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packages/loadbalancer/README.md

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+# Load Balancer for WebRTC Mediasoup Servers
+
+## 🚀 Overview
+
+This project implements a **load balancer** for WebRTC **Mediasoup** servers. It enables **automatic server registration**, **health monitoring**, and **dynamic load balancing** to efficiently distribute WebRTC rooms among the available servers, ensuring a scalable and robust architecture.
+
+---
+
+## ⚡ **Key Features**
+
+### **Server Registration**
+
+- **Dynamic server registration**: Servers register themselves dynamically when they start up.
+- **Duplicate prevention**: If a server is already registered, the previous entry is removed and updated.
+- **Capacity calculation**: Each server's **total capacity** is computed based on the number of workers (`workers × 500 consumers`).
+- **Storage in Redis**: All registered servers are stored in Redis for fast retrieval.
+
+### **Health Monitoring & Auto-Removal**
+
+- **Scheduled health checks**: A background process continuously monitors all registered servers.
+- **HTTP-based ping test**: Each server is periodically tested via an HTTP `GET` request to the `/health` endpoint.
+- **Automatic deactivation**: If a server is unresponsive or returns a non-200 status code, it is marked as **unhealthy (`health: false`)**.
+- **Reactivation**: If a previously unhealthy server becomes responsive, it is marked as **healthy (`health: true`)**.
+
+### **Room Allocation & Load Balancing**
+
+- **Load-aware room allocation**: When creating a room, the load balancer selects the server with the **highest available capacity**.
+- **Capacity tracking**: Each time a room is created, the number of **expected consumers** is subtracted from the server’s capacity.
+- **Room deallocation**: When a room is closed, the consumers are freed, and the server’s available capacity is restored.
+
+### **Fault Tolerance & Scalability**
+
+- **Multi-instance support**: The system can be deployed in a **distributed** environment with multiple load balancer instances.
+- **Event-driven updates**: Server states and capacity updates are immediately reflected across all instances via Redis.
+- **Automatic failover**: If a WebRTC server becomes unavailable, new rooms are assigned only to healthy servers.
+
+---
+
+## 📌 **Endpoints**
+
+### ✅ **Register a WebRTC Server**
+
+Registers a new Mediasoup server, calculating its total capacity.
+
+**`POST /register`**
+
+#### 🔹 Request Body:
+
+```json
+{
+  "serverId": "server-001",
+  "serviceUrl": "http://example.com",
+  "workers": 4
+}
+```
+
+#### 🔹 Response:
+
+```json
+{ "message": "Server registered successfully" }
+```
+
+---
+
+### ✅ **Create or Retrieve a Room**
+
+Selects the most capable healthy server and assigns the room.
+
+**`POST rooms/:roomId?`**
+
+#### 🔹 Request Body:
+
+```json
+{
+  "eventNotificationUri": "http://example.com/notify",
+  "maxPeerCount": 3
+}
+```
+
+#### 🔹 Response:
+
+```json
+{
+  "protocol": "2060-mediasoup-v1",
+  "wsUrl": "wss://example.com:443",
+  "roomId": "room-67890"
+}
+```
+
+---
+
+### ✅ **Notify Room Closure**
+
+Updates the server's available capacity when a room is closed.
+
+**`POST /room-closed`**
+
+#### 🔹 Request Body:
+
+```json
+{
+  "serverId": "server-001",
+  "roomId": "room-67890"
+}
+```
+
+#### 🔹 Response:
+
+```json
+{ "message": "Room closed notification processed successfully" }
+```
+
+**Also you can use swagger documentation visit url:** `http://loadbalancer.domain/API`
+
+---
+
+## ⚙️ **Configuration**
+
+The application uses **environment variables** for configuration.
+
+| Variable                | Description                                        | Default Value            |
+| ----------------------- | -------------------------------------------------- | ------------------------ |
+| `APP_PORT`              | The port number on which the application will run. | `3001`                   |
+| `LOG_LEVEL`             | Define log level of the application. 1 to          | `1`                      |
+| `REDIS_URL`             | Redis connection URL                               | `redis://localhost:6379` |
+| `HEALTH_CHECK_INTERVAL` | Health check webrtc-server frequency (ms).         | `30000`                  |
+
+---
+
+## 🏗️ **Architecture & Implementation**
+
+### 🔹 **1. Server Registration Flow**
+
+1. A Mediasoup server sends a `POST /register` request.
+2. If the server is already registered, its entry is removed and re-added.
+3. The server’s total capacity is calculated (`workers × 500` consumers).
+4. The server is stored in Redis with `health: true`.
+
+### 🔹 **2. Health Check Process**
+
+1. Every **30 seconds** (or as defined in `HEALTH_CHECK_INTERVAL`), the system checks all registered servers.
+2. A `GET /health` request is sent to each server.
+3. If the server is **healthy**, its `health` status remains `true`.
+4. If the server is **unhealthy**, its `health` status is updated to `false`.
+
+### 🔹 **3. Room Allocation Flow**
+
+1. A client requests to **create a room** (`POST rooms/:roomId?`).
+2. The load balancer filters out **unhealthy servers**.
+3. The server with the **highest available capacity** is selected.
+4. The expected consumers for the room are **subtracted** from the server’s capacity.
+5. The room is created, and the WebSocket URL is returned.
+
+### 🔹 **4. Room Closure Flow**
+
+1. When a room is **closed**, a `POST /room-closed` request is sent.
+2. The number of consumers freed is **added back** to the server’s available capacity.
+3. The room entry is **deleted** from Redis.
+
+---
+
+## 🔧 **Deployment & Scaling**
+
+### 1️ **Running with Docker**
+
+```sh
+docker-compose up --build
+```
+
+### 2️ **Deploying in Kubernetes**
+
+The load balancer can run **as a microservice** in Kubernetes.
+
+Example `deployment.yaml`:
+
+```yaml
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: webrtc-loadbalancer
+spec:
+  replicas: 3
+  template:
+    spec:
+      containers:
+        - name: webrtc-loadbalancer
+          image: webrtc-loadbalancer:latest
+          env:
+            - name: REDIS_HOST
+              value: 'redis-service'
+            - name: HEALTH_CHECK_INTERVAL
+              value: '30000'
+```
+
+---
+
+## 📜 **License**
+
+This project is licensed under the **Apache-2.0**.
+
+---