Features

Applicative server

• Server uses Routers to process the messages in the queue
• A Router is subscribed to a NATS queue and will get all messages through it
• Use of protobuf messages to encapsulate NATS messages (see Messages example for further details)

NATS Clients

• Connected to the NATS server
• Use of Publish/Subscribe and Request/Reply message distribution model to interact with both the applicative server and other clients
• Some client examples :
  • Identified echo : Dialogue between an identified client and the applicative server
  • Caching echo : Dialogue between a client and a server, the message is cached for 5s
  • Ping Pong : Conversation between 2 clients
  • Sending files : Use of MinIO to send images and modify them in the applicative server

Authentication service

• Service uses JWT authentication
• API with two endpoints :
  • /register : Save user email and ID in database
  • /login : Create user credentials using the NSC Service
• Credentials are valid for 6 months by default (can be changed through NscSettings)
• Credentials define both the identity of the client thanks to its keys but also the authorization given (which queues can a client post and listen on)

NSC Service and Wrapper

• NSC Wrapper is a Python wrapper that calls the nsc library
  • Used to create NATS Operator, Account and User
• NSC Service is an API used to set up a new Operator and Account when creating a new system
• NSC Service is also called during user creation, this service effectively creates user private and public keys as well as their credentials

Persistent messaging

• NATS Jetstream is a service that allows server side persistence once enabled on the NATS server
• The Buffer allows for client side persistence by saving unsent messages in case of errors (see Persistence example for further details)
• Some client examples :
  • Stream echo : Dialogue between an identified client and the applicative server using all persistence features