Auth Service

1. Introduction

The Authentication Service (Auth Service) is a critical component within the Komerce microservices ecosystem, dedicated to managing all aspects of user authentication and authorization. Its primary objective is to provide a secure, scalable, and reliable mechanism for verifying user identities and controlling access to various internal and external resources.

This service acts as the central authority for identity management, ensuring that only legitimate and authorized users can interact with Komerce applications and data.

2. Core Responsibilities

The Auth Service encapsulates the following key functionalities:

• User Registration & Management: Facilitates the secure creation of new user accounts, including data validation and initial credential setup. It also handles subsequent user profile updates and account status management.
• User Authentication: Verifies user identities against stored credentials (e.g., username/password) during login attempts, supporting various authentication flows.
• Token Issuance & Validation: Generates, signs, and validates JSON Web Tokens (JWTs) or similar access tokens upon successful authentication. These tokens are used by client applications to prove identity to other services.
• Authorization & Role-Based Access Control (RBAC): Manages user roles and permissions, enabling other services to enforce fine-grained access control based on the authenticated user’s privileges.
• Password Management: Provides secure mechanisms for password hashing, storage, and recovery (e.g., password reset flows).
• Session Management: Manages active user sessions, including token revocation and session termination.

3. Technology Stack

The Auth Service is built upon a robust and modern technology stack designed for performance and security:

• Backend Framework: Node.js with Express.js for building efficient and scalable RESTful APIs.
• Database: MongoDB, a NoSQL database, chosen for its flexibility in handling user profiles and its scalability for high-volume authentication requests.
• Authentication Protocol: JSON Web Tokens (JWT) for stateless, secure, and compact transmission of information between parties as a JSON object. This enables efficient authentication across microservices.
• Password Hashing: bcrypt for strong, one-way hashing of passwords, protecting against brute-force attacks and rainbow table lookups.
• Containerization: Docker for packaging the application and its dependencies, ensuring consistent deployment across environments.

4. Architecture Overview

The Auth Service operates as an independent microservice, communicating with other services primarily through its well-defined REST API. It is designed to be horizontally scalable to handle increasing user loads without impacting performance.

Key Architectural Principles:

• Statelessness (for JWTs): Once a JWT is issued, the service does not need to store session information on the server, reducing server load and simplifying scaling.
• Loose Coupling: Other services rely on the Auth Service for authentication and authorization but are not tightly coupled to its internal implementation details.
• High Availability: Designed for redundancy and fault tolerance to ensure continuous authentication capabilities.

sequenceDiagram
    participant Client
    participant AuthService as Auth Service
    participant Gateway as API Gateway
    participant OtherService as Other Service

    Client->>+AuthService: POST /api/v1/auth/login (credentials)
    AuthService->>-Client: 200 OK (JWT)

    Client->>+Gateway: Request to Other Service (with JWT in Header)
    Gateway->>+AuthService: Validate JWT (internal call)
    AuthService->>-Gateway: JWT Valid / Invalid
    Gateway->>+OtherService: Forward Request (if JWT valid)
    OtherService->>-Gateway: Response
    Gateway->>-Client: Response

    Note over Client,AuthService: Subsequent requests use JWT for authentication

5. API Endpoints

All API endpoints are prefixed with /api/v1/auth.

Method	Endpoint	Description	Request Body (Example)	Response (Example)
POST	/register	Registers a new user account.	{"username": "newuser", "password": "securepass"}	{"message": "User registered successfully"}
POST	/login	Authenticates a user and issues an access token.	{"username": "user123", "password": "mypass"}	{"token": "eyJ...", "expiresIn": 3600}
POST	/logout	Invalidates a user’s active session/token.	{"token": "eyJ..."}	{"message": "Logged out successfully"}
GET	/validate	Validates an access token. (Internal use)	(None)	{"isValid": true, "userId": "abc", "roles": ["admin"]}
POST	/password/reset/request	Initiates the password reset process.	{"email": "user@example.com"}	{"message": "Password reset email sent"}
POST	/password/reset/confirm	Confirms password reset with a token and new password.	{"token": "reset_token", "newPassword": "newsecurepass"}	{"message": "Password reset successful"}

6. Security Considerations

Given its critical role, the Auth Service implements several security best practices:

• HTTPS/SSL: All communication with the Auth Service must occur over HTTPS to ensure data encryption in transit.
• Password Hashing: Passwords are never stored in plain text; they are always hashed using bcrypt with a strong salt.
• JWT Security: JWTs are signed with strong cryptographic keys. Best practices for token expiration, revocation, and refresh token mechanisms are applied.
• Rate Limiting: Implemented on authentication endpoints to mitigate brute-force and denial-of-service attacks.
• Input Validation: Strict validation is applied to all incoming data to prevent injection attacks and other vulnerabilities.

7. Scalability & Reliability

The Auth Service is designed for high availability and horizontal scalability:

• Containerization: Facilitates easy deployment and scaling across multiple instances.
• Load Balancing: Can be deployed behind a load balancer to distribute traffic and ensure high availability.
• Stateless Design: Reduces the complexity of scaling by eliminating the need for session stickiness for JWT-based authentication.

8. Integration Guide (High-Level)

Other services and client applications integrate with the Auth Service as follows:

1. Authentication: Clients send credentials to the Auth Service’s /login endpoint to obtain a JWT.
2. Authorization: Clients include the obtained JWT in the Authorization: Bearer <token> header for all subsequent requests to other protected services.
3. Token Validation: Protected services (often via an API Gateway or middleware) forward the JWT to the Auth Service’s internal /validate endpoint to verify its authenticity and extract user claims (e.g., user ID, roles) before processing the request.

For detailed integration instructions, refer to the respective client or service documentation.