XEP-0455: Service Outage Status

Abstract
This document defines an XMPP protocol extension that enables server administrators to communicate issues with the server to all users in a semantic manner.
Author
Mathieu Pasquet
Copyright
© 1999 – 2021 XMPP Standards Foundation. SEE LEGAL NOTICES.
Status

Experimental

WARNING: This Standards-Track document is Experimental. Publication as an XMPP Extension Protocol does not imply approval of this proposal by the XMPP Standards Foundation. Implementation of the protocol described herein is encouraged in exploratory implementations, but production systems are advised to carefully consider whether it is appropriate to deploy implementations of this protocol before it advances to a status of Draft.
Type
Standards Track
Version
0.2.0 (2021-02-09)
Document Lifecycle
  1. Experimental
  2. Proposed
  3. Stable
  4. Final

1. Introduction

The XMPP Network is a network of servers which each have their own administration policies, status reports, and other peculiarities. Contact Addresses for XMPP Services (XEP-0157) [1] provides a consistent framework for reaching out to administrators and reporting abuse, incidents, or even giving feedback on the service, and the goal of this specification is to provide a similar framework for letting users (or other entities) know the server status in-band or out of band (in case of hard failures).

Centralized systems usually control both the infrastructure and client code, making it easy to hardcode information retrieval one way or the other.

The usual way of informing users of planned maintenance, partial or total outage was previously through "announce" modules that lets the admin broadcast server-wided messages. This approach has several drawbacks, as it will appear in most clients as a new discussion with the server JID, which can prove confusing. It also does not provide a way to reach the user when the XMPP server is offline.

This XEP provides:

2. External status

2.1 Discovery

To make such discovery possible, we specify a Service Discovery Extensions (XEP-0128) [2] mechanism that a server SHOULD return in response to service discovery information ("disco#info") requests sent to the bare domain of the server. This information MUST be scoped using a FORM_TYPE of "urn:xmpp:sos:0" (as already specified in XEP-0128) and data form fields registered for this purpose as defined in the XMPP Registrar Considerations section of this document.

Values of 'external-status-addresses' form field MUST be valid URIs, i.e. comply with the 'xs:anyURI' datatype of XML Schema Part 2 [4].

Example 1. Entity queries server for information
<iq from='thirdwitch@shakespeare.lit/chamber'
    to='shakespeare.lit'
    id='disco1'
    type='get'>
  <query xmlns='http://jabber.org/protocol/disco#info'/>
</iq>
Example 2. Server communicates information
<iq from='shakespeare.lit'
    to='thirdwitch@shakespeare.list/chamber'
    id='disco1'
    type='result'>
  <query xmlns='http://jabber.org/protocol/disco#info'>
    <identity category='server' type='im'/>
    <feature var='http://jabber.org/protocol/disco'/>
    <x xmlns='jabber:x:data' type='result'>
      <field var='FORM_TYPE' type='hidden'>
        <value>urn:xmpp:sos:0</value>
      </field>
      <field var='external-status-addresses'>
        <value>http://secondary.shakespeare.lit/status.json</value>
      </field>
    </x>
  </query>
</iq>

Links present inside the 'external-status-addresses' field SHOULD use HTTP/HTTPS protocol and the resources referenced MUST be available without authentication.

2.2 External status format

TODO: do we want this to be XML or json? I have no real preference, in any case it should be preferably generated by a tool but easy to write by hand, as this needs to be usable in situations where time is the essence.

The format used for the external status is defined here, to allow a wide range of compatibility across services and clients.

A client MUST ignore unknown extra fields present in the JSON file, to allow extensibility, and implementations MAY add other fields.

Example 3. Example status
{
  "outage": "complete",
  "planned": true,
  "beginning": "2021-01-12T01:01:01Z",
  "expected_end": "2021-01-12T05:00:00Z",
  "message": {
    "default": "Mise à jour du serveur",
    "en": "The serveur is being updated"
  }
}
  

The "message" field MUST contain at least a message on the "default" key, that will be used by the client if the current user language is not found. It is left to the operator to determine which language is more relevant as a default, according to the server’s user base.

When the outage is over, the file SHOULD be replaced with an empty JSON object.

Example 4. Empty file after resolution of the issue
{}

The following JSON schema is provided as a means to describe and validate the file exposed by the external service:

{
  "$id": "http://xmpp.org/server-outage-schema.json",
  "$schema": "http://json-schema.org/draft-07/schema#",
  "title": "XMPP Server Outage Format",
  "type": "object",
  "required": ["beginning"],
  "additionalProperties": true,
  "properties": {
    "outage": {
      "type": "string",
      "enum": ["partial", "complete"],
      "description": "The outage status (partial or complete)."
    },
    "planned": {
      "type": "boolean",
      "description": "If the outage was planned or not."
    },
    "beginning": {
      "type": "string",
      "format": "date-time",
      "description": "Approximate time of the start of the outage."
    },
    "expected_end": {
      "type": "string",
      "format": "date-time",
      "description": "Estimated time of the end of the outage (if known)."
    },
    "message": {
    "type": "object",
      "description": "Textual message to service users, each key being 'defaul' or a BCP47 language tag.",
      "required": ["default"],
      "properties": {
        "default": { "type": "string"}
      },
      "patternProperties": {
        "default": {"type": "string"},
        ".*": {"type": "string"}
      }
    }
  }
}

3. In-band status

3.1 PubSub Node

For in-band notifications of server issues, a service with this extension SHOULD expose a 'urn:xmpp:sos:0' pubsub node with the acess model defined in Best Practices for Persistent Storage of Public Data via Publish-Subscribe (XEP-0222) [5] on its bare JID. This pubsub node contains items describing outages and outage resolutions, and each item MUST have an 'id' attribute value containing the outage date and time, in XMPP Date and Time Profiles (XEP-0082) [6] format.

Clients implementing this extension SHOULD subscribe to the '+notify' on that node, as defined in Publish-Subscribe (XEP-0060) [3].

Entities from other servers MAY be allowed to subscribe to other server nodes, to allow external services to monitor the server. Doing so allows aggregation of XMPP outage events across the network, for a better transparency.

3.2 Outage event

Example 5. Server operator publishes an outage event
  <iq from='firstwitch@shakespeare.lit/broom' to='shakespeare.lit' type='set' id='pub1'>
  <pubsub xmlns='http://jabber.org/protocol/pubsub'>
    <publish node='urn:xmpp:sos:0'>
      <item id="2021-01-01T01:01:01Z">
        <outage xmlns='urn:xmpp:sos:0'>
          <description xml:lang='en'>The ICQ and MSN gateways are down</description>
          <description xml:lang='fr'>Les passerelles ICQ et MSN sont mortes</description>
          <planned>false</planned>
          <expected_end>2021-01-01T05:00:00Z</expected_end>
        </outage>
      </item>
    </publish>
  </pubsub>
</iq>
Example 6. Client subscribed receives an outage event
<message from='shakespeare.lit'
         to='macbeth@shakespeare.lit/throne'
         type='headline'
         id='outagefoo'>
  <event xmlns='http://jabber.org/protocol/pubsub#event'>
    <items node='urn:xmpp:sos:0'>
      <item id="2021-01-01T01:01:01Z">
        <outage xmlns='urn:xmpp:sos:0'>
          <description xml:lang='en'>The ICQ and MSN gateways are down</description>
          <description xml:lang='fr'>Les passerelles ICQ et MSN sont mortes</description>
          <planned>false</planned>
          <expected_end>2021-01-01T05:00:00Z</expected_end>
        </outage>
      </item>
    </items>
  </event>
</message>

3.3 Outage End Event

When the outage is over, servers operators SHOULD publish an <outage-end/> element with the item id matching the time at which the issue was resolved. It can optionally contain a description.

Example 7. Server operator publishes an end of outage event
  <iq from='firstwitch@shakespeare.lit/broom' to='shakespeare.lit' type='set' id='pub2'>
  <pubsub xmlns='http://jabber.org/protocol/pubsub'>
    <publish node='urn:xmpp:sos:0'>
      <item id="2021-01-01T02:05:01Z">
        <outage-end xmlns='urn:xmpp:sos:0'>
          <description xml:lang="en">Everything has been fixed!</description>
          <description xml:lang="fr">Tout a été corrigé !</description>
        </outage-end>
      </item>
    </publish>
  </pubsub>
</iq>

Clients receiving this notification SHOULD remove the information about the outage from the user’s view, and MAY display the new message briefly.

4. Use Cases

This extension has been thought for several different cases of service outages:

5. Business Rules

A client implementing this extension MUST fetch the addresses of the external service and cache it for later use. Doing so allows the client to use this information when it is impossible to connect to the server.

A client receiving an outage event for a time in the future SHOULD treat it as a planned event that is not already happening and adapt its display consequently.

When connected, a client SHOULD NOT fetch the external file as the in-band notification provides the same information, if available.

6. Internationalization Considerations

Both the JSON and the XML format defined in this document allow for internationalization in the fields that are expected to be presented to the user as-is. The other fields are machine-readable and their various values SHOULD be translated in the implementing applications.

7. Security Considerations

Client implementations MUST check the provenance of the pubsub notifications before displaying a notification, otherwise malicious entities could send fake outage events.

Server administrators MUST ensure the servers provided in 'external-status-addresses' are trusted, as malicious administrators of this server could use the referenced file to display arbitrary messages to users.

8. IANA Considerations

This document requires no interaction with the Internet Assigned Numbers Authority (IANA) [7].

9. XMPP Registrar Considerations

The XMPP Registrar [8] includes the following information in its registries.

9.1 Field Standardization

Field Standardization for Data Forms (XEP-0068) [9] defines a process for standardizing the fields used within Data Forms qualified by a particular namespace, and XEP-0128 describes how to use field standardization in the context of service discovery. This section registers fields for server information scoped by the "urn:xmpp:sos:0" FORM_TYPE.

Registry Submission
<form_type>
  <name>urn:xmpp:sos:0</name>
  <doc>XEP-XXXXX</doc>
  <desc>
    Form enabling a the registration of a machine-readable
    external file to describe a service status.
  </desc>
  <field
      var='external-status-addresses'
      type='list-multi'
      label='One or more addresses containing a file with the server status'/>
</form_type>

10. XML Schema

REQUIRED for protocol specifications.


Appendices

Appendix A: Document Information

Series
XEP
Number
0455
Publisher
XMPP Standards Foundation
Status
Experimental
Type
Standards Track
Version
0.2.0
Last Updated
2021-02-09
Approving Body
XMPP Council
Dependencies
XMPP Core, XEP-0060, XEP-0128, XEP-0222
Supersedes
None
Superseded By
None
Short Name
NOT_YET_ASSIGNED
Source Control
HTML

This document in other formats: XML  PDF

Appendix B: Author Information

Mathieu Pasquet
Email
mathieui@mathieui.net
JabberID
mathieui@mathieui.net

Copyright

This XMPP Extension Protocol is copyright © 1999 – 2020 by the XMPP Standards Foundation (XSF).

Permissions

Permission is hereby granted, free of charge, to any person obtaining a copy of this specification (the "Specification"), to make use of the Specification without restriction, including without limitation the rights to implement the Specification in a software program, deploy the Specification in a network service, and copy, modify, merge, publish, translate, distribute, sublicense, or sell copies of the Specification, and to permit persons to whom the Specification is furnished to do so, subject to the condition that the foregoing copyright notice and this permission notice shall be included in all copies or substantial portions of the Specification. Unless separate permission is granted, modified works that are redistributed shall not contain misleading information regarding the authors, title, number, or publisher of the Specification, and shall not claim endorsement of the modified works by the authors, any organization or project to which the authors belong, or the XMPP Standards Foundation.

Disclaimer of Warranty

## NOTE WELL: This Specification is provided on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, express or implied, including, without limitation, any warranties or conditions of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A PARTICULAR PURPOSE. ##

Limitation of Liability

In no event and under no legal theory, whether in tort (including negligence), contract, or otherwise, unless required by applicable law (such as deliberate and grossly negligent acts) or agreed to in writing, shall the XMPP Standards Foundation or any author of this Specification be liable for damages, including any direct, indirect, special, incidental, or consequential damages of any character arising from, out of, or in connection with the Specification or the implementation, deployment, or other use of the Specification (including but not limited to damages for loss of goodwill, work stoppage, computer failure or malfunction, or any and all other commercial damages or losses), even if the XMPP Standards Foundation or such author has been advised of the possibility of such damages.

IPR Conformance

This XMPP Extension Protocol has been contributed in full conformance with the XSF's Intellectual Property Rights Policy (a copy of which can be found at <https://xmpp.org/about/xsf/ipr-policy> or obtained by writing to XMPP Standards Foundation, P.O. Box 787, Parker, CO 80134 USA).

Visual Presentation

The HTML representation (you are looking at) is maintained by the XSF. It is based on the YAML CSS Framework, which is licensed under the terms of the CC-BY-SA 2.0 license.

Appendix D: Relation to XMPP

The Extensible Messaging and Presence Protocol (XMPP) is defined in the XMPP Core (RFC 6120) and XMPP IM (RFC 6121) specifications contributed by the XMPP Standards Foundation to the Internet Standards Process, which is managed by the Internet Engineering Task Force in accordance with RFC 2026. Any protocol defined in this document has been developed outside the Internet Standards Process and is to be understood as an extension to XMPP rather than as an evolution, development, or modification of XMPP itself.

Appendix E: Discussion Venue

The primary venue for discussion of XMPP Extension Protocols is the <standards@xmpp.org> discussion list.

Discussion on other xmpp.org discussion lists might also be appropriate; see <https://xmpp.org/about/discuss.shtml> for a complete list.

Errata can be sent to <editor@xmpp.org>.

Appendix F: Requirements Conformance

The following requirements keywords as used in this document are to be interpreted as described in RFC 2119: "MUST", "SHALL", "REQUIRED"; "MUST NOT", "SHALL NOT"; "SHOULD", "RECOMMENDED"; "SHOULD NOT", "NOT RECOMMENDED"; "MAY", "OPTIONAL".

Appendix G: Notes

1. XEP-0157: Contact Addresses for XMPP Services <https://xmpp.org/extensions/xep-0157.html>.

2. XEP-0128: Service Discovery Extensions <https://xmpp.org/extensions/xep-0128.html>.

3. XEP-0060: Publish-Subscribe <https://xmpp.org/extensions/xep-0060.html>.

4. XML Schema Part 2: Datatypes <http://www.w3.org/TR/xmlschema11-2/>.

5. XEP-0222: Best Practices for Persistent Storage of Public Data via Publish-Subscribe <https://xmpp.org/extensions/xep-0222.html>.

6. XEP-0082: XMPP Date and Time Profiles <https://xmpp.org/extensions/xep-0082.html>.

7. The Internet Assigned Numbers Authority (IANA) is the central coordinator for the assignment of unique parameter values for Internet protocols, such as port numbers and URI schemes. For further information, see <http://www.iana.org/>.

8. The XMPP Registrar maintains a list of reserved protocol namespaces as well as registries of parameters used in the context of XMPP extension protocols approved by the XMPP Standards Foundation. For further information, see <https://xmpp.org/registrar/>.

9. XEP-0068: Field Data Standardization for Data Forms <https://xmpp.org/extensions/xep-0068.html>.

Appendix H: Revision History

Note: Older versions of this specification might be available at https://xmpp.org/extensions/attic/

  1. Version 0.2.0 (2021-02-09)
    Evolve the standard: Editorial restructuring, add business rules and security considerations and clarify some wording.
  2. Version 0.1.0 (2021-02-09)
    Accepted by vote of Council on 2021-01-20.
    XEP Editor (jsc)
  3. Version 0.0.1 (2021-01-18)

    First draft.

    mp

Appendix I: Bib(La)TeX Entry

@report{pasquet2021xep0455,
  title = {Service Outage Status},
  author = {Pasquet, Mathieu},
  type = {XEP},
  number = {0455},
  version = {0.2.0},
  institution = {XMPP Standards Foundation},
  url = {https://xmpp.org/extensions/xep-0455.html},
  date = {2021-01-18/2021-02-09},
}

END