Library Management System (Microservices)

A Library Management System built as a set of microservices that demonstrates:

• Spring IoC / Dependency Injection
• Java Stream API analytics
• Intermediate native SQL query in borrowing-service
• Database-per-service PostgreSQL setup
• Dockerized services orchestrated with Docker Compose

Services

• book-service (:8081) - book metadata
• member-service (:8082) - library member data
• borrowing-service (:8083) - checkout/return flow + native SQL stats
• reporting-service (:8084) - cross-service analytics using Java Streams

Each service is a Spring Boot application, uses PostgreSQL as its own database (database‑per‑service), and communicates via REST APIs. Docker Compose orchestrates all services and databases.

Run with Docker Compose

docker compose up --build

Example API calls

Create book:

curl -X POST http://localhost:8081/api/books \
  -H "Content-Type: application/json" \
  -d '{"title":"Clean Code","author":"Robert C. Martin","genre":"Software","isbn":"9780132350884","totalCopies":5}'

Create member:

curl -X POST http://localhost:8082/api/members \
  -H "Content-Type: application/json" \
  -d '{"name":"Alice","email":"[email protected]","membershipStatus":"ACTIVE"}'

Upsert member reference into borrowing database (for native SQL join):

curl -X POST http://localhost:8083/api/borrowings/member-ref \
  -H "Content-Type: application/json" \
  -d '{"id":1,"name":"Alice"}'

Checkout:

curl -X POST http://localhost:8083/api/borrowings/checkout \
  -H "Content-Type: application/json" \
  -d '{"memberId":"1","bookId":"1","dueDate":"2026-05-05"}'

Return:

curl -X POST "http://localhost:8083/api/borrowings/1/return?returnDate=2026-05-10"

Native SQL member stats:

curl "http://localhost:8083/api/borrowings/stats/members?startDate=2026-01-01&minBorrows=0"

Top books report (Java Streams):

curl "http://localhost:8084/api/reports/top-books?topN=5"