System design for Google Meet system

Designing a system like Google Meet involves creating a real-time video conferencing platform that supports multi-party video calls, screen sharing, and collaborative features. Here's a detailed system design using Prisma for database modeling, Express.js for API routes, and a recommended tech stack:

Tech Stack

• Backend: Node.js with Express.js
• Database: PostgreSQL for relational data (users, meetings, messages), Redis for caching
• ORM: Prisma for database interactions
• Real-time Communication: WebRTC for real-time audio and video communication
• Authentication: JWT (JSON Web Tokens) for user authentication and authorization
• WebSocket: Socket.io for signaling and real-time updates
• Storage: Amazon S3 for storing chat messages and media files
• Monitoring: Prometheus and Grafana for monitoring system metrics

System Components

1. Client Applications (Web and Mobile):

   • Interfaces for users to create meetings, join calls, share screens, chat, and manage settings.

2. Express.js Backend

   • Prisma Models:

     // schema.prisma
     
     datasource db {
       provider = "postgresql"
       url      = env("DATABASE_URL")
     }
     
     generator client {
       provider = "prisma-client-js"
     }
     
     model User {
       id          Int      @id @default(autoincrement())
       username    String   @unique
       email       String   @unique
       password    String
       meetings    Meeting[]
       createdAt   DateTime @default(now())
     }
     
     model Meeting {
       id            Int       @id @default(autoincrement())
       title         String
       startTime     DateTime
       endTime       DateTime
       organizerId   Int
       organizer     User      @relation(fields: [organizerId], references: [id])
       participants  User[]    @relation("Participants", references: [id])
       messages      Message[]
       createdAt     DateTime  @default(now())
     }
     
     model Message {
       id          Int      @id @default(autoincrement())
       content     String
       senderId    Int
       sender      User     @relation(fields: [senderId], references: [id])
       meetingId   Int
       meeting     Meeting  @relation(fields: [meetingId], references: [id])
       createdAt   DateTime @default(now())
     }
     

   • Express API Routes:

     // server.js
     
     const express = require('express');
     const http = require('http');
     const { Server } = require('socket.io');
     const { PrismaClient } = require('@prisma/client');
     const prisma = new PrismaClient();
     const jwt = require('jsonwebtoken');
     const bcrypt = require('bcrypt');
     const { v4: uuidv4 } = require('uuid');
     
     const app = express();
     const server = http.createServer(app);
     const io = new Server(server);
     
     app.use(express.json());
     
     // Socket.io middleware for authentication
     io.use((socket, next) => {
       const token = socket.handshake.auth.token;
       try {
         const decoded = jwt.verify(token, 'secret');
         socket.userId = decoded.userId;
         next();
       } catch (error) {
         return next(new Error('Authentication error'));
       }
     });
     
     // Endpoint for user registration
     app.post('/register', async (req, res) => {
       const { username, email, password } = req.body;
       try {
         const hashedPassword = await bcrypt.hash(password, 10);
         const user = await prisma.user.create({
           data: {
             username,
             email,
             password: hashedPassword,
           },
         });
         res.json(user);
       } catch (error) {
         console.error(error);
         res.status(500).json({ error: 'Failed to register user' });
       }
     });
     
     // Endpoint for user login and JWT generation
     app.post('/login', async (req, res) => {
       const { username, password } = req.body;
       try {
         const user = await prisma.user.findUnique({ where: { username } });
         if (!user) {
           return res.status(404).json({ error: 'User not found' });
         }
         const passwordMatch = await bcrypt.compare(password, user.password);
         if (!passwordMatch) {
           return res.status(401).json({ error: 'Invalid password' });
         }
         const token = jwt.sign({ userId: user.id }, 'secret', { expiresIn: '1h' });
         res.json({ token });
       } catch (error) {
         console.error(error);
         res.status(500).json({ error: 'Login failed' });
       }
     });
     
     // Endpoint for creating a new meeting
     app.post('/meetings', async (req, res) => {
       const { title, startTime, endTime } = req.body;
       try {
         const user = await prisma.user.findUnique({ where: { id: req.userId } });
         if (!user) {
           return res.status(404).json({ error: 'User not found' });
         }
         const meeting = await prisma.meeting.create({
           data: {
             title,
             startTime,
             endTime,
             organizerId: user.id,
             participants: { connect: { id: user.id } },
             messages: {
               create: {
                 content: `${user.username} created the meeting`,
                 senderId: user.id,
               },
             },
           },
         });
         res.json(meeting);
       } catch (error) {
         console.error(error);
         res.status(500).json({ error: 'Failed to create meeting' });
       }
     });
     
     // WebSocket event handling for real-time communication
     io.on('connection', (socket) => {
       console.log(`User ${socket.userId} connected`);
       socket.on('send-message', async ({ meetingId, content }) => {
         try {
           const user = await prisma.user.findUnique({ where: { id: socket.userId } });
           if (!user) {
             throw new Error('User not found');
           }
           const message = await prisma.message.create({
             data: {
               content,
               senderId: socket.userId,
               meetingId,
             },
           });
           socket.broadcast.emit('receive-message', { meetingId, message });
         } catch (error) {
           console.error('Error sending message:', error);
         }
       });
     
       socket.on('disconnect', () => {
         console.log(`User ${socket.userId} disconnected`);
       });
     });
     
     const PORT = process.env.PORT || 3000;
     server.listen(PORT, () => {
       console.log(`Server is running on http://localhost:${PORT}`);
     });
     

3. Database Layer

   • PostgreSQL: Stores user data, meeting details, chat messages, and transactional information.
   • Redis: Used for caching user sessions and improving performance of real-time communication.

4. Real-time Communication

   • WebRTC: Enables real-time audio and video communication between participants in meetings, with peer-to-peer data channels.

5. Authentication and Authorization

   • JWT: Token-based authentication for securing API endpoints and managing user sessions securely.

6. Messaging

   • RabbitMQ: Used for handling asynchronous tasks such as sending notifications, managing meeting schedules, and updating participant lists.

7. Storage

   • Amazon S3: Stores chat messages, media files (images, documents), and meeting recordings securely, with scalable storage and retrieval capabilities.

8. Monitoring and Analytics

   • Prometheus and Grafana: Monitor system metrics, track performance, and troubleshoot issues proactively.

Why This Tech Stack?

• Node.js with Express.js: Efficient for handling asynchronous I/O operations, building scalable APIs, and integrating with WebSocket for real-time communication.
• Prisma: Simplifies database interactions with type-safe queries and migrations, ensuring data integrity and reliability.
• WebRTC: Provides low-latency, high-quality audio and video streaming, essential for real-time meetings and collaboration.
• PostgreSQL: Offers relational data storage, ACID compliance, and support for complex queries required for managing meetings and user interactions.
• Redis: Improves performance with caching of user sessions and real-time data updates.
• Amazon S3: Secure and scalable storage solution for storing media files, chat messages, and meeting recordings.
• RabbitMQ: Ensures reliable messaging and event-driven architecture for handling asynchronous tasks and notifications.

Scalability and Fault Tolerance

• Horizontal Scaling: Deploy multiple instances of microservices and use load balancing to handle high traffic and ensure availability.
• Database Sharding: Partition databases to distribute load and scale horizontally as the number of users and meetings increase.
• Redundancy and Backup: Store backups in Amazon S3 and deploy services across multiple availability zones (AZs) for fault tolerance and disaster recovery.