Distributed Microservices Demo in Go

A cloud-native, production-ready demonstration of a distributed system built with Go. This project features three containerized microservices (REST & gRPC) communicating over a network, backed by PostgreSQL, deployed via CI/CD to AWS ECS, and fully monitored with Prometheus and Grafana.

Demo

Run Locally:

make run_docker

Prerequisites: Docker and Docker Compose must be installed on your machine.

Architecture Overview

graph TB
    subgraph AWS ECS / Docker Compose
        A[Client] --> B[API Gateway]
        B --> C[User Service]
        C --> E[(User DB)]
        C -- gRPC --> G[Point Service]
        G --> H[(Point DB)]
        B --> D[Department Service]
        D --> F[(Department DB)]
    end

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Technology Stack

Go, PostgreSQL, Docker, gRPC, Prometheus, Grafana, GitHub Action

Key Features

🏗️ Architecture & Design Patterns

This project is a textbook example of practical software engineering patterns in Go:

• Concurrency Pattern:
  • Utilized in service/user_service/user/user_service to execute multiple database queries and gRPC calls concurrently using Go's errgroup.
  • Enhances the performance of the GetAllUserStatistics method by leveraging parallel processing.
• Dependency Injection Pattern:
  • Utilized in lib/container/container.go to manage logging, database connections, and environment variables.
  • Promotes modularity and flexibility by injecting dependencies into a central container.
• Singleton Pattern:
  • Implemented in lib/container/container.go through synchronized lazy initialization (sync.Mutex + instance check) in PostgresAdapter and MySQLAdapter.
  • Ensures only one database connection instance is created per adapter while maintaining thread safety.
• Adapter Pattern:
  • Used in lib/container/container.go to create a unified database interface (Db) with concrete implementations (PostgresAdapter and MySQLAdapter).
  • Enables seamless switching between database providers without modifying client code.
• Factory Pattern:
  • Utilized in lib/container/db.go through the NewDBConnectionAdapter function.
  • Acts as a factory method to create instances of different database adapters based on the specified database type, encapsulating object creation logic.
• External Configuration Pattern:
  • Utilized in lib/container/container.go to manage and validate essential configuration through environment variables.
  • Ensures centralized and type-safe access to settings, promoting flexibility and ease of deployment.
• Decorator Pattern:
  • Utilized in lib/response/response.go to dynamically add behaviors to response handlers.
  • Allows setting headers or handling different response types without altering the underlying handler implementation.
• Middleware Pattern:
  • Utilized in lib/router/router.go to chain multiple handlers that add functionalities like logging, request ID management, and Prometheus metrics collection.
  • Enhances the HTTP request processing pipeline with modular and reusable components.
• Object Pool Pattern:
  • Implemented in lib/container/connection.go to manage a pool of reusable gRPC client connections.
  • Optimizes resource usage and improves performance by reducing the overhead of repeatedly creating and destroying connections.

🚀 Operational Excellence

• CI/CD: Automated Docker image builds and deployments to AWS ECS via GitHub Actions.
• Monitoring: Integrated Prometheus metrics and pprof profiling for real-time performance insight.
• Observability: Structured logging and request tracing throughout the services.
• Containerization: Fully dockerized for local development and cloud deployment.

🧪 Testing Strategy

• Unit Tests: Comprehensive tests for all business logic and handlers.
• Integration Tests: End-to-end tests using a live test database and gRPC server within Docker, validating the entire service ecosystem.

📡 APIs & Communication

• RESTful APIs: JSON over HTTP for user-service (/users) and department-service (/departments).
• gRPC: High-performance RPC for internal communication between user-service and point-service.

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Conclusion

This microservices architecture not only demonstrates best practices in software design but also incorporates essential features for modern application development, such as CI/CD, performance monitoring, and robust testing frameworks. By leveraging these technologies, developers can build scalable, maintainable, and high-performing applications.