meta-data:
enabled=<boolean>
owner=<owner-name>
YANG module: example
YANG example:
container top {
leaf A {
type int32;
}
leaf B {
type boolean;
}
}
The client is retrieving the "top" data resource, and the server is
including datastore meta-data. Note that a query parameter to
request or suppress specific meta-data is not provided in RESTCONF.
GET /restconf/data/example:top HTTP/1.1
Host: example.com
Accept: application/yang.data+json
The server might respond as follows:
HTTP/1.1 200 OK
Date: Mon, 23 Apr 2012 17:01:00 GMT
Server: example-server
Content-Type: application/yang.data+json
{
"example:top": {
"@enabled" : "true",
"@owner" : "fred",
"A" : {
"@enabled" : "true",
"A" : 42
},
"B" : {
"@enabled" : "false",
"B" : true
}
}
}
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3.5. Return Status
Each message represents some sort of resource access. An HTTP
"Status-Line" header line is returned for each request. If a 4xx or
5xx range status code is returned in the Status-Line, then the error
information will be returned in the response, according to the format
defined in Section 6.1.
3.6. Message Caching
Since the datastore contents change at unpredictable times, responses
from a RESTCONF server generally SHOULD NOT be cached.
The server SHOULD include a "Cache-Control" header in every response
that specifies whether the response should be cached. A "Pragma"
header specifying "no-cache" MAY also be sent in case the
"Cache-Control" header is not supported.
Instead of using HTTP caching, the client SHOULD track the "ETag"
and/or "Last-Modified" headers returned by the server for the
datastore resource (or data resource if the server supports it). A
retrieval request for a resource can include the "If-None-Match"
and/or "If-Modified-Since" headers, which will cause the server to
return a "304 Not Modified" Status-Line if the resource has not
changed. The client MAY use the HEAD method to retrieve just the
message headers, which SHOULD include the "ETag" and "Last-Modified"
headers, if this meta-data is maintained for the target resource.
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4. Resources
The RESTCONF protocol operates on a hierarchy of resources, starting
with the top-level API resource itself. Each resource represents a
manageable component within the device.
A resource can be considered a collection of conceptual data and the
set of allowed methods on that data. It can contain child nodes that
are nested resources. The child resource types and methods allowed
on them are data-model specific.
A resource has its own media type identifier, represented by the
"Content-Type" header in the HTTP response message. A resource can
contain zero or more nested resources. A resource can be created and
deleted independently of its parent resource, as long as the parent
resource exists.
All RESTCONF resources are defined in this document except datastore
contents, protocol operations, and notification events. The syntax
and semantics for these resource types are defined in YANG modules.
The RESTCONF resources are accessed via a set of URIs defined in this
document. The set of YANG modules supported by the server will
determine the additional data model specific operations, top-level
data node resources, and notification event messages supported by the
server.
The resources used in the RESTCONF protocol are identified by the
"path" component in the request URI. Each operation is performed on
a target resource.
4.1. RESTCONF Resource Types
The RESTCONF protocol defines some application specific media types
to identify each of the available resource types. The following
resource types are defined in RESTCONF:
+-----------+----------------------------+
| Resource | Media Type |
+-----------+----------------------------+
| API | application/yang.api |
| Datastore | application/yang.datastore |
| Data | application/yang.data |
| Operation | application/yang.operation |
| Schema | application/yang |
| Stream | application/yang.stream |
+-----------+----------------------------+
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RESTCONF Media Types
4.2. Resource Discovery
A client SHOULD start by retrieving the top-level API resource, using
the entry point URI "/restconf".
The RESTCONF protocol does not include a resource discovery
mechanism. Instead, the definitions within the YANG modules
advertised by the server are used to construct a predictable
operation or data resource identifier.
The "depth" query parameter can be used to control how many
descendant levels should be included when retrieving sub-resources.
This parameter can be used with the GET method to discover sub-
resources within a particular resource.
4.3. API Resource (/restconf)
The API resource contains the state and access points for the
RESTCONF features. It is the top-level resource and has the media
type "application/yang.api+xml" or "application/yang.api+json". It
is accessible through the well-known URI "/restconf".
YANG Tree Diagram for "application/yang.api" Resource Type:
+--rw restconf
+--rw data
+--rw modules
| +--rw module [name revision]
| +--rw name yang:yang-identifier
| +--rw revision union
| +--rw schema? empty
| +--rw namespace inet:uri
| +--rw feature* yang:yang-identifier
| +--rw deviation* yang:yang-identifier
| +--rw submodule [name revision]
| +--rw name yang:yang-identifier
| +--rw revision union
| +--rw schema? empty
+--rw operations
+--rw streams
| +--rw stream [name]
| +--rw name string
| +--rw description? string
| +--rw replay-support? boolean
| +--rw replay-log-creation-time? yang:date-and-time
| +--rw events? empty
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+--ro version? enumeration
The "restconf" container definition in the "ietf-restconf" module
defined in Section 7 is used to specify the structure and syntax of
the conceptual sub-resources within the API resource.
This resource has the following child resources:
+----------------+--------------------------------+
| Child Resource | Description |
+----------------+--------------------------------+
| data | Contains all data resources |
| modules | YANG module information |
| operations | Data-model specific operations |
| streams | Notification event streams |
| version | RESTCONF API version |
+----------------+--------------------------------+
RESTCONF Resources
4.3.1. /restconf/data
This mandatory resource represents the combined configuration and
operational data resources that can be accessed by a client. It
cannot be created or deleted by the client. The datastore resource
type is defined in Section 4.4.
Example:
This example request by the client would retrieve only the non-
configuration data nodes that exist within the "library" resource,
using the "content" query parameter.
GET /restconf/data/example-jukebox:jukebox/library
?content=nonconfig HTTP/1.1
Host: example.com
Accept: application/yang.data+json
The server might respond:
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HTTP/1.1 200 OK
Date: Mon, 23 Apr 2012 17:01:30 GMT
Server: example-server
Cache-Control: no-cache
Pragma: no-cache
Content-Type: application/yang.data+json
{
"example-jukebox:library" : {
"artist-count" : 42,
"album-count" : 59,
"song-count" : 374
}
}
4.3.2. /restconf/modules
This mandatory resource contains the identifiers for the YANG data
model modules supported by the server.
The server MUST maintain a last-modified timestamp for this resource,
and return the "Last-Modified" header when this resource is retrieved
with the GET or HEAD methods.
The server SHOULD maintain an entity-tag for this resource, and
return the "ETag" header when this resource is retrieved with the GET
or HEAD methods.
4.3.2.1. /restconf/modules/module
This mandatory resource contains one list entry for each YANG data
model module supported by the server. There MUST be an instance of
this resource for every YANG module that is accessible via an
operation resource or a data resource.
The contents of the "module" resource are defined in the "module"
YANG list statement in Section 7.
The server MAY maintain a last-modified timestamp for each instance
of this resource, and return the "Last-Modified" header when this
resource is retrieved with the GET or HEAD methods. If not supported
then the timestamp for the parent "modules" resource MAY be used
instead.
The server MAY maintain an entity-tag for each instance of this
resource, and return the "ETag" header when this resource is
retrieved with the GET or HEAD methods. If not supported then the
timestamp for the parent "modules" resource MAY be used instead.
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4.3.3. /restconf/operations
This optional resource is a container that provides access to the
data-model specific protocol operations supported by the server. The
server MAY omit this resource if no data-model specific operations
are advertised.
Any data-model specific operations defined in the YANG modules
advertised by the server MAY be available as child nodes of this
resource.
Operation resources are defined in Section 4.6.
4.3.4. /restconf/streams
This optional resource is a container that provides access to the
notification event streams supported by the server. The server MAY
omit this resource if no notification event streams are supported.
The media type for this resource is "application/yang.api".
The server will populate this container with a stream list entry for
each stream type it supports. Each stream contains a leaf called
"events" which represents an event stream resource. The media type
for this resource is "application/yang.stream".
Stream resources are defined in Section 4.8. Notifications are
defined in Section 5.
4.3.5. /restconf/version
This sub-resource can be used by the client to identify the exact
version of the RESTCONF protocol implemented by the server. The same
server-wide response MUST be returned each time this resource is
retrieved.
The value is assigned by the server when the server is started. The
server MUST return the value "1.0" for this version of the RESTCONF
protocol. This resource is encoded with the rules for an
"enumeration" data type, using the "version" leaf definition in
Section 7.
4.4. Datastore Resource
The /restconf/data subtree represents the datastore resource type,
which is a collection of configuration and operational data nodes.
A "unified datastore" interface is used to simplify resource editing
for the client. The RESTCONF unified datastore is a conceptual
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interface to the native configuration datastores that are present on
the device.
The underlying NETCONF datastores (i.e., candidate, running, startup)
can be used to implement the unified datastore, but the server design
is not limited to the exact datastore procedures defined in NETCONF.
The "candidate" and "startup" datastores are not visible in the
RESTCONF protocol. Transaction management and configuration
persistence are handled by the server and not controlled by the
client.
4.4.1. Edit Collision Detection
Two "edit collision detection" mechanisms are provided in RESTCONF,
for datastore and data resources.
4.4.1.1. Timestamp
The last change time is maintained and the "Last-Modified" and "Date"
headers are returned in the response for a retrieval request. The
"If-Unmodified-Since" header can be used in edit operation requests
to cause the server to reject the request if the resource has been
modified since the specified timestamp.
The server MUST maintain a last-modified timestamp for this resource,
and return the "Last-Modified" header when this resource is retrieved
with the GET or HEAD methods. Only changes to configuration data
resources within the datastore affect this timestamp.
4.4.1.2. Entity tag
A unique opaque string is maintained and the "ETag" header is
returned in the response for a retrieval request. The "If-Match"
header can be used in edit operation requests to cause the server to
reject the request if the resource entity tag does not match the
specified value.
The server MUST maintain a resource entity tag for this resource, and
return the "ETag" header when this resource is retrieved with the GET
or HEAD methods. The resource entity tag MUST be changed to a new
previously unused value if changes to any configuration data
resources within the datastore are made.
A datastore resource can only be written directly with the PATCH
method. Only the configuration data resources within the datastore
resource can be edited directly with all methods.]
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Each RESTCONF edit of a datastore resource is saved to non-volatile
storage in an implementation-specific matter by the server. There is
no guarantee that configuration changes are saved immediately, or
that the saved configuration is always a mirror of the running
configuration.
4.5. Data Resource
A data resource represents a YANG data node that is a descendant node
of a datastore resource.
For configuration data resources, the server MAY maintain a last-
modified timestamp for the resource, and return the "Last-Modified"
header when it is retrieved with the GET or HEAD methods. If
maintained, the resource timestamp MUST be set to the current time
whenever the resource or any configuration resource within the
resource is altered.
For configuration data resources, the server MAY maintain a resource
entity tag for the resource, and return the "ETag" header when it is
retrieved as the target resource with the GET or HEAD methods. If
maintained, the resource entity tag MUST be updated whenever the
resource or any configuration resource within the resource is
altered.
A data resource can be retrieved with the GET method. Data resources
can be accessed via the "/restconf/data" entry point. This sub-tree
is used to retrieve and edit data resources.
A configuration data resource can be altered by the client with some
of all of the edit operations, depending on the target resource and
the specific operation. Refer to Section 2 for more details on edit
operations.
The resource definition version for a data resource is identified by
the revision date of the YANG module containing the YANG definition
for the data resource, specified in the /restconf/modules sub-tree.
4.5.1. Encoding YANG Instance Identifiers in the Request URI
In YANG, data nodes are named with an absolute XPath expression,
defined in [XPath] , starting from the document root to the target
resource. In RESTCONF, URL encoded Location header expressions are
used instead.
The YANG "instance-identifier" (i-i) data type is represented in
RESTCONF with the path expression format defined in this section.
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+-------+-------------------------------------------+
| Name | Comments |
+-------+-------------------------------------------+
| point | Insertion point is always a full i-i |
| path | Request URI path is a full or partial i-i |
+-------+-------------------------------------------+
RESTCONF instance-identifier Type Conversion
The "path" component of the request URI contains the absolute path
expression that identifies the target resource.
A predictable location for a data resource is important, since
applications will code to the YANG data model module, which uses
static naming and defines an absolute path location for all data
nodes.
A RESTCONF data resource identifier is not an XPath expression. It
is encoded from left to right, starting with the top-level data node,
according to the "api-path" rule in Section 4.5.1.1. The node name
of each ancestor of the target resource node is encoded in order,
ending with the node name for the target resource.
If a data node in the path expression is a YANG list node, then the
key values for the list (if any) are encoded according to the
"key-value" rule. If the list node is the target resource, then the
key values MAY be omitted, according to the operation. For example,
the POST method to create a new data resource for a list node does
not require key values to be present in the request URI.
The key leaf values for a data resource representing a YANG list MUST
be encoded as follows:
o The value of each leaf identified in the "key" statement is
encoded in order.
o All the components in the "key" statement MUST be encoded.
Partial instance identifiers are not supported.
o Each value is encoded using the "key-value" rule in
Section 4.5.1.1, according to the encoding rules for the data type
of the key leaf.
o An empty string can be a valid key value (e.g., "/top/list/key1//
key3").
o The "/" character MUST be URL-encoded (i.e., "%2F").
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o All whitespace MUST be URL-encoded.
o A "null" value is not allowed since the "empty" data type is not
allowed for key leafs.
o The XML encoding is defined in [RFC6020].
o The JSON encoding is defined in [I-D.lhotka-netmod-json].
o The entire "key-value" MUST be properly URL-encoded, according to
the rules defined in [RFC3986].
o resource URI values returned in Location headers for data
resources MUST identify the module name, even if there are no
conflicting local names when the resource is created. This
ensures the correct resource will be identified even if the server
loads a new module that the old client does not know about.
Examples:
[ lines wrapped for display purposes only ]
/restconf/data/example-jukebox:jukebox/library/
artist/Beatles/album
/restconf/data/example-list:newlist/17
/nextlist%2Ffoo%2Fbar%2Facme-list-ext%3Aext-leaf
/restconf/data/example-list:somelist/the%20key
/restconf/data/example-list:somelist/the%20key/address
4.5.1.1. ABNF For Data Resource Identifiers
The following ABNF syntax is used to construct RESTCONF path
identifiers:
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api-path = "/" |
("/" api-identifier
0*("/" (api-identifier | key-value )))
api-identifier = [module-name ":"] identifier
module-name = identifier
key-value = string
;; An identifier MUST NOT start with
;; (('X'|'x') ('M'|'m') ('L'|'l'))
identifier = (ALPHA / "_")
*(ALPHA / DIGIT / "_" / "-" / ".")
string = <an unquoted string>
[FIXME: the syntax for the select string is still TBD]
api-select = api-identifier
0*("/" (api-identifier | key-value ))
4.5.2. Defaults Handling
NETCONF has a rather complex model for handling default values for
leafs. RESTCONF attempts to avoid this complexity by restricting the
operations that can be applied to a resource.
If the target of a GET method is a data node that represents a leaf
that has a default value, and the leaf has not been given a value
yet, the server MUST return the default value that is in use by the
server.
If the target of a GET method is a data node that represents a
container or list that has any sub-resources with default values, for
the sub-resources that have not been given value yet, the server MAY
return the default values that are in use by the server.
4.6. Operation Resource
An operation resource represents an protocol operation defined with
the YANG "rpc" statement.
All operation resources share the same module namespace as any top-
level data resources, so the name of an operation resource cannot
conflict with the name of a top-level data resource defined within
the same module.
If 2 different YANG modules define the same "rpc" identifier, then
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the module name MUST be used in the request URI. For example, if
"module-A" and "module-B" both defined a "reset" operation, then
invoking the operation from "module-A" would be requested as follows:
POST /restconf/operations/module-A:reset HTTP/1.1
Server example.com
Any usage of an operation resource from the same module, with the
same name, refers to the same "rpc" statement definition. This
behavior can be used to design protocol operations that perform the
same general function on different resource types.
If the "rpc" statement has an "input" section, then a message body
MAY be sent by the client in the request, otherwise the request
message MUST NOT include a message body. If the "rpc" statement has
an "output" section, then a message body MAY be sent by the server in
the response. Otherwise the server MUST NOT include a message body
in the response message, and MUST send a "204 No Content" Status-Line
instead.
4.6.1. Encoding Operation Input Parameters
If the "rpc" statement has an "input" section, then the "input" node
is provided in the message body, corresponding to the YANG data
definition statements within the "input" section.
Example:
The following YANG definition is used for the examples in this
section.
rpc reboot {
input {
leaf delay {
units seconds;
type uint32;
default 0;
}
leaf message { type string; }
leaf language { type string; }
}
}
The client might send the following POST request message:
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POST /restconf/operations/example-ops:reboot HTTP/1.1
Host: example.com
Content-Type: application/yang.operation+json
{
"example-ops:input" : {
"delay" : 600,
"message" : "Going down for system maintenance",
"language" : "en-US"
}
}
The server might respond:
HTTP/1.1 204 No Content
Date: Mon, 25 Apr 2012 11:01:00 GMT
Server: example-server
4.6.2. Encoding Operation Output Parameters
If the "rpc" statement has an "output" section, then the "output"
node is provided in the message body, corresponding to the YANG data
definition statements within the "output" section.
Example:
The following YANG definition is used for the examples in this
section.
rpc get-reboot-info {
output {
leaf reboot-time {
units seconds;
type uint32;
}
leaf message { type string; }
leaf language { type string; }
}
}
The client might send the following POST request message:
POST /restconf/operations/example-ops:get-reboot-info HTTP/1.1
Host: example.com
Accept: application/yang.operation+json
The server might respond:
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HTTP/1.1 200 OK
Date: Mon, 25 Apr 2012 11:10:30 GMT
Server: example-server
Content-Type: application/yang.operation+json
{
"example-ops:output" : {
"reboot-time" : 30,
"message" : "Going down for system maintenance",
"language" : "en-US"
}
}
4.7. Schema Resource
If the server supports the "schema" leaf within the API then the
client can retrieve the YANG schema text for the associated YANG
module or submodule, using the GET method.
The client might send the following GET request message:
GET /restconf/modules/module/example-jukebox/2013-12-21/schema
HTTP/1.1
Host: example.com
Accept: application/yang
The server might respond:
HTTP/1.1 200 OK
Date: Mon, 25 Apr 2012 11:10:30 GMT
Server: example-server
Content-Type: application/yang
module example-jukebox {
namespace "http://example.com/ns/example-jukebox";
prefix "jbox";
// rest of YANG module content deleted...
}
4.8. Stream Resource
A stream resource represents a source for system generated event
notifications. Each stream is created and modified by the server
only. A client can retrieve a stream resource or initiate a long-
poll server sent event stream, using the procedure specified in
Section 5.3.
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A notification stream functions according to the NETCONF
Notifications specification [RFC5277]. The "ietf-restconf" YANG
module contains the "stream" list (/restconf/streams/stream) which
specifies the syntax and semantics of a stream resource.
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5. Notifications
The RESTCONF protocol supports YANG-defined event notifications. The
solution preserves aspects of NETCONF Event Notifications [RFC5277]
while utilizing the Server-Sent Events [wd-eventsource] transport
strategy.
5.1. Server Support
A RESTCONF server is not required to support RESTCONF notifications.
Clients may determine if a server supports RESTCONF notifications by
using the HTTP operation OPTIONS, HEAD, or GET on the "/restconf/
streams" resource described below. The server does not support
RESTCONF notifications if an HTTP error code is returned (e.g. 404
Not Found).
5.2. Event Streams
A RESTCONF server that supports notifications will populate a stream
resource for each notification delivery service access point. A
RESTCONF client can retrieve the list of supported event streams from
a RESTCONF server using the GET operation on the "/restconf/streams"
resource.
The "/restconf/streams" container definition in the "ietf-restconf"
module defined in Section 7 is used to specify the structure and
syntax of the conceptual sub-resources within the "streams" resource.
For example:
The client might send the following request:
GET /restconf/streams HTTP/1.1
Host: example.com
Accept: application/yang.api+xml
The server might send the following response:
HTTP/1.1 200 OK
Content-Type: application/yang.api+xml
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<streams xmlns="urn:ietf:params:xml:ns:yang:ietf-restconf">
<stream>
<name>NETCONF</name>
<description>default NETCONF event stream
</description>
<replay-support>true</replay-support>
<replay-log-creation-time>
2007-07-08T00:00:00Z
</replay-log-creation-time>
<events/>
</stream>
<stream>
<name>SNMP</name>
<description>SNMP notifications</description>
<replay-support>false</replay-support>
<events/>
</stream>
<stream>
<name>syslog-critical</name>
<description>Critical and higher severity
</description>
<replay-support>true</replay-support>
<replay-log-creation-time>
2007-07-01T00:00:00Z
</replay-log-creation-time>
<events/>
</stream>
</streams>
5.3. Subscribing to Receive Notifications
RESTCONF clients can subscribe to receive notifications by sending an
HTTP GET request for the "/restconf/streams/stream/<stream-name>"
resource, with the "Accept" type "text/event-stream". The server
will treat the connection as an event stream, using the Server Sent
Events [wd-eventsource] transport strategy.
The server MAY support query parameters for a GET method on this
resource. These parameters are specific to each notification stream.
For example:
GET /restconf/streams/stream/NETCONF/events HTTP/1.1
Host: example.com
Accept: text/event-stream
Cache-Control: no-cache
Connection: keep-alive
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A RESTCONF client MAY request the server compress the events using
the HTTP header field "Accept-Encoding". For instance:
GET /restconf/streams/stream/NETCONF/events HTTP/1.1
Host: example.com
Accept: text/event-stream
Cache-Control: no-cache
Connection: keep-alive
Accept-Encoding: gzip, deflate
5.3.1. NETCONF Event Stream
The server SHOULD support the "NETCONF" notification stream defined
in [RFC5277]. For this stream, RESTCONF notification subscription
requests MAY specify parameters indicating the events it wishes to
receive.
+------------+-------------------------+
| Name | Description |
+------------+-------------------------+
| start-time | replay event start time |
| stop-time | replay event stop time |
| filter | boolean content filter |
+------------+-------------------------+
NETCONF Stream Query Parameters
The semantics and syntax for these query parameters are defined in
the "query-parameters" YANG grouping in Section 7. The YANG encoding
MUST be converted to URL-encoded string for use in the request URI.
Refer to Appendix D.3.3 for filter parameter examples.
5.4. Receiving Event Notifications
RESTCONF notifications are encoded according to the definition of the
event stream. The NETCONF stream defined in [RFC5277] is encoded in
XML format.
The structure of the event data is based on the "notification"
element definition in section 4 of [RFC5277]. It MUST conform to the
"notification" YANG container definition in Section 7.
An example SSE notification encoded using XML:
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data: <notification
data: xmlns="urn:ietf:params:xml:ns:yang:ietf-restconf">
data: <event-time>2013-12-21T00:01:00Z</event-time>
data: <event xmlns="http://example.com/event/1.0">
data: <eventClass>fault</eventClass>
data: <reportingEntity>
data: <card>Ethernet0</card>
data: </reportingEntity>
data: <severity>major</severity>
data: </event>
data: </notification>
Since XML is not whitespace sensitive, the above message can be
encoded onto a single line.
For example: ('\' line wrapping added for formatting only)
data: <notification xmlns="urn:ietf:params:xml:ns:yang:ietf-rest\
conf"><event-time>2013-12-21T00:01:00Z</event-time><event xmlns="\
http://example.com/event/1.0"><eventClass>fault</eventClass><repo\
rtingEntity><card>Ethernet0</card></reportingEntity><severity>maj\
or</severity></event></notification>
The SSE specifications supports the following additional fields:
event, id and retry. A RESTCONF server MAY send the "retry" field
and, if it does, RESTCONF clients SHOULD use it. A RESTCONF server
SHOULD NOT send the "event" or "id" fields, as there are no
meaningful values that could be used for them that would not be
redundant to the contents of the notification itself. RESTCONF
servers that do not send the "id" field also do not need to support
the HTTP header "Last-Event-Id". RESTCONF servers that do send the
"id" field MUST still support the "startTime" query parameter as the
preferred means for a client to specify where to restart the event
stream.
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6. Error Reporting
HTTP Status-Lines are used to report success or failure for RESTCONF
operations. The <rpc-error> element returned in NETCONF error
responses contains some useful information. This error information
is adapted for use in RESTCONF, and error information is returned for
"4xx" class of status codes.
The following table summarizes the return status codes used
specifically by RESTCONF operations:
+---------------------------+---------------------------------------+
| Status-Line | Description |
+---------------------------+---------------------------------------+
| 100 Continue | POST accepted, 201 should follow |
| 200 OK | Success with response body |
| 201 Created | POST to create a resource success |
| 202 Accepted | POST to create a resource accepted |
| 204 No Content | Success without response body |
| 304 Not Modified | Conditional operation not done |
| 400 Bad Request | Invalid request message |
| 403 Forbidden | Access to resource denied |
| 404 Not Found | Resource target or resource node not |
| | found |
| 405 Method Not Allowed | Method not allowed for target |
| | resource |
| 409 Conflict | Resource or lock in use |
| 412 Precondition Failed | Conditional method is false |
| 413 Request Entity Too | too-big error |
| Large | |
| 414 Request-URI Too Large | too-big error |
| 415 Unsupported Media | non RESTCONF media type |
| Type | |
| 500 Internal Server Error | operation-failed |
| 501 Not Implemented | unknown-operation |
| 503 Service Unavailable | Recoverable server error |
+---------------------------+---------------------------------------+
HTTP Status Codes used in RESTCONF
Since an operation resource is defined with a YANG "rpc" statement, a
mapping between the NETCONF <error-tag> value and the HTTP status
code is needed. The specific error condition and response code to
use are data-model specific and might be contained in the YANG
"description" statement for the "rpc" statement.
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+-------------------------+-------------+
| <error-tag> | status code |
+-------------------------+-------------+
| in-use | 409 |
| invalid-value | 400 |
| too-big | 413 |
| missing-attribute | 400 |
| bad-attribute | 400 |
| unknown-attribute | 400 |
| bad-element | 400 |
| unknown-element | 400 |
| unknown-namespace | 400 |
| access-denied | 403 |
| lock-denied | 409 |
| resource-denied | 409 |
| rollback-failed | 500 |
| data-exists | 409 |
| data-missing | 409 |
| operation-not-supported | 501 |
| operation-failed | 500 |
| partial-operation | 500 |
| malformed-message | 400 |
+-------------------------+-------------+
Mapping from error-tag to status code
6.1. Error Response Message
When an error occurs for a request message on a data resource or an
operation resource, and a "4xx" class of status codes (except for
status code "403"), then the server SHOULD send a response body
containing the information described by the "errors" container
definition within the YANG module Section 7.
YANG Tree Diagram for <errors> Data:
+--ro errors
+--ro error
+--ro error-type enumeration
+--ro error-tag string
+--ro error-app-tag? string
+--ro (error-node)?
| +--:(error-path)
| | +--ro error-path? instance-identifier
| +--:(error-urlpath)
| +--ro error-urlpath? data-resource-identifier
+--ro error-message? string
+--ro error-info
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The semantics and syntax for RESTCONF error messages are defined in
the "errors" YANG grouping in Section 7.
Examples:
The following example shows an error returned for an "lock-denied"
error on a datastore resource.
POST /restconf/operations/example-ops:lock-datastore HTTP/1.1
Host: example.com
The server might respond:
HTTP/1.1 409 Conflict
Date: Mon, 23 Apr 2012 17:11:00 GMT
Server: example-server
Content-Type: application/yang.api+json
{
"ietf-restconf:errors": {
"error": {
"error-type": "protocol",
"error-tag": "lock-denied",
"error-message": "Lock failed, lock already held"
}
}
}
The following example shows an error returned for a "data-exists"
error on a data resource. The "jukebox" resource already exists so
it cannot be created.
The client might send:
POST /restconf/data/example-jukebox:jukebox HTTP/1.1
Host: example.com
The server might respond:
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HTTP/1.1 409 Conflict
Date: Mon, 23 Apr 2012 17:11:00 GMT
Server: example-server
Content-Type: application/yang.api+json
{
"ietf-restconf:errors": {
"error": {
"error-type": "protocol",
"error-tag": "data-exists",
"error-urlpath": "http://example.com/restconf/data/
example-jukebox:jukebox",
"error-message":
"Data already exists, cannot create new resource"
}
}
}
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7. RESTCONF module
The "ietf-restconf" module defines conceptual definitions within
groupings, which are not meant to be implemented as datastore
contents by a server.
The "ietf-yang-types" and "ietf-inet_types" modules from [RFC6991]
are used by this module for some type definitions.
RFC Ed.: update the date below with the date of RFC publication and
remove this note.
<CODE BEGINS> file "ietf-restconf@2014-02-13.yang"
module ietf-restconf {
namespace "urn:ietf:params:xml:ns:yang:ietf-restconf";
prefix "rc";
import ietf-yang-types { prefix yang; }
import ietf-inet-types { prefix inet; }
organization
"IETF NETCONF (Network Configuration) Working Group";
contact
"WG Web: <http://tools.ietf.org/wg/netconf/>
WG List: <mailto:netconf@ietf.org>
WG Chair: Bert Wijnen
<mailto:bertietf@bwijnen.net>
WG Chair: Mehmet Ersue
<mailto:mehmet.ersue@nsn.com>
Editor: Andy Bierman
<mailto:andy@yumaworks.com>
Editor: Martin Bjorklund
<mailto:mbj@tail-f.com>
Editor: Kent Watsen
<mailto:kwatsen@juniper.net>
Editor: Rex Fernando
<mailto:rex@cisco.com>";
description
"This module contains conceptual YANG specifications
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for the message and error content that is used in
RESTCONF protocol messages. A conceptual container
representing the RESTCONF API nodes is also defined
for the media type application/yang.api.
Note that the YANG definitions within this module do not
represent configuration data of any kind.
The YANG grouping statements provide a normative syntax
for XML and JSON message encoding purposes.
Copyright (c) 2013 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
(http://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX; see
the RFC itself for full legal notices.";
// RFC Ed.: replace XXXX with actual RFC number and remove this
// note.
// RFC Ed.: remove this note
// Note: extracted from draft-bierman-netconf-restconf-04.txt
// RFC Ed.: update the date below with the date of RFC publication
// and remove this note.
revision 2014-02-13 {
description
"Initial revision.";
reference
"RFC XXXX: RESTCONF Protocol.";
}
typedef data-resource-identifier {
type string {
length "1 .. max";
}
description
"Contains a Data Resource Identifier formatted string
to identify a specific data resource instance.
The document root for all data resources is a
datastore resource container. Each top-level YANG
data nodes supported by the server will be represented
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as a child node of the document root.
The canonical representation of a data resource identifier
includes the full server specification that is returned
in the Location header when a new data resource is created
with the POST method.
The abbreviated representation does not contain any server
location identification. Instead the identifier will start
with the '/' character to represent the datastore document
root for the data resource instance.
The server MUST accept either representation and SHOULD
return the canonical representation in any response message.";
reference
"RFC XXXX: [sec. 5.3.1.1 ABNF For Data Resource Identifiers]";
}
typedef revision-identifier {
type string {
pattern '\d{4}-\d{2}-\d{2}';
}
description
"Represents a specific date in YYYY-MM-DD format.
TBD: make pattern more precise to exclude leading zeros.";
}
grouping errors {
description
"A grouping that contains a YANG container
representing the syntax and semantics of a
YANG Patch errors report within a response message.";
container errors {
config false; // needed so list error does not need a key
description
"Represents an error report returned by the server if
a request results in an error.";
list error {
description
"An entry containing information about one
specific error that occurred while processing
a RESTCONF request.";
reference "RFC 6241, Section 4.3";
leaf error-type {
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type enumeration {
enum transport {
description "The transport layer";
}
enum rpc {
description "The rpc or notification layer";
}
enum protocol {
description "The protocol operation layer";
}
enum application {
description "The server application layer";
}
}
mandatory true;
description
"The protocol layer where the error occurred.";
}
leaf error-tag {
type string;
mandatory true;
description
"The enumerated error tag.";
}
leaf error-app-tag {
type string;
description
"The application-specific error tag.";
}
choice error-node {
description
"The server will return the location of the error node
in a format that is appropriate for the protocol.
If no specific node within the request message body
caused the error then this choice will not be present.";
leaf error-path {
type instance-identifier;
description
"The YANG instance identifier associated
with the error node. This leaf will only be
present if the error node is not a data resource,
e.g., the error node is an input parameter
for an operation resource.";
}
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leaf error-urlpath {
type data-resource-identifier;
description
"The target data resource identifier associated
with the error node. This leaf will only be
present if the error node is associated with
a data resource (either within the server or
in the request message).";
}
}
leaf error-message {
type string;
description
"A message describing the error.";
}
anyxml error-info {
description
"Arbitrary XML that represents a container
of additional information for the error report.";
}
}
}
} // grouping errors
grouping restconf {
description
"A grouping that contains a YANG container
representing the syntax and semantics of
the RESTCONF API resource.";
container restconf {
description
"Conceptual container representing the
application/yang.api resource type.";
container data {
description
"Container representing the application/yang.datastore
resource type. Represents the conceptual root of all
operational data and configuration data supported by
the server. The child nodes of this container can be
any data resource (application/yang.data), which are
defined as top-level data nodes from the YANG modules
advertised by the server in /restconf/modules.";
}
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container modules {
description
"Contains a list of module description entries.
These modules are currently loaded into the server.";
grouping common-leafs {
description
"Common parameters for YANG modules and submodules.";
leaf name {
type yang:yang-identifier;
description "The YANG module or submodule name.";
}
leaf revision {
type union {
type revision-identifier;
type string { length 0; }
}
description
"The YANG module or submodule revision date.
An empty string is used if no revision statement
is present in the YANG module or submodule.";
}
leaf schema {
type empty;
description
"Represents the YANG schema resource for this module
or submodule if it is available on the server.
This leaf will only be present if the server has
the schema available for retrieval. A GET
request with a target resource URI that identifies
this leaf will cause the server to return the YANG
schema text for the associated module or submodule.";
}
}
list module {
key "name revision";
description
"Each entry represents one module currently
supported by the server.";
uses common-leafs;
leaf namespace {
type inet:uri;
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mandatory true;
description
"The XML namespace identifier for this module.";
}
leaf-list feature {
type yang:yang-identifier;
description
"List of YANG feature names from this module that are
supported by the server.";
}
leaf-list deviation {
type yang:yang-identifier;
description
"List of YANG deviation module names used by this
server to modify the conformance of the module
associated with this entry.";
}
list submodule {
key "name revision";
description
"Each entry represents one submodule within the
parent module.";
uses common-leafs;
}
}
}
container operations {
description
"Container for all operation resources
(application/yang.operation),
Each resource is represented as an empty leaf with the
name of the RPC operation from the YANG rpc statement.
E.g.;
POST /restconf/operations/show-log-errors
leaf show-log-errors {
type empty;
}
";
}
container streams {
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description
"Container representing the notification event streams
supported by the server.";
reference
"RFC 5277, Section 3.4, <streams> element.";
list stream {
key name;
description
"Each entry describes an event stream supported by
the server.";
leaf name {
type string;
description "The stream name";
reference "RFC 5277, Section 3.4, <name> element.";
}
leaf description {
type string;
description "Description of stream content";
reference
"RFC 5277, Section 3.4, <description> element.";
}
leaf replay-support {
type boolean;
description
"Indicates if replay buffer supported for this stream";
reference
"RFC 5277, Section 3.4, <replaySupport> element.";
}
leaf replay-log-creation-time {
type yang:date-and-time;
description
"Indicates the time the replay log for this stream
was created.";
reference
"RFC 5277, Section 3.4, <replayLogCreationTime>
element.";
}
leaf events {
type empty;
description
"Represents the entry point for establishing
notification delivery via server sent events.";
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}
}
}
leaf version {
type enumeration {
enum "1.0" {
description
"Version 1.0 of the RESTCONF protocol.";
}
}
config false;
description
"Contains the RESTCONF protocol version.";
}
}
} // grouping restconf
grouping query-parameters {
description
"Contains conceptual definitions for the query string
parameters used in the RESTCONF protocol.";
leaf content {
type enumeration {
enum config {
description
"Return only configuration descendant data nodes";
}
enum nonconfig {
description
"Return only non-configuration descendant data nodes";
}
enum all {
description
"Return all descendant data nodes";
}
}
description
"The content parameter controls how descendant nodes of
the requested data nodes will be processed in the reply.
This parameter is only allowed for GET methods on
datastore and data resources. A 400 Bad Request error
is returned if used for other methods or resource types.
The default value is determined by the config-stmt
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value of the requested data nodes. If 'false', then
the default is 'nonconfig'. If 'true' then the
default is 'config'.";
}
leaf depth {
type union {
type enumeration {
enum unbounded {
description "All sub-resources will be returned.";
}
}
type uint32 {
range "1..max";
}
}
default unbounded;
description
"The 'depth' parameter is used to specify the number
of nest levels returned in a response for a GET method.
The first nest-level consists of the requested data node
itself. Any child nodes which are contained within
a parent node have a depth value that is 1 greater than
its parent.
This parameter is only allowed for GET methods on api,
datastore, and data resources. A 400 Bad Request error
is returned if used for other methods or resource types.
By default, the server will include all sub-resources
within a retrieved resource, which have the same resource
type as the requested resource. Only one level of
sub-resources with a different media type than the target
resource will be returned.";
}
leaf filter {
type yang:xpath1.0;
description
"The 'filter' parameter is used to indicate which subset of
all possible events are of interest. If not present, all
events not precluded by other parameters will be sent.
This parameter is only allowed for GET methods on a
text/event-stream data resource. A 400 Bad Request error
is returned if used for other methods or resource types.
The format of this parameter is an XPath expression, and
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is evaluated in the following context:
o The set of namespace declarations is the set of
prefix and namespace pairs for all supported YANG
modules, where the prefix is the YANG module name, and
the namespace is as defined by the 'namespace' statement
in the YANG module.
o The function library is the core function library defined
in XPATH.
o The set of variable bindings is empty.
o The context node is the root node
The filter is used as defined in [RFC5277], section 3.6.
If the boolean result of the expression is true when applied
to the conceptual 'notification' document root, then the
notification event is delivered to the client.";
}
leaf insert {
type enumeration {
enum first {
description "Insert the new data as the new first entry.";
}
enum last {
description "Insert the new data as the new last entry.";
}
enum before {
description
"Insert the new data before the insertion point,
specified by the value of the 'point' parameter.";
}
enum after {
description
"Insert the new data after the insertion point,
specified by the value of the 'point' parameter.";
}
}
default last;
description
"The 'insert' parameter is used to specify how a
resource should be inserted within a user-ordered list.
This parameter is only supported for the POST and PUT
methods. It is also only supported if the target
resource is a data resource, and that data represents
a YANG list or leaf-list that is ordered by the user.
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If the values 'before' or 'after' are used,
then a 'point' query parameter for the insertion
parameter MUST also be present, or a 400 Bad Request
error is returned.";
}
leaf point {
type data-resource-identifier;
description
"The 'point' parameter is used to specify the
insertion point for a data resource that is being
created or moved within a user ordered list or leaf-list.
This parameter is only supported for the POST and PUT
methods. It is also only supported if the target
resource is a data resource, and that data represents
a YANG list or leaf-list that is ordered by the user.
If the 'insert' query parameter is not present, or has
a value other than 'before' or 'after', then a 400
Bad Request error is returned.
This parameter contains the instance identifier of the
resource to be used as the insertion point for a
POST or PUT method.";
}
leaf select {
type string {
length "1 .. max";
}
description
"The 'select' query parameter is used to specify an
expression which can represent a subset of all data nodes
within the target resource. It contains an expression
string, using the target resource as the context node.
The encoding for the select parameter is still TBD.
This parameter is only allowed for GET methods on api,
datastore, and data resources. A 400 Bad Request error
is returned if used for other methods or resource types.
If XPath:
The string is an XPath expression that will be evaluated
using the target resource instance as the context node
and the document root. It is expected to return a node-set
result representing the descendants within the context
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node that should be returned in a GET response.";
}
leaf start-time {
type yang:date-and-time;
description
"The 'start-time' parameter is used to trigger
the notification replay feature and indicate
that the replay should start at the time specified.
If the stream does not support replay, per the
'replay-support' attribute returned by
the /restconf/streams resource, then the server MUST
return the HTTP error code 400 Bad Request.
This parameter is only allowed for GET methods on a
text/event-stream data resource. A 400 Bad Request error
is returned if used for other methods or resource types.
If this parameter is not present, then a replay subscription
is not begin requested. It is not valid to specify start
times that are later than the current time. If the value
specified is earlier than the log can support, the replay
will begin with the earliest available notification";
}
leaf stop-time {
type yang:date-and-time;
description
"The 'stop-time' parameter is used with the
replay feature to indicate the newest notifications of
interest. This parameter MUST be used with and have a
value later than the 'start-time' parameter.
This parameter is only allowed for GET methods on a
text/event-stream data resource. A 400 Bad Request error
is returned if used for other methods or resource types.
If this parameter is not present, the notifications will
continue until the subscription is terminated.
Values in the future are valid.";
}
} // grouping query-parameters
grouping notification {
description
"Contains the notification message wrapper definition.";
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container notification {
description
"RESTCONF notification message wrapper.";
leaf event-time {
type yang:date-and-time;
mandatory true;
description
"The time the event was generated by the
event source.";
reference
"RFC 5277, section 4, <eventTime> element.";
}
/* The YANG-specific notification container is encoded
* after the 'event-time' element. The format
* corresponds to the notificationContent element
* in RFC 5277, section 4. For example:
*
* module example-one {
* ...
* notification event1 { ... }
*
* }
*
* Encoded as element 'event1' in the namespace
* for module 'example-one'.
*/
}
} // grouping notification
}
<CODE ENDS>
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8. IANA Considerations
8.1. YANG Module Registry
This document registers one URI in the IETF XML registry [RFC3688].
Following the format in RFC 3688, the following registration is
requested to be made.
URI: urn:ietf:params:xml:ns:yang:ietf-restconf
Registrant Contact: The NETMOD WG of the IETF.
XML: N/A, the requested URI is an XML namespace.
This document registers one YANG module in the YANG Module Names
registry [RFC6020].
name: ietf-restconf
namespace: urn:ietf:params:xml:ns:yang:ietf-restconf
prefix: rc
// RFC Ed.: replace XXXX with RFC number and remove this note
reference: RFC XXXX
8.2. application/yang Media Sub Types
The parent MIME media type for RESTCONF resources is application/
yang, which is defined in [RFC6020]. This document defines the
following sub-types for this media type.
- api
- data
- datastore
- operation
- stream
Type name: application
Subtype name: yang.xxx
Required parameters: TBD
Optional parameters: TBD
Encoding considerations: TBD
Security considerations: TBD
Interoperability considerations: TBD
// RFC Ed.: replace XXXX with RFC number and remove this note
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Published specification: RFC XXXX
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9. Security Considerations
TBD
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10. References
10.1. Normative References
[I-D.lhotka-netmod-json]
Lhotka, L., "Modeling JSON Text with YANG",
draft-lhotka-netmod-yang-json-02 (work in progress),
September 2013.
[JSON] Bray, T., Ed., "The JSON Data Interchange Format",
draft-ietf-json-rfc4627bis-10 (work in progress),
December 2013.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2396] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifiers (URI): Generic Syntax", RFC 2396,
August 1998.
[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
January 2004.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, January 2005.
[RFC5277] Chisholm, S. and H. Trevino, "NETCONF Event
Notifications", RFC 5277, July 2008.
[RFC5789] Dusseault, L. and J. Snell, "PATCH Method for HTTP",
RFC 5789, March 2010.
[RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the
Network Configuration Protocol (NETCONF)", RFC 6020,
October 2010.
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, June 2011.
[RFC6536] Bierman, A. and M. Bjorklund, "Network Configuration
Protocol (NETCONF) Access Control Model", RFC 6536,
March 2012.
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[RFC6991] Schoenwaelder, J., "Common YANG Data Types", RFC 6991,
July 2013.
[W3C.REC-xml-20081126]
Yergeau, F., Maler, E., Paoli, J., Sperberg-McQueen, C.,
and T. Bray, "Extensible Markup Language (XML) 1.0 (Fifth
Edition)", World Wide Web Consortium Recommendation REC-
xml-20081126, November 2008,
<http://www.w3.org/TR/2008/REC-xml-20081126>.
[wd-eventsource]
Hickson, I., "Server-Sent Events", December 2012.
10.2. Informative References
[XPath] Clark, J. and S. DeRose, "XML Path Language (XPath)
Version 1.0", World Wide Web Consortium
Recommendation REC-xpath-19991116, November 1999,
<http://www.w3.org/TR/1999/REC-xpath-19991116>.
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Appendix A. Change Log
-- RFC Ed.: remove this section before publication.
A.1. 03 to 04
o Changed term RESTful to REST-like
o Clarified SSE section
o Clarified access control section
o Clarified return code test for some HTTP methods
o Fixed 2 examples that were wrong
A.2. 02 to 03
o Move YANG Patch to separate document
o Remove some introduction text
o Move most framework text into other sections
o Move notifications into its own section
o Remove fields; all YANG node types are sub-resources
o Add schema retrieval via /restconf/modules/module/schema resource
o Add submodule support to /restconf/modules/module resource
o Move some examples to appendix
o Add canonical representation for data-resource-identifier typedef
o Move query string definitions to YANG module
o Removed "format" query parameter
o Removed user-selected XML/JSON encoding for events. Event streams
define a fixed encoding. It is not user-configurable.
o Clarified that query parameters for SSE event streams are specific
to the stream definition; start-time, stop-time, and filter only
apply to the NETCONF stream;
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o Change operation input and output media type from application/
yang.data to application/yang.data.
o Fix some bugs and typos
A.3. 01 to 02
o Added Notification Model (section 2.2)
o Remove error-action from YANG Patch
o Add "comment" and "ok" leafs to yang-patch-status container
o Fixed YANG Patch JSON example syntax
o Added stream resource type and streams container to /restconf
container
o Removed "vnd" from media type definitions
o Changed yang-patch edit list from ascending uint32 key to an
arbitrary string key and an ordered-by user list.
o Several clarifications and corrections
o Add YANG tree diagrams
o Add application/yang.patch-status media type
o Remove redundant "global-errors" container from
"yang-patch-status" container
o Split the /restconf/datastore entry point into 2 entry points
(config and operational)
o Remove the "config" parameter since it is no longer needed after
datastore is split
A.4. 00 to 01
o Removed incorrect /.well-known URI prefix.
o Remove incorrect IANA request for well-known URI.
o Clarified that API resource type nodes are defined in the ietf-
restconf namespace.
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o Changed CamelCase names in example-jukebox.yang to lowercase, and
updated examples.
o Updated and corrected YANG types in ietf-restconf module.
A.5. YANG-API-01 to RESTCONF-00
o Protocol renamed from YANG-API to RESTCONF
o Fields are clarified. Containers and lists are sub-resources.
All other YANG data node types are fields within a parent
resource.
o The 'optional-key' YANG extension has been removed.
o The default value is returned by the server if the target resource
represents a missing data node but the server is using a default
value for the leaf.
o The default for the 'depth' parameter has been changed from '1' to
'unbounded'. The depth is only limited if an integer value for
this parameter is specified by the client.
o The default for the 'format' parameter has been changed from
'json' to 'xml'.
o expanded introduction
o removed transactions
o removed capabilities
o removed usage of Range and IfRange headers
o simplified editing model
o removed global protocol operations from ietf-restconf.yang
o changed RPC operation terminology to protocol operation
o updated JSON draft reference
o updated IANA section
o added YANG Patch
o added YANG definitions to ietf-restconf.yang
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o added Kent Watsen and Rex Fernando as co-authors
o updated YANG modules so they pass pyang --ietf checking
o changed examples so resource URIs use the module name variant to
identify data resources
o changed depth behavior so the entire server contents are not
returned for "GET /restconf"; Server will stop at new resource
type; e.g. yang.api --> yang.datastore returns the datastore as an
empty node; yang.api --> yang.operation returns the operation name
as an empty node;
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Appendix B. Open Issues
B.1. message-id
o There is no "message-id" field in a RESTCONF message. Is a
message identifier needed? If so, should either the "Message-ID"
or "Content-ID" header from RFC 2392 be used for this purpose?
B.2. select parameter
o What syntax should be used for the "select" query parameter? The
current choices are "XPath" and "path-expr". Perhaps an
additional parameter to identify the select string format is
needed to allow extensibility?
B.3. server support verification
o Are all header lines used by RESTCONF supported by common
application frameworks, such as FastCGI and WSGI? If not, then
should query parameters be used instead, since the QUERY_STRING is
widely available to WEB applications?
B.4. error media type
o Should the <errors> element returned in error responses be a
separate media type?
B.5. additional datastores
o How should additional datastores be supported, which may be added
to the NETCONF/NETMOD framework in the future?
B.6. PATCH media type discovery
o How does a client know which PATCH media types are supported by
the server in addition to application/yang.data and application/
yang.patch?
B.7. RESTCONF version
o Is the /restconf/version field considered meta-data? Should it be
returned as XRD (Extensible Resource Descriptor)? In addition or
instead of the version field? Should this be the ietf-restconf
YANG module revision date, instead of the string 1.0?
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B.8. YANG to resource mapping
o Since data resources can only be YANG containers or lists, what
should be done about top-level YANG data nodes that are not
containers or lists? Are they allowed in RESTCONF?
o Can a choice be a resource? YANG choices are invisible to
RESTCONF at this time.
B.9. .well-known usage
o Does RESTCONF need to Use a .well-known link relation to to re-map
API entry point?
The client first discovers the server's root for the RESTCONF API.
In this example, it is "/api/restconf":
Request
-------
GET /.well-known/host-meta users HTTP/1.1
Host: example.com
Accept: application/xrd+xml
Response
--------
HTTP/1.1 200 OK
Content-Type: application/xrd+xml
Content-Length: nnn
<XRD xmlns='http://docs.oasis-open.org/ns/xri/xrd-1.0'>
<Link rel='restconf' href='/api/restconf'/>
</XRD>
Once discovering the RESTCONF API root, the client MUST prepend it to
any access to a RESTCONF resource:
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Request
-------
GET /api/restconf/version HTTP/1.1
Host: example.com
Accept: application/yang.api+json
Response
--------
HTTP/1.1 200 OK
Date: Mon, 23 Apr 2012 17:01:00 GMT
Server: example-server
Cache-Control: no-cache
Pragma: no-cache
Last-Modified: Sun, 22 Apr 2012 01:00:14 GMT
Content-Type: application/yang.api+json
{ "version": "1.0" }
B.10. _self links for HATEOAS support
o Should there be a mode where the client can request that the
resource identifier is returned in a GET request?
B.11. netconf-state monitoring support
o Should long-term RESTCONF operations (i.e. SSE long-poll) be
considered sessions with regards to NETCONF monitoring "session"
list? If so, what text is needed in RESTCONF draft to standardize
the RESTCONF session entries?
B.12. secure transport
o Details to support secure operation over TLS are needed
o Security considerations need to be written
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Appendix C. Example YANG Module
The example YANG module used in this document represents a simple
media jukebox interface.
YANG Tree Diagram for "example-jukebox" Module
+--rw jukebox?
+--rw library
| +--rw artist [name]
| | +--rw name string
| | +--rw album [name]
| | +--rw name string
| | +--rw genre? identityref
| | +--rw year? uint16
| | +--rw song [name]
| | +--rw name string
| | +--rw location string
| | +--rw format? string
| | +--rw length? uint32
| +--ro artist-count? uint32
| +--ro album-count? uint32
| +--ro song-count? uint32
+--rw playlist [name]
| +--rw name string
| +--rw description? string
| +--rw song [index]
| +--rw index uint32
| +--rw id instance-identifier
+--rw player
+--rw gap? decimal64
rpcs:
+---x play
+--ro input
+--ro playlist string
+--ro song-number uint32
C.1. example-jukebox YANG Module
module example-jukebox {
namespace "http://example.com/ns/example-jukebox";
prefix "jbox";
import ietf-restconf { prefix rc; }
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organization "Example, Inc.";
contact "support at example.com";
description "Example Jukebox Data Model Module";
revision "2013-12-21" {
description "Initial version.";
reference "example.com document 1-4673";
}
identity genre {
description "Base for all genre types";
}
// abbreviated list of genre classifications
identity alternative {
base genre;
description "Alternative music";
}
identity blues {
base genre;
description "Blues music";
}
identity country {
base genre;
description "Country music";
}
identity jazz {
base genre;
description "Jazz music";
}
identity pop {
base genre;
description "Pop music";
}
identity rock {
base genre;
description "Rock music";
}
container jukebox {
presence
"An empty container indicates that the jukebox
service is available";
description
"Represents a jukebox resource, with a library, playlists,
and a play operation.";
container library {
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description "Represents the jukebox library resource.";
list artist {
key name;
description
"Represents one artist resource within the
jukebox library resource.";
leaf name {
type string {
length "1 .. max";
}
description "The name of the artist.";
}
list album {
key name;
description
"Represents one album resource within one
artist resource, within the jukebox library.";
leaf name {
type string {
length "1 .. max";
}
description "The name of the album.";
}
leaf genre {
type identityref { base genre; }
description
"The genre identifying the type of music on
the album.";
}
leaf year {
type uint16 {
range "1900 .. max";
}
description "The year the album was released";
}
list song {
key name;
description
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"Represents one song resource within one
album resource, within the jukebox library.";
leaf name {
type string {
length "1 .. max";
}
description "The name of the song";
}
leaf location {
type string;
mandatory true;
description
"The file location string of the
media file for the song";
}
leaf format {
type string;
description
"An identifier string for the media type
for the file associated with the
'location' leaf for this entry.";
}
leaf length {
type uint32;
units "seconds";
description
"The duration of this song in seconds.";
}
} // end list 'song'
} // end list 'album'
} // end list 'artist'
leaf artist-count {
type uint32;
units "songs";
config false;
description "Number of artists in the library";
}
leaf album-count {
type uint32;
units "albums";
config false;
description "Number of albums in the library";
}
leaf song-count {
type uint32;
units "songs";
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config false;
description "Number of songs in the library";
}
} // end library
list playlist {
key name;
description
"Example configuration data resource";
leaf name {
type string;
description
"The name of the playlist.";
}
leaf description {
type string;
description
"A comment describing the playlist.";
}
list song {
key index;
ordered-by user;
description
"Example nested configuration data resource";
leaf index { // not really needed
type uint32;
description
"An arbitrary integer index for this
playlist song.";
}
leaf id {
type rc:data-resource-identifier;
mandatory true;
description
"Song identifier. Must identify an instance of
/jukebox/library/artist/album/song/name.";
}
}
}
container player {
description
"Represents the jukebox player resource.";
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leaf gap {
type decimal64 {
fraction-digits 1;
range "0.0 .. 2.0";
}
units "tenths of seconds";
description "Time gap between each song";
}
}
}
rpc play {
description "Control function for the jukebox player";
input {
leaf playlist {
type string;
mandatory true;
description "playlist name";
}
leaf song-number {
type uint32;
mandatory true;
description "Song number in playlist to play";
}
}
}
}
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Appendix D. RESTCONF Message Examples
The examples within this document use the normative YANG module
defined in Section 7 and the non-normative example YANG module
defined in Appendix C.1.
This section shows some typical RESTCONF message exchanges.
D.1. Resource Retrieval Examples
D.1.1. Retrieve the Top-level API Resource
The client may start by retrieving the top-level API resource, using
the entry point URI "/restconf".
GET /restconf HTTP/1.1
Host: example.com
Accept: application/yang.api+json
The server might respond as follows:
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HTTP/1.1 200 OK
Date: Mon, 23 Apr 2012 17:01:00 GMT
Server: example-server
Content-Type: application/yang.api+json
{
"ietf-restconf:restconf": {
"data" : [ null ],
"modules": {
"module": [
{
"name" : "example-jukebox",
"revision" : "2013-12-21",
"namespace" : "http://example.com/ns/example-jukebox",
"schema" : [ null ]
}
]
},
"operations" : {
"play" : [ null ]
},
"streams" : {
"stream" : [
{
"name" : "NETCONF",
"description" : "default NETCONF event stream",
"replay-support" : true,
"replay-log-creation-time:" : "2007-07-08T00:00:00Z",
"events" : [ null ]
}
]
},
"version": "1.0"
}
}
To request that the response content to be encoded in XML, the
"Accept" header can be used, as in this example request:
GET /restconf HTTP/1.1
Host: example.com
Accept: application/yang.api+xml
The server will return the same response either way, which might be
as follows :
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HTTP/1.1 200 OK
Date: Mon, 23 Apr 2012 17:01:00 GMT
Server: example-server
Cache-Control: no-cache
Pragma: no-cache
Content-Type: application/yang.api+xml
<restconf xmlns="urn:ietf:params:xml:ns:yang:ietf-restconf">
<data/>
<modules>
<module>
<name>example-jukebox</name>
<revision>2013-12-21</revision>
<namespace>
http://example.com/ns/example-jukebox
</namespace>
<schema />
</module>
</modules>
<operations>
<play xmlns="http://example.com/ns/example-jukebox"/>
</operations>
<streams>
<stream>
<name>NETCONF</name>
<description>default NETCONF event stream
</description>
<replay-support>true</replay-support>
<replay-log-creation-time>
2007-07-08T00:00:00Z
</replay-log-creation-time>
<events/>
</stream>
</streams>
<version>1.0</version>
</restconf>
D.1.2. Retrieve The Server Module Information
In this example the client is retrieving the modules resource from
the server in JSON format:
GET /restconf/modules HTTP/1.1
Host: example.com
Accept: application/yang.api+json
The server might respond as follows.
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HTTP/1.1 200 OK
Date: Mon, 23 Apr 2012 17:01:00 GMT
Server: example-server
Cache-Control: no-cache
Pragma: no-cache
Last-Modified: Sun, 22 Apr 2012 01:00:14 GMT
Content-Type: application/yang.api+json
{
"ietf-restconf:modules": {
"module": [
{
"name" : "foo",
"revision" : "2012-01-02",
"schema" : [null],
"namespace" : "http://example.com/ns/foo",
"feature" : [ "feature1", "feature2" ]
},
{
"name" : "foo-types",
"revision" : "2012-01-05",
"schema" : [null],
"namespace" : "http://example.com/ns/foo-types"
},
{
"name" : "bar",
"revision" : "2012-11-05",
"schema" : [null],
"namespace" : "http://example.com/ns/bar",
"feature" : [ "bar-ext" ],
"submodule" : [
{
"name" : "bar-submod1",
"revision" : "2012-11-05",
"schema" : [null]
},
{
"name" : "bar-submod2",
"revision" : "2012-11-05",
"schema" : [null]
}
]
}
]
}
}
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D.2. Edit Resource Examples
D.2.1. Create New Data Resources
To create a new "artist" resource within the "library" resource, the
client might send the following request.
POST /restconf/data/example-jukebox:jukebox/library HTTP/1.1
Host: example.com
Content-Type: application/yang.data+json
{ "example-jukebox:artist" : {
"name" : "Foo Fighters"
}
}
If the resource is created, the server might respond as follows.
Note that the "Location" header line is wrapped for display purposes
only:
HTTP/1.1 201 Created
Date: Mon, 23 Apr 2012 17:02:00 GMT
Server: example-server
Location: http://example.com/restconf/data/
example-jukebox:jukebox/library/artist/Foo%20Fighters
Last-Modified: Mon, 23 Apr 2012 17:02:00 GMT
ETag: b3830f23a4c
To create a new "album" resource for this artist within the "jukebox"
resource, the client might send the following request. Note that the
request URI header line is wrapped for display purposes only:
POST /restconf/data/example-jukebox:jukebox/
library/artist/Foo%20Fighters HTTP/1.1
Host: example.com
Content-Type: application/yang.data+json
{
"example-jukebox:album" : {
"name" : "Wasting Light",
"genre" : "example-jukebox:alternative",
"year" : 2012 # note this is the wrong date
}
}
If the resource is created, the server might respond as follows.
Note that the "Location" header line is wrapped for display purposes
only:
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HTTP/1.1 201 Created
Date: Mon, 23 Apr 2012 17:03:00 GMT
Server: example-server
Location: http://example.com/restconf/data/
example-jukebox:jukebox/library/artist/Foo%20Fighters/
album/Wasting%20Light
Last-Modified: Mon, 23 Apr 2012 17:03:00 GMT
ETag: b8389233a4c
D.2.2. Detect Resource Entity Tag Change
In this example, the server just supports the mandatory datastore
last-changed timestamp. The client has previously retrieved the
"Last-Modified" header and has some value cached to provide in the
following request to patch an "album" list entry with key value
"Wasting Light". Only the "year" field is being updated.
PATCH /restconf/data/example-jukebox:jukebox/
library/artist/Foo%20Fighters/album/Wasting%20Light/year
HTTP/1.1
Host: example.com
Accept: application/yang.data+json
If-Unmodified-Since: Mon, 23 Apr 2012 17:01:00 GMT
Content-Type: application/yang.data+json
{ "example-jukebox:year" : "2011" }
In this example the datastore resource has changed since the time
specified in the "If-Unmodified-Since" header. The server might
respond:
HTTP/1.1 412 Precondition Failed
Date: Mon, 23 Apr 2012 19:01:00 GMT
Server: example-server
Last-Modified: Mon, 23 Apr 2012 17:45:00 GMT
ETag: b34aed893a4c
D.3. Query String Parameter Examples
D.3.1. "content" Parameter
The "content" parameter is used to select the type of data sub-
resources (configuration and/or not configuration) that are returned
by the server for a GET method request.
In this example, a simple YANG list that has configuration and non-
configuration sub-resources.
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container events
list event {
key name;
leaf name { type string; }
leaf description { type string; }
leaf event-count {
type uint32;
config false;
}
}
}
Example 1: content=all
To retrieve all the sub-resources, the "content" parameter is set to
"all". The client might send:
GET /restconf/data/example-events:events?content=all
HTTP/1.1
Host: example.com
Accept: application/yang.data+json
The server might respond:
HTTP/1.1 200 OK
Date: Mon, 23 Apr 2012 17:11:30 GMT
Server: example-server
Cache-Control: no-cache
Pragma: no-cache
Content-Type: application/yang.data+json
{
"example-events:events" : {
"event" : [
{
"name" : "interface-up",
"description" : "Interface up notification count",
"event-count" : 42
},
{
"name" : "interface-down",
"description" : "Interface down notification count",
"event-count" : 4
}
]
}
}
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Example 2: content=config
To retrieve only the configuration sub-resources, the "content"
parameter is set to "config" or omitted since this is the default
value. Note that the "ETag" and "Last-Modified" headers are only
returned if the content parameter value is "config".
GET /restconf/data/example-events:events?content=config
HTTP/1.1
Host: example.com
Accept: application/yang.data+json
The server might respond:
HTTP/1.1 200 OK
Date: Mon, 23 Apr 2012 17:11:30 GMT
Server: example-server
Last-Modified: Mon, 23 Apr 2012 13:01:20 GMT
ETag: eeeada438af
Cache-Control: no-cache
Pragma: no-cache
Content-Type: application/yang.data+json
{
"example-events:events" : {
"event" : [
{
"name" : "interface-up",
"description" : "Interface up notification count"
},
{
"name" : "interface-down",
"description" : "Interface down notification count"
}
]
}
}
Example 3: content=non-config
To retrieve only the non-configuration sub-resources, the "content"
parameter is set to "non-config". Note that configuration ancestors
(if any) and list key leafs (if any) are also returned. The client
might send:
GET /restconf/data/example-events:events?content=non-config
HTTP/1.1
Host: example.com
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Accept: application/yang.data+json
The server might respond:
HTTP/1.1 200 OK
Date: Mon, 23 Apr 2012 17:11:30 GMT
Server: example-server
Cache-Control: no-cache
Pragma: no-cache
Content-Type: application/yang.data+json
{
"example-events:events" : {
"event" : [
{
"name" : "interface-up",
"event-count" : 42
},
{
"name" : "interface-down",
"event-count" : 4
}
]
}
}
D.3.2. "depth" Parameter
The "depth" parameter is used to limit the number of levels of sub-
resources that are returned by the server for a GET method request.
This example shows how different values of the "depth" parameter
would affect the reply content for retrieval of the top-level
"jukebox" data resource.
Example 1: depth=unbounded
To retrieve all the sub-resources, the "depth" parameter is not
present or set to the default value "unbounded". Note that some
strings are wrapped for display purposes only.
GET /restconf/data/example-jukebox:jukebox?depth=unbounded
HTTP/1.1
Host: example.com
Accept: application/yang.data+json
The server might respond:
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HTTP/1.1 200 OK
Date: Mon, 23 Apr 2012 17:11:30 GMT
Server: example-server
Cache-Control: no-cache
Pragma: no-cache
Content-Type: application/yang.data+json
{
"example-jukebox:jukebox" : {
"library" : {
"artist" : [
{
"name" : "Foo Fighters",
"album" : [
{
"name" : "Wasting Light",
"genre" : "example-jukebox:alternative",
"year" : 2011,
"song" : [
{
"name" : "Wasting Light",
"location" :
"/media/foo/a7/wasting-light.mp3",
"format" : "MP3",
"length" " 286
},
{
"name" : "Rope",
"location" : "/media/foo/a7/rope.mp3",
"format" : "MP3",
"length" " 259
}
]
}
]
}
]
},
"playlist" : [
{
"name" : "Foo-One",
"description" : "example playlist 1",
"song" : [
{
"index" : 1,
"id" : "http://example.com/restconf/data/
example-jukebox:jukebox/library/artist/
Foo%20Fighters/album/Wasting%20Light/
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song/Rope"
},
{
"index" : 2,
"id" : "http://example.com/restconf/data/
example-jukebox:jukebox/library/artist/
Foo%20Fighters/album/Wasting%20Light/song/
Bridge%20Burning"
}
]
}
],
"player" : {
"gap" : 0.5
}
}
}
Example 2: depth=1
To determine if 1 or more resource instances exist for a given target
resource, the value "1" is used.
GET /restconf/data/example-jukebox:jukebox?depth=1 HTTP/1.1
Host: example.com
Accept: application/yang.data+json
The server might respond:
HTTP/1.1 200 OK
Date: Mon, 23 Apr 2012 17:11:30 GMT
Server: example-server
Cache-Control: no-cache
Pragma: no-cache
Content-Type: application/yang.data+json
{
"example-jukebox:jukebox" : [null]
}
Example 3: depth=3
To limit the depth level to the target resource plus 2 sub-resource
layers the value "3" is used.
GET /restconf/data/example-jukebox:jukebox?depth=3 HTTP/1.1
Host: example.com
Accept: application/yang.data+json
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The server might respond:
HTTP/1.1 200 OK
Date: Mon, 23 Apr 2012 17:11:30 GMT
Server: example-server
Cache-Control: no-cache
Pragma: no-cache
Content-Type: application/yang.data+json
{
"example-jukebox:jukebox" : {
"library" : {
"artist" : [ null ]
},
"playlist" : [
{
"name" : "Foo-One",
"description" : "example playlist 1",
"song" : [ null ]
}
],
"player" : {
"gap" : 0.5
}
}
}
D.3.3. "filter" Parameter
The following URIs show some examples of notification filter
specifications (lines wrapped for display purposes only):
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// filter = /event/eventClass='fault'
GET /restconf/streams/stream/NETCONF/events?
filter=%2Fevent%2FeventClass%3D'fault'
// filter = /event/severityCode<=4
GET /restconf/streams/stream/NETCONF/events?
filter=%2Fevent%2FseverityCode%3C%3D4
// filter = /linkUp|/linkDown
GET /restconf/streams/stream/SNMP/events?
filter=%2FlinkUp%7C%2FlinkDown
// filter = /*/reportingEntity/card!='Ethernet0'
GET /restconf/streams/stream/NETCONF/events?
filter=%2F*%2FreportingEntity%2Fcard%21%3D'Ethernet0'
// filter = /*/email-addr[contains(.,'company.com')]
GET /restconf/streams/stream/critical-syslog/events?
filter=%2F*%2Femail-addr[contains(.%2C'company.com')]
// Note: the module name is used as prefix.
// filter = (/example-mod:event1/name='joe' and
// /example-mod:event1/status='online')
GET /restconf/streams/stream/NETCONF/events?
filter=(%2Fexample-mod%3Aevent1%2Fname%3D'joe'%20and
%20%2Fexample-mod%3Aevent1%2Fstatus%3D'online')
D.3.4. "insert" Parameter
In this example, a new first entry in the "Foo-One" playlist is being
created.
Request from client:
POST /restconf/data/example-jukebox:jukebox/
playlist/Foo-One?insert=first HTTP/1.1
Host: example.com
Content-Type: application/yang.data+json
{
"example-jukebox:song" : {
"index" : 1,
"id" : "/example-jukebox:jukebox/library/artist/
Foo%20Fighters/album/Wasting%20Light/song/Rope"
}
}
Response from server:
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HTTP/1.1 201 Created
Date: Mon, 23 Apr 2012 13:01:20 GMT
Server: example-server
Last-Modified: Mon, 23 Apr 2012 13:01:20 GMT
Location: http://example.com/restconf/data/
example-jukebox:jukebox/playlist/Foo-One/song/1
ETag: eeeada438af
D.3.5. "point" Parameter
Example:
In this example, the client is inserting a new "song" resource within
an "album" resource after another song. The request URI is split for
display purposes only.
Request from client:
POST /restconf/data/example-jukebox:jukebox/
library/artist/Foo%20Fighters/album/Wasting%20Light?
insert=after&point=%2Fexample-jukebox%3Ajukebox%2F
library%2Fartist%2FFoo%20Fighters%2Falbum%2F
Wasting%20Light%2Fsong%2FBridge%20Burning HTTP/1.1
Host: example.com
Content-Type: application/yang.data+json
{
"example-jukebox:song" : {
"name" : "Rope",
"location" : "/media/foo/a7/rope.mp3",
"format" : "MP3",
"length" : 259
}
}
Response from server:
HTTP/1.1 204 No Content
Date: Mon, 23 Apr 2012 13:01:20 GMT
Server: example-server
Last-Modified: Mon, 23 Apr 2012 13:01:20 GMT
ETag: abcada438af
D.3.6. "select" Parameter
TBD
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D.3.7. "start-time" Parameter
TBD
D.3.8. "stop-time" Parameter
TBD
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Authors' Addresses
Andy Bierman
YumaWorks
Email: andy@yumaworks.com
Martin Bjorklund
Tail-f Systems
Email: mbj@tail-f.com
Kent Watsen
Juniper Networks
Email: kwatsen@juniper.net
Rex Fernando
Cisco
Email: rex@cisco.com
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