kbavi / notifications-system

Service for notifications

Notifications Service

Requirements

• The system allows firing notifications to a particular user from anywhere in the codebase.
• The notifications contain a title, description, and an optional identifier to categorize them.
• The system will store the notifications in mongodb for future retrieval.
• Additionally, the system should has a WebSocket endpoint where the user can receive real-time notifications.
• The system will also have a feature to mark notifications as read.

Expected Behaviour and Use cases

• When a user receives a message from another user, the system fires a notification with the title "New Message Received" and the message's content as the description. The notification should have an identifier MESSAGE to categorize it.
• When a user is close to the end of their subscription period, the system should fire a notification with the title "Subscription Expiring Soon" and the description containing the expiration date. The notification should have an identifier SUBSCRIPTION_EXPIRY to categorize it.
• When a user completes their profile setup, the system should fire a notification with the title Profile Setup Complete and a description congratulating the user. The notification should have an identifier PROFILE_SETUP to categorize it.
• The functionality for generating events that trigger notifications, such as sending messages or completing user profiles, is mocked and not implemented in this project.

Installation

Prerequisites

1. docker
2. docker-compose

Installation Steps

1. git clone https://github.com/avinashb98/notifications-system
2. cd notifications-system
3. docker-compose build
4. docker-compose -f docker-compose.yml up

Testing

REST API

Head over to swagger api docs. The same doc can be used to interact with the implemented rest apis.

Websocket

A websocket client like Postman is required to interact with the websocket server of the app.

1. connect to the endpoint localhost:8000/ws/v1/notifications/{user_id}.
2. Pick one user out of the seed user ids (alex, bob, carol, dan) inorder to receive real-time notifications, e.g. localhost:8000/ws/v1/notifications/alex.

Folder Structure and Details

/api
    /routers
        notification.py             # notifications router

/config
    vars.py                         # app variables and settings

/database
    mongo.py                        # connects to mongodb

/entities
    enums.py                        # notification property enums
    notification.py                 # notification types, dto

/repositories
    /notification
        /base
            repository.py           # interface for crud over a datasource
    
        mongo_repository.py         # mongodb implementation of interface

/services
    /notification
        /base
            service.py              # interface for notification service over a repository
        v1.py                       # implementation of notification service
    
    /notifier
        notifier.py                 # sends notification to a user over websocket
    
    /ws
        manager.py                  # maintains users' websocket connections in the app

/simulator
    seed.py                         # generates random notifications from a fixed dataset