🎟️ Microservices-based Ticketing Platform

A sample ticketing system demonstrating microservice architecture with Spring Boot and gRPC.

Architecture

graph TD
    Client -->|HTTP| Gateway[API Gateway]
    Gateway -->|JWT Auth| Auth[Auth Service]
    Gateway -->|REST| Catalog[Catalog Service]
    Gateway -->|REST| Booking[Booking Service]
    Booking <-->|gRPC| Inventory[Inventory Service]
    Auth -->|JPA| AuthDB[(Auth DB)]
    Catalog -->|JPA| CatalogDB[(Catalog DB)]
    Inventory -->|JPA| InventoryDB[(Inventory DB)]
    Booking -->|JPA| BookingDB[(Booking DB)]

Loading

• Each service's data is isolated in its own PostgreSQL database (auth, catalog, inventory, booking).

Each service runs independently on its own port:

Service	Port	Description
Gateway	8080	Routes external requests and performs coarse-grained auth
Catalog	8081	Events, venues and price tiers
Inventory	8082 (gRPC 9090)	Seat availability and locking
Booking	8083	Orchestrates booking workflow
Auth	8084	User registration and token issuance

• The ticketing-shared-lib module holds protobuf definitions used by inventory and booking.

Request workflow

1. Authenticate
   Users register and log in via the Auth Service to obtain a JWT.
2. Browse catalog
   Clients call the Gateway which forwards requests to the Catalog Service for events and seating info.
3. Start a booking
   The Booking Service initiates a booking through the Gateway and asks the Inventory Service (via gRPC) to lock seats.
4. Confirm or cancel
   After payment confirmation the Booking Service finalizes the order and tells Inventory to sell seats. Cancellation releases the locks.

Repository structure

├─ ticketing-auth-service       # JWT issuance and user management
├─ ticketing-catalog-service    # Event and venue data
├─ ticketing-inventory-service  # Seat management exposed over gRPC
├─ ticketing-booking-service    # Booking orchestration
├─ ticketing-gateway-service    # API gateway / edge service
├─ ticketing-shared-lib         # Protobuf definitions shared across services
└─ ticketing-platform.postman_collection.json  # Example API requests

Run with Docker Compose

To build and start all services along with PostgreSQL, ensure Docker is running and execute:

docker compose up --build

The stack exposes the gateway at http://localhost:8080.

Run locally

Prerequisites

• JDK 21
• Maven
• Docker (for PostgreSQL)
• JWT_SECRET environment variable (same for all services)

Steps

1. Clone the repository

   git clone <repo-url>
   cd microservices-based-ticketing-platform

2. Build shared protobuf library

   cd ticketing-shared-lib
   ./mvnw install
   cd ..

3. Start PostgreSQL

   docker run --name ticketing-postgres -e POSTGRES_PASSWORD=postgres -p 5432:5432 -d postgres

   Create databases catalog, inventory, and booking inside the container.

4. Run each service (in separate terminals)

   export JWT_SECRET=supersecret
   cd ticketing-catalog-service && ./mvnw spring-boot:run
   cd ticketing-inventory-service && ./mvnw spring-boot:run
   cd ticketing-booking-service && ./mvnw spring-boot:run
   cd ticketing-auth-service && ./mvnw spring-boot:run
   cd ticketing-gateway-service && ./mvnw spring-boot:run

5. Use the platform

   Access APIs through the gateway at http://localhost:8080/api/...
   A Postman collection ticketing-platform.postman_collection.json is provided for example requests.

JWT Secret Configuration

All services use a shared HMAC secret to sign and validate JWT tokens. The auth service signs tokens while the gateway and downstream services re-validate them using the same secret.

Configure the secret via the JWT_SECRET environment variable or the jwt.secret property in each service's application.properties. The value must be identical across all services to ensure validation succeeds.

Rotating the secret

1. Provide a new value for JWT_SECRET and redeploy all services so they can validate tokens signed with the new secret.
2. Restart the auth service last to begin issuing tokens with the new secret.
3. After previously issued tokens expire, remove the old secret value from your configuration.

License

This project is licensed under the MIT License.