Internet DRAFT - draft-rogaglia-netconf-restconf-trace-ctx-headers
draft-rogaglia-netconf-restconf-trace-ctx-headers
NETCONF R. Gagliano
Internet-Draft Cisco Systems
Intended status: Standards Track K. Larsson
Expires: 7 January 2024 Deutsche Telekom AG
J. Lindblad
Cisco Systems
6 July 2023
RESTCONF Extension to support Trace Context Headers
draft-rogaglia-netconf-restconf-trace-ctx-headers-00
Abstract
This document extends the RESTCONF protocol in order to support trace
context propagation as defined by the W3C.
About This Document
This note is to be removed before publishing as an RFC.
The latest revision of this draft can be found at TBD. Status
information for this document may be found at
https://datatracker.ietf.org/doc/draft-rogaglia-netconf-restconf-
trace-ctx-headers/.
Discussion of this document takes place on the NETCONF Working Group
mailing list (mailto:netconf@ietf.org), which is archived at
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Source for this draft and an issue tracker can be found at
https://github.com/TBD.
Status of This Memo
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on 7 January 2024.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. RESTCONF Extensions . . . . . . . . . . . . . . . . . . . . . 3
2.1. Errors handling . . . . . . . . . . . . . . . . . . . . . 3
2.2. Trace Context header versionning . . . . . . . . . . . . 5
3. Security Considerations . . . . . . . . . . . . . . . . . . . 5
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
5. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 5
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
6.1. Normative References . . . . . . . . . . . . . . . . . . 5
6.2. Informative References . . . . . . . . . . . . . . . . . 6
Appendix A. Example RESTCONF calls . . . . . . . . . . . . . . . 6
Appendix B. Changes (to be deleted by RFC Editor) . . . . . . . 6
Appendix C. TO DO List (to be deleted by RFC Editor) . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
Network automation and management systems commonly consist of
multiple sub-systems and together with the network devices they
manage, they effectively form a distributed system. Distributed
tracing is a methodology implemented by tracing tools to follow,
analyze and debug operations, such as configuration transactions,
across multiple distributed systems. An operation is uniquely
identified by a trace-id and through a trace context, carries some
metadata about the operation. Propagating this "trace context"
between systems enables forming a coherent view of the entire
operation as carried out by all involved systems.
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The W3C has defined two HTTP headers (traceparent and tracestate) for
context propagation that are useful for distributed systems like the
ones defined in [RFC8309]. The goal of this document is to adopt
this W3C specification for the RESTCONF protocol.
This document does not define new HTTP extensions but makes those
defined in [W3C-Trace-Context] optional headers for the RESTCONF
protocol.
In [I-D.draft-rogaglia-netconf-trace-ctx-extension-03], the NETCONF
protocol extension is defined and we will re-use several of the YANG
and XML objects defined in that document for RESTCONF. Please refer
to that document for additional context and example applications.
1.1. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
NOT","SHOULD","SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY",
and "OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
2. RESTCONF Extensions
A RESTCONF server SHOULD support trace context traceparent header as
defined in [W3C-Trace-Context].
A RESTCONF server SHOULD support trace context tracestate header as
defined in [W3C-Trace-Context].
2.1. Errors handling
The RESTCONF server SHOULD follow the "Processing Model for Working
with Trace Context" as specified in [W3C-Trace-Context].
If the server rejects the RPC because of the trace context headers
values, the server MUST return an rpc-error with the following
values:
error-tag: operation-failed
error-type: protocol
error-severity: error
Additionally, the error-info tag SHOULD contain a relevant details
about the error.
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Finally, the sx:structure defined in
[I-D.draft-rogaglia-netconf-trace-ctx-extension-03] SHOULD be present
in any error message from the server.
Example of a badly formated trace context extension using [RFC8040]
example B.2.1:
POST /restconf/data/example-jukebox:jukebox/library HTTP/1.1
Host: example.com
Content-Type: application/yang-data+json
traceparent: SomeBadFormatHere
tracestate: OrSomeBadFormatHere
{
"example-jukebox:artist" : [
{
"name" : "Foo Fighters"
}
]
}
And the expected error message:
HTTP/1.1 400 Bad Request
Date: Tue, 20 Jun 2023 20:56:30 GMT
Server: example-server
Content-Type: application/yang-data+json
{ "ietf-restconf:errors" : {
"error" : [
{
"error-type" : "protocol",
"error-tag" : "operation-failed",
"error-severity" : "error",
"error-message" :
"OTLP traceparent attribute incorrectly formatted",
"error-info": {
"ietf-netconf-otlp-context:meta-name" : "traceparent",
"ietf-netconf-otlp-context:meta-value" :
"SomeBadFormatHere",
"ietf-netconf-otlp-context:error-type" :
"ietf-netconf-otlp-context:bad-format"
}
}
]
}
}
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2.2. Trace Context header versionning
This extension refers to the [W3C-Trace-Context] trace context
capability. The W3C traceparent and trace-state headers include the
notion of versions. It would be desirable for a RESTCONF client to
be able to discover the one or multiple versions of these headers
supported by a server. We would like to achieve this goal avoiding
the deffinition of new RESTCONF capabilities for each headers'
version.
[I-D.draft-rogaglia-netconf-trace-ctx-extension-03] defines a pair
YANG modules that SHOULD be included in the YANG library per
[RFC8525] of the RESTCONF server supporting the RESTCONF Trace
Context extension that will refer to the headers' supported versions.
Future updates of this document could include additional YANG modules
for new headers' versions.
3. Security Considerations
TODO Security
4. IANA Considerations
This document has no IANA actions.
5. Acknowledgments
We would like to acknowledge
6. References
6.1. Normative References
[I-D.draft-rogaglia-netconf-trace-ctx-extension-03]
Gagliano, R., Larsson, K., and J. Lindblad, "NETCONF
Extension to support Trace Context propagation", Work in
Progress, Internet-Draft, draft-rogaglia-netconf-trace-
ctx-extension-03, 6 July 2023,
<https://datatracker.ietf.org/doc/html/draft-rogaglia-
netconf-trace-ctx-extension-03>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
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[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/info/rfc8040>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8525] Bierman, A., Bjorklund, M., Schoenwaelder, J., Watsen, K.,
and R. Wilton, "YANG Library", RFC 8525,
DOI 10.17487/RFC8525, March 2019,
<https://www.rfc-editor.org/info/rfc8525>.
[W3C-Trace-Context]
"W3C Recommendation on Trace Context", 23 November 2021,
<https://www.w3.org/TR/2021/REC-trace-context-
1-20211123/>.
6.2. Informative References
[RFC8309] Wu, Q., Liu, W., and A. Farrel, "Service Models
Explained", RFC 8309, DOI 10.17487/RFC8309, January 2018,
<https://www.rfc-editor.org/info/rfc8309>.
Appendix A. Example RESTCONF calls
TBD
Appendix B. Changes (to be deleted by RFC Editor)
Appendix C. TO DO List (to be deleted by RFC Editor)
* Security Considerations
* Example RESTCONF Calls
* The W3C is working on a draft document to introduce the concept of
"baggage" that we expect part of a future draft for NETCONF and
RESTCONF
Authors' Addresses
Roque Gagliano
Cisco Systems
Avenue des Uttins 5
CH-1180 Rolle
Switzerland
Email: rogaglia@cisco.com
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Kristian Larsson
Deutsche Telekom AG
Email: kll@dev.terastrm.net
Jan Lindblad
Cisco Systems
Email: jlindbla@cisco.com
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