Distributed Systems Lab

This project is a multi-module Spring Boot application demonstrating various aspects of distributed systems, including service discovery, configuration management, distributed logging, and distributed data storage.

Project Overview

The project consists of the following modules:

• config-server: Configuration server for the distributed system
• facade-service: Frontend service that interfaces with other services
• logging-service: Service for centralized logging
• message-service: Service for message handling
• hz-cluster: Hazelcast cluster configuration for distributed data storage

Prerequisites

• Java 17
• Maven 3.6+

Setup Instructions

1. Clone the repository:

   git clone <repository-url>
   cd distributed-systems-lab

2. Build the project:

   mvn clean install

Launching the Project

Using Docker (Recommended)

The easiest way to launch all services at once is using Docker Compose:

1. Build the project first:

   mvn clean install

2. Start all services using Docker Compose:

   docker-compose up -d

3. Verify that all services are running:

   docker-compose ps

4. To view logs from all services:

   docker-compose logs

   Or for a specific service:

   docker-compose logs <service-name>

   Example:

   docker-compose logs facade-service

5. To stop all services:

   docker-compose down

Testing the Distributed System

Once all services are running, you can test the functionality using the following endpoints:

1. Send a message:

   curl -X POST -H "Content-Type: text/plain" -d "Hello, Distributed World!" http://localhost:8080/message

2. Retrieve all messages:

   curl http://localhost:8080/messages

Manual Startup

Alternatively, you can start each service manually in the following order:

1. Start the config-server:

   cd config-server
   mvn spring-boot:run

2. Start the hz-cluster:

   cd hz-cluster
   mvn spring-boot:run

3. Start the logging-service:

   cd logging-service
   mvn spring-boot:run

4. Start the message-service:

   cd message-service
   mvn spring-boot:run

5. Start the facade-service:

   cd facade-service
   mvn spring-boot:run

Testing

Running Tests

To run all tests:

mvn test

To run tests for a specific module:

mvn test -pl <module-name>

Example:

mvn test -pl logging-service

To run a specific test class:

mvn test -pl <module-name> -Dtest=<TestClassName>

Example:

mvn test -pl logging-service -Dtest=LoggingServiceTest

Test Coverage

The project includes the following tests:

• config-server: Tests for the configuration server

  • ConfigControllerTest: Tests the configuration controller

• facade-service: Tests for the facade service

  • FacadeControllerTest: Tests the facade controller

• logging-service: Tests for the logging service

  • LoggingServiceTest: Tests the REST logging service
  • GrpcLoggingServiceTest: Tests the gRPC logging service

• message-service: Tests for the message service

  • MessageServiceTest: Tests the message service

• hz-cluster: Tests for the Hazelcast cluster

  • HzClientServiceTest: Tests the Hazelcast client service
  • HazelcastConfigTest: Tests the Hazelcast configuration

API Endpoints

Facade Service

• POST /message: Sends a message to the logging service
• GET /messages: Retrieves all messages from the logging and message services

Logging Service

• GET /messages: Retrieves all messages from the logging service

Message Service

• GET /messages: Retrieves a static message (not implemented yet)

Hz-Cluster

• GET /hz-test: Tests the Hazelcast cluster with a simple counter
• GET /hz-test-pesim: Tests the Hazelcast cluster with pessimistic locking
• GET /hz-test-optimistic: Tests the Hazelcast cluster with optimistic locking

Architecture

The project demonstrates a microservices architecture with the following components:

1. Service Discovery: The config-server provides service discovery for other services.
2. API Gateway: The facade-service acts as an API gateway, routing requests to appropriate services.
3. Distributed Logging: The logging-service provides centralized logging for all services.
4. Distributed Data Storage: The hz-cluster provides distributed data storage using Hazelcast.
5. Circuit Breaking: The facade-service implements circuit breaking using Resilience4j.

Technologies Used

• Spring Boot
• Hazelcast
• gRPC
• Resilience4j
• JUnit 5
• Mockito