This project is a Library Management System developed as a Microservices Architecture using Java. It serves as a project to demonstrate the implementation of microservices using modern Java technologies.
The Microservices architecture is designed with clean separation of concerns, enabling scalability, maintainability, and testability. Each microservice is divided into three key layers: Domain, Infrastructure, and Application, ensuring clear boundaries between business logic, technical concerns, and framework-specific components. Also, it uses Command and query separation pattern
The Domain layer represents the core of the service. It contains the essential business logic and entities, following domain-driven design principles. This layer is entirely framework-agnostic and free of any external dependencies, making it easy to test and highly portable. Key elements include:
- Entities: Represent the core business models.
- Command/Query: Contain the business logic and enforce rules specific to the domain.
- Interfaces: Define contracts (abstractions) that the outer layers (like Infrastructure) must implement, ensuring inversion of control and high modularity.
The Infrastructure layer deals with the technical aspects of the application, providing implementations for interacting with external systems such as databases or third-party APIs. It serves as the bridge between the domain and the underlying technology stack. Key components include:
- Persistence Layer: Implements domain interfaces (e.g., repositories) using Spring Data JPA to interact with a MySQL database, ensuring seamless data management.
- External Services: Manages any API calls or third-party service interactions necessary for the business.
- Data Mappers: Transforms data between the domain model and persistence model.
The Application layer, also known as the Spring layer, is where the service integrates with the Spring framework. It handles the configuration, external APIs, and communication with other services. This layer encapsulates:
- Controllers: Handle HTTP requests and direct them to the appropriate domain services.
- Exception Handling: Global error handling through Controller Advice, ensuring standardized responses across the service.
- Configuration: Contains all the necessary Spring configurations such as beans, security settings, and transactional boundaries.
- Java 21: Core programming language.
- Spring Boot: Framework for building microservices.
- Spring Cloud: For managing microservices, service discovery, and load balancing.
- Eureka: Service registry for microservices.
- MySQL: Relational database for persistent storage.
- Docker: Containerization of microservices.
- Swagger/OpenAPI: API documentation and testing.
- JUnit & Mockito: Testing frameworks for unit and integration testing.
- Flyway: Database migration tools.
- Lombok: Reducing boilerplate code.
- Grafana: For observability and monitoring services through dashboards.
- loki: For centralized logging.
- tempo: For distributed tracing.
- Java 21
- Maven
- Docker
- Docker Compose
-
git clone https://github.com/arivan-amin/Library-Microservices.git cd Library-Microservices -
cd Core ../mvnw clean install cd ..
-
Go to project root and build the project, and it will load the images to your local docker repository using JIB:
./mvnw clean package
-
- on Linux: add the below variables to your .bashrc file and reload or reboot
export EUREKA_USER=admin export EUREKA_PASSWORD=admin
- on Windows: run the below commands
set EUREKA_USER=admin set EUREKA_PASSWORD=admin
-
docker compose up -d
-
- API Gateway:
http://localhost:8080 - Eureka Dashboard:
http://localhost:8080/eureka/web - credentials are username: admin password: admin
- Swagger UI:
http://localhost:8080/swagger-ui.html - Grafana:
http://localhost:3000/dashboards
- API Gateway:
-
Unit and tests are available for each microservice.
-
Run the tests using Maven:
./mvnw test
-
http://localhost:8080/swagger-ui.html
Since you run the docker compose command all the services are running now, you can call the endpoints
Postman import file is provided In the root project directory named Library-Microservices.postman_collection.json.
-
admin:admin@localhost:8080/api/books -
admin:admin@localhost:8080/api/books/0425f682-0781-4565-bd01-caf3585b2ff6 -
admin:admin@localhost:8080/api/books/0001b624-24ba-4f45-bb50-0eebc6d509e8 -
admin:admin@localhost:8080/api/books -
admin:admin@localhost:8080/api/books/0425f682-0781-4565-bd01-caf3585b2ff6
```
{
"isbn":"4523523452345",
"title":"Jude the Obscure",
"author":"Thomas Hardy",
"publicationYear":"2020"
}
```
-
admin:admin@localhost:8080/api/patrons -
admin:admin@localhost:8080/api/patrons/0425f682-0781-4565-bd01-caf3585b2ff6 -
admin:admin@localhost:8080/api/patrons/0001b624-24ba-4f45-bb50-0eebc6d509e8 -
admin:admin@localhost:8080/api/patrons -
admin:admin@localhost:8080/api/patrons/0425f682-0781-4565-bd01-caf3585b2ff6
```
{
"name":"john smith",
"contactInformation":"new york, 445th street"
}
```
-
admin:admin@localhost:8080/api/borrow/0425f682-0781-4565-bd01-caf3585b2ff6/patron/2e82413d-48c8-4fb9-b592-1df88723a756 -
admin:admin@localhost:8080/api/return/0425f682-0781-4565-bd01-caf3585b2ff6/patron/2e82413d-48c8-4fb9-b592-1df88723a756
The system is divided into several microservices, each responsible for a specific domain:
- API Gateway: Serves as the single entry point for all client requests, routing them to the appropriate microservices. It handles request aggregation, load balancing, and provides a centralized point for managing cross-cutting concerns such as authentication and logging.
- Core Service: Provides foundational services and shared functionality used across other microservices. This could include utility functions, common data access layers, or basic service management features.
- Discovery Server: Implements service discovery mechanisms, allowing microservices to find and communicate with each other dynamically. It maintains a registry of available services and their locations.
- Book Service: Manages book records.
- Patron Service: Manages patron records.
- Borrow Service: Manages borrowing records.
- Name: Arivan Amin
- Email: [email protected]