Network Working Group                                         C. Divilly
Internet-Draft                                        Oracle Corporation
Updates: 7231 (if approved)                                20 March 2020
Intended status: Informational
Expires: 21 September 2020


              User Defined Resource Error HTTP Status Code
                      draft-divilly-status-555-00

Abstract

   This document specifies an additional HyperText Transfer Protocol
   (HTTP) status code to indicate server error conditions arising during
   evaluation of user defined resources hosted by the server.

Conventions and Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 21 September 2020.

Copyright Notice

   Copyright (c) 2020 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights



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   and restrictions with respect to this document.  Code Components
   extracted from this document must include Simplified BSD License text
   as described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  555 User Defined Resource Error . . . . . . . . . . . . . . .   2
     2.1.  Relationship to 500 Internal Server Error . . . . . . . .   3
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   5.  Example . . . . . . . . . . . . . . . . . . . . . . . . . . .   4
   6.  Normative References  . . . . . . . . . . . . . . . . . . . .   5
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   Some HTTP servers offer mechanisms for users to define their own
   programmatically generated resources.  This specification terms such
   a resource as a 'User Defined Resource'.  In such cases it may be
   useful to distinguish between errors arising due to defects in the
   User Defined Resource and errors arising due to defects in the server
   itself.

   This document proposes a new HTTP status code.  This status code
   indicates that an error occurred when the server attempted to produce
   a representation of the User Defined Resource, and the error occurred
   when attempting to evaluate the program that generates the resource,
   rather than an error condition in the server itself.

2.  555 User Defined Resource Error

   The 555 (User Defined Resource Error) status code indicates that the
   server encountered an unexpected condition when evaluating a User
   Defined Resource that prevented the server from fulfilling the
   request.

   The response message MAY contain information that identifies the User
   Defined Resource that originated the error.  The response message
   SHOULD contain additional information that can help the author of
   User Defined Resource diagnose the root cause of the error.

   The response SHOULD include an identifier that uniquely identifies
   the error condition instance.  This identifier should also appear
   with any log messages or other diagnostic information that the server
   produces.




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   The response MAY include a URI [RFC3986] that points to a resource
   that the User Defined Resource author can use to review the log and
   other diagnostic information associated with the error condition.
   Access to this URI MUST be restricted to ensure only the User Defined
   Resource author can access it.

   It is RECOMMENDED that the server provide the User Defined Resource
   author with secured access to the logs pertaining to the error
   instance, and a capability to filter/search these logs keyed by the
   error identifier.

   The log information SHOULD provide detailed information about the
   nature and origin of the error, to enable the User Defined Resource
   author to diagnose the root cause of the error, whereas the error
   response SHOULD contain the minimal information required to identify
   the corresponding log messages.

2.1.  Relationship to 500 Internal Server Error

   The "555" status code can be considered a specialization of the "500"
   status code.  To quote the HTTP Specification
   (https://tools.ietf.org/html/rfc7231#section-6) [RFC7231]:

   |  HTTP status codes are extensible.  HTTP clients are not required
   |  to understand the meaning of all registered status codes, though
   |  such understanding is obviously desirable.  However, a client MUST
   |  understand the class of any status code, as indicated by the first
   |  digit, and treat an unrecognized status code as being equivalent
   |  to the x00 status code of that class

   Thus clients SHOULD treat the "555" status code in the same manner as
   they treat the "500" status code.

   The primary value of the "555" status code is to enable operators of
   a server to easily distinguish between error conditions arising due
   to problems in the server itself, and error conditions arising due to
   problems in a User Defined Resource.

   A 500 status is unexpected and likely requires a corrective action
   from the server operators, as the error may indicate a threat to the
   stability and availability of the server.

   A 555 status is likely to be commonplace, as User Defined Resource
   authors will be expected to make mistakes when authoring those
   resources.  Assuming a well architected server with proper isolation
   between the server and the User Defined Resources, such error
   conditions are unlikely to be a threat to the stability and
   availability of the server.



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   The ability to distinguish between 500 and 555 status codes provides
   similar value to User Defined Resource authors and end users of the
   User Defined Resource.

3.  IANA Considerations

   The HTTP Status Codes Registry (https://www.iana.org/assignments/
   http-status-codes/http-status-codes.xhtml) should be updated with the
   following entry:

   *  Code: 555

   *  Description: User Defined Resource Error

   *  Specification: [ this document ]

4.  Security Considerations

   When the server includes information that identifies the User Defined
   Resource that caused the error, or additional information that helps
   the author diagnose the root cause, care must be taken not to
   disclose information that may be useful to an attacker.

   Care needs to be taken to ensure that the log messages do not reveal
   sensitive information about the users of the User Defined Resource,
   see [RFC7230] section 9.8 (https://tools.ietf.org/html/
   rfc7230#section-9.8) for relevant guidance on this topic.

5.  Example

   This section is non-normative.

   Below is an example response that leverages the Problem Details for
   HTTP APIs (https://tools.ietf.org/html/rfc7807) syntax [RFC7807] to
   communicate information about the error condition:

   HTTP/1.1 555 User Defined Resource Error
   Content-Type: application/problem+json
   Content-Language: en

   {
    "type":     "https://example.com/errs/user-defined-resource-error",
    "title":    "User Defined Resource Error",
    "detail":   "An unexpected error condition occurred when
                 evaluating a user defined resource",
    "trace_id": "a75382c4-d61d-4c16-8dde-a01afc7b51a2",
    "instance": "/logs/?trace_id=a75382c4-d61d-4c16-8dde-a01afc7b51a2"
   }



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   *  The "detail" message is careful to reveal minimal information
      about the User Defined Resource that experienced the error
      condition.

   *  The "trace_id" field provides a unique identifier for the error
      condition that can be used to correlate corresponding log entries
      and other diagnostic information relevant to this error condition.

   *  The "instance" URI points to a (secured) resource that can be
      interrogated to view all the log messages associated with this
      specific error instance.

6.  Normative References

   [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>.

   [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
              Resource Identifier (URI): Generic Syntax", STD 66,
              RFC 3986, DOI 10.17487/RFC3986, January 2005,
              <https://www.rfc-editor.org/info/rfc3986>.

   [RFC7231]  Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
              Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
              DOI 10.17487/RFC7231, June 2014,
              <https://www.rfc-editor.org/info/rfc7231>.

   [RFC7230]  Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
              Protocol (HTTP/1.1): Message Syntax and Routing",
              RFC 7230, DOI 10.17487/RFC7230, June 2014,
              <https://www.rfc-editor.org/info/rfc7230>.

   [RFC7807]  Nottingham, M. and E. Wilde, "Problem Details for HTTP
              APIs", RFC 7807, DOI 10.17487/RFC7807, March 2016,
              <https://www.rfc-editor.org/info/rfc7807>.

Author's Address

   Colm Divilly
   Oracle Corporation

   Email: colm.divilly@oracle.com







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