RESTCONF Extension to support Trace Context Headers

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Table of Contents

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.¶

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.¶

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].¶

  error-tag:      operation-failed
  error-type:     protocol
  error-severity: error

  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"
      }
    ]
  }

 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"
         }
       }
     ]
   }
 }

3. Security Considerations

TODO Security¶

4. IANA Considerations

This document has no IANA actions.¶

5. Acknowledgments

We would like to acknowledge¶

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