Olara Gateway Service (Java)

Welcome to the Olara Gateway Service! This project serves as the API gateway for the Olara platform, handling routing, authentication, authorization, and service discovery for all backend microservices.

🚀 Project Overview

The gateway acts as a single entry point for all client requests, forwarding them to the appropriate backend services. It enforces security, manages cross-cutting concerns, and simplifies client interactions with the microservices architecture.

✨ Features

Dynamic Routing via routes.json
JWT Authentication & Role-based Authorization (Keycloak integration)
Tenant-aware Routing
Service Discovery (Eureka)
Resilience (Circuit Breaker, Retry, Rate Limiting via Resilience4j)
Centralized Logging (Loki, Spring Logging)
Swagger API Docs Proxying (Gateway exposes and proxies Swagger/OpenAPI docs from backend services at /swagger/{service})

🏗️ Architecture

+---------+      +-------------------+      +-------------------+
|  Client | ---> |  Gateway Service  | ---> |  Microservices    |
+---------+      +-------------------+      +-------------------+
                        |                        |
                        |                        +-- user-service
                        |                        +-- order-service
                        |                        +-- payment-service
                        |                        +-- wallet-service
                        |                        +-- stockmarket-service
                        |                        +-- kyc-service
                        |
                        +-- Eureka Discovery
                        +-- Keycloak Auth

🛠️ Technologies Used

Java 17+
Spring Cloud Gateway
Spring Security (OAuth2, JWT)
Keycloak
Eureka (Service Discovery)
Resilience4j
Loki (Logging)
Gradle

⚙️ Configuration

Environment Files

application.yml (base)
application-local.yml (local dev)
application-uat.yml (UAT)

Route Configuration

All routes are defined in src/main/resources/routes.json
Each route specifies:
paths: URL patterns
uri: Target service
roles, permissions: Access control
requiresTenantId, requiresRoles, isAuthenticated: Security flags

Keycloak

Used for authentication and role-based access
Configured via application-*.yml files
JWT tokens are validated for protected routes

🏃‍♂️ Running the Service

Prerequisites

Java 17+
Gradle
Docker (for running dependencies like Keycloak, Eureka, Loki)

Local Development

Clone the repo:

git clone https://github.com/olara-tech/gateway-service-java.git
cd gateway-service-java

Start dependencies:

docker-compose -f docker-compose-uat.yml up -d

Run the gateway:

./gradlew bootRun --args='--spring.profiles.active=local'

UAT/Production

Set environment variables and use application-uat.yml.
Deploy with Docker or your preferred orchestrator.

🌐 API Gateway Routing

All requests are matched against routes.json.

Example route:

{
  "routeId": "user-service-customer",
  "paths": ["/api/v1/profile/**"],
  "uri": "lb://user-service",
  "isAuthenticated": true
}

The gateway enforces authentication and forwards the request to the correct service.

Swagger API Docs Proxying

The gateway exposes and proxies Swagger/OpenAPI documentation endpoints from backend services.
Access Swagger docs for a service via:
```
GET /swagger/{service}
```
For example, /swagger/user-service proxies the Swagger UI or OpenAPI docs from the user-service backend.
This allows you to view and interact with the API documentation for each microservice through a unified gateway endpoint.
The proxying logic is handled in the gateway routing configuration and/or filter classes (see GatewayRouter and GatewayFilterFactory).

🔒 Security & Auth

JWT tokens are required for most routes (see isAuthenticated in routes.json).
Role and tenant checks are enforced as configured.
Keycloak is the identity provider.

📋 Logging & Troubleshooting

Logs are output to console and can be shipped to Loki.
Log level can be set in application-*.yml (e.g., com.olara.gatewayservice: DEBUG for verbose logs).
For troubleshooting route issues:
Check logs for route matching and header extraction.
Ensure your JWT contains required claims (tenantId, userId).
Review routes.json for correct path and security settings.

🤝 Contributing

Fork the repo
Create your feature branch (git checkout -b feature/your-feature)
Commit your changes
Push to the branch
Open a Pull Request

📄 License

This project is licensed under the MIT License. See LICENSE for details.

📞 Support

For questions or support, please open an issue or contact the Olara Tech team.