rtyler/otto
rtyler
/
otto
1
1
Fork 0
Code Issues Pull Requests Releases Activity
otto/rfc/0010-eventbus.adoc

6.3 KiB
Raw Permalink Blame History

<html lang="en"> <head> </head>

RFC-0010: Eventbus design and implementation

Table 1. Metadata

RFC

0010

Title

Eventbus design and implementation

Sponsor

R Tyler Croy

Status

Not Submitted ℹ️

Type

Standard

Created

2020-06-20
Table of Contents

Abstract

THe eventbus is the core of the Otto ecosystem, which provides stateless pubsub channels and stateful queues over WebSocket connections.

Other services in the Otto ecosystem are expected to register for events by subscribing to different channels. Events from these channels will be received over a single WebSocket connection.

Specification

Tip

Provide a detailed specification what is being proposed. Be as technical and detailed as needed to allow new or existing developers to reasonably understand the scope/impact of an implementation.

  • Use present tense - describe what the proposal "does" (as if it were already done) not what it will do.

  • Do not discuss alternative designs that were rejected, those belong in the Reasoning section.

  • Avoid in-depth discussion or justification of design choices, that belongs in the Reasoning section.

Events

Register

The register message is required in order to identify the client with the eventbus for all future communications. The register event will also ensure that an "inbox" is created for the sending client, allowing it to receive unicasted messages.

{
  "type" : "register",
  "value" : {
    "uuid" : "some-uuid-string", // (1)
    "token" : "optional-auth-token" // (2)
  }
}

  1. The UUID should be the client’s own identifier which is guaranteed to be identical between restarts

  2. The token is optional for first-time clients, but required for reconnecting clients to resume their previous identifier

Responses
Success
{
    "type" : "registered",
    "value" : {
        "token" : "client's auth token" // (1)
    }
}

  1. The client’s secret authentication token to use in the future

Errors:

  • Invalid auth token for identifier

  • Client already registered

Subscribe

{
  "type" : "subscribe",
  "value" : {
    "client" : {
        "uuid" : "client-uuid",
        "token" : "auth-token"
    },
    "channel" :  "/channel/identifier"
  }
}
Responses
Success
{
    "type" : "subscribed",
    "value" : {
        "client" : "client-uuid",
        "channel": "/channel/identifier"
    }
}
Error
{
    "type" : "error",
    "value" : {
        "code" : 10,  // (1)
        "msg" : "errors.subscription_failed" // (2)
    }
}

  1. A predefined error code matching the message

  2. A string denoting which type of error message should be shown to the user

Motivation

Tip

Explain why the existing code base or process is inadequate to address the problem that the RFC solves. This section may also contain any historal context such as how things were done before this proposal.

  • Do not discuss design choices or alternative designs that were rejected, those belong in the Reasoning section.

Reasoning

Tip

Explain why particular design decisions were made. Describe alternate designs that were considered and related work, e.g. how the feature is supported in other systems. Provide evidence of consensus within the community and discuss important objections or concerns raised during discussion.

  • Use sub-headings to organize this section for ease of readability.

  • Do not talk about history or why this needs to be done, that is part of Motivation section.

Backwards Compatibility

Tip

Describe any incompatibilities and their severity. Describe how the RFC proposes to deal with these incompatibilities.

If there are no backwards compatibility concerns, this section may simply say: There are no backwards compatibility concerns related to this proposal.

Security

Tip

Describe the security impact of this proposal. Outline what was done to identify and evaluate security issues, discuss of potential security issues and how they are mitigated or prevented, and how the RFC interacts with existing permissions, authentication, authorization, etc.

If this proposal will have no impact on security, this section may simply say: There are no security risks related to this proposal.

Testing

Tip

If the RFC involves any kind of behavioral change to code give a summary of how its correctness (and, if applicable, compatibility, security, etc.) can be tested.

In the preferred case that automated tests can be developed to cover all significant changes, simply give a short summary of the nature of these tests.

If some or all of changes will require human interaction to verify, explain why automated tests are considered impractical. Then summarize what kinds of test cases might be required: user scenarios with action steps and expected outcomes. Might behavior vary by platform (operating system, servlet container, web browser, etc.)? Are there foreseeable interactions between different permissible versions of components? Are any special tools, proprietary software, or online service accounts required to exercise a related code path (Active Directory server, GitHub login, etc.)? When will testing take place relative to merging code changes, and might retesting be required if other changes are made to this area in the future?

If this proposal requires no testing, this section may simply say: There are no testing issues related to this proposal.

Prototype Implementation

Tip

Link to any open source reference implementation of code changes for this proposal. The implementation need not be completed before the RFC is accepted but must be completed before the RFC is given "final" status.

RFCs which will not include code changes may omit this section.

References

Tip

Provide links to any related documents. This will include links to discussions on the mailing list, pull requests, and meeting notes.
Last updated 2024-05-15 15:46:50 UTC
</html>