Margay - Websocket API Gateway

This service transform websocket messages to pub/sub communication via RMQ.

Our gateway - Margay like a small wild cat, consume minimum resources but provide flexible and scalable solution.

Architecture

Logical view

Physical view

Local stand

1. Run RMQ bitnami image used in example: docker compose up -d
2. Setup transport dsn via env MARGAY_TRANSPORT_DSN
3. Run application go run main.go
4. Login to RMQ dashboard via http://127.0.0.1:15672/
   • user: user
   • password: bitnami

Protocol

WSS connection

First request mast have Autorization header with JWT that represent user id

Example:

Autorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwidXNlciI6IkpvaG4gU25vdyIsImlhdCI6MTUxNjIzOTAyMn0.UrZ7NLiOUVVUerPuKouyr7NQz8XNb3jMrS_m0_07o8A

Token Decoded:

• Header:

 {
 "alg": "HS256",
 "typ": "JWT"
 }

• Claims: https://www.rfc-editor.org/rfc/rfc7519#section-4.1

 {
 "aud": "localhost", 
 "exp": "1.675816912e+09",
 "iat": "1.675730512e+09",
 "iss": "IdentityServiceLocal",
 "jti": "Jhohn Snow",
 "sub": "client"
 }

Limitation: for now only one connection allowed for 1 user.

Auth

Auth module is under definition. But main concept is to perform auth request to the Identity Provider and get cleintId from the token

Outbox

In RMQ transport represented as topic exchange by default name is MargayGatewayOutbox

RMQ Messages

On Client Connected

• Exchange: MargayGatewayOutbox
• Routing Key: ``
• Properties
  • headers:
    • recipient: *
    • sender: MargayGateway
  • Payload

  {
     "meta":{
        "object_id":"TestClient",
        "object_type":"client",
        "publisher":"MargayGateway",
        "event":"connected",
        "created":"2023-02-06T20:51:49+02:00"
     },
     "data":{
        
     }
  }

On Client Disconnected

• Exchange: MargayGatewayOutbox
• Routing Key: ``
• Properties
  • headers:
    • recipient: *
    • sender: MargayGateway
  • Payload

  {
     "meta":{
        "object_id":"TestClient",
        "object_type":"client",
        "publisher":"MargayGateway",
        "event":"disconnected",
        "created":"2023-02-06T20:51:49+02:00"
     },
     "data":{
        
     }
  }

Inbox

In RMQ transport represented as direct exchange by default name is MargayGatewayInbox Require that message headers to be set like:

• headers:
  • recipient: ClientId
  • sender: MyAwesomeMss
• Payload:
  • Accept serialized aka json,yaml and plain text messages.