REST API microservice in Go

A production-ready REST API boilerplate built with Go, featuring MongoDB integration, comprehensive middleware, flight recorder tracing, and modern development practices.

✨ Highlights

• 🚀 Production-Ready: Graceful shutdown, health checks, structured logging
• 🔒 Security-First: OWASP compliant, multi-tier auth, security headers
• 📊 Observability: Flight recorder tracing, Prometheus metrics, pprof profiling
• 🧪 Test Coverage: 70%+ coverage threshold with parallel testing
• 🐳 Docker-Ready: Multi-stage builds with BuildKit optimization
• 📝 Well-Documented: OpenAPI 3 specification with Postman collection

🚀 Quick Start

# Clone and start
git clone https://github.com/rameshsunkara/go-rest-api-example.git
cd go-rest-api-example
make start

# Your API is now running at http://localhost:8080
curl http://localhost:8080/healthz

📋 Table of Contents

• Features
• Architecture
• Getting Started
• Available Commands
• Tools & Stack
• Contributing

🎯 Key Features

API Features

1. OWASP Compliant Open API 3 Specification: Refer to OpenApi-v1.yaml for details.
2. Production-Ready Health Checks:
   • /healthz endpoint with proper HTTP status codes (204/424)
   • Database connectivity validation
   • Dependency health monitoring
3. Comprehensive Middleware Stack:
   • Request Logging: Structured logging with request correlation
   • Authentication: Multi-tier auth (external/internal APIs)
   • Request ID Tracing: End-to-end request tracking
   • Panic Recovery: Graceful error handling and recovery
   • Security Headers: OWASP-compliant security header injection
   • Query Validation: Input validation and sanitization
   • Compression: Automatic response compression (gzip)
4. Flight Recorder Integration: Automatic trace capture for slow requests using Go 1.25's built-in flight recorder.
5. Standardized Error Handling: Consistent error response format across all endpoints
6. API Versioning: URL-based versioning with backward compatibility
7. Internal vs External APIs: Separate authentication and access controls
8. Model Separation: Clear distinction between internal and external data representations

Go Application Features

1. Configuration Management: Environment-based configuration with validation
2. Graceful Shutdown: Proper signal handling with resource cleanup and connection draining
3. Production-Ready MongoDB Integration:
   • Connection pooling and health checks
   • Functional options pattern for flexible configuration
   • SRV and replica set support
   • Credential management via sidecar files
   • Query logging for debugging
4. Comprehensive Health Checks: /healthz endpoint with database connectivity validation
5. Structured Logging: Zero-allocation JSON logging with request tracing
6. Secrets Management: Secure credential loading from sidecar files
7. Effective Mocking: Interface-based design enabling comprehensive unit testing
8. Database Indexing: Automatic index creation for optimal query performance
9. Idiomatic Go Architecture: Clean separation of concerns with dependency injection
10. Parallel Testing: Race condition detection with atomic coverage reporting
11. Context-Aware Operations: Proper context propagation for cancellation and timeouts
12. Resource Management: Automatic cleanup of connections and resources

Tooling

1. Dockerized Environment: Facilitates service deployment using DOCKER_BUILDKIT.
2. Makefile: Automates common tasks for developers.
3. GitHub Actions: Automates building, testing, code coverage reporting, and enforces the required test coverage threshold.
4. Multi-Stage Docker Build: Accelerates build processes.

🏗️ Architecture

📁 Folder Structure

go-rest-api-example/
├── main.go
├── internal/           # Private application code
│   ├── config/         # Configuration management
│   ├── db/             # Database repositories and data access
│   ├── errors/         # Application error definitions
│   ├── handlers/       # HTTP request handlers
│   ├── middleware/     # HTTP middleware components
│   ├── models/         # Domain models and data structures
│   ├── server/         # HTTP server setup and lifecycle
│   ├── utilities/      # Internal utilities
│   └── mockData/       # Test and development data
├── pkg/                # Public packages (can be imported)
│   ├── logger/         # Structured logging utilities
│   └── mongodb/        # MongoDB connection management
├── localDevelopment/   # Local dev setup (DB init scripts, etc.)
├── Makefile            # Development automation
├── Dockerfile          # Container image definition
├── docker-compose.yaml # Local development services
├── OpenApi-v1.yaml     # API specification
└── OpenApi-v1.postman_collection.json

➡️ Control Flow

flowchart LR
   Request e1@==> Server
   e1@{ animate: true }
   Server e2@==> Router
   e2@{ animate: true }
   M@{ shape: processes, label: "Middlewares" }
   Router e3@==> M
   e3@{ animate: true }
   C@{ shape: processes, label: "Handlers" }
   M e4@==> C
   e4@{ animate: true }
   R@{ shape: processes, label: "Repos(DAO)" }
   C e5@==> R
   e5@{ animate: true }
   id1[(Database)]
   R e6@==> id1
   e6@{ animate: true }

Loading

1. Request: Server receives the incoming request.
2. Server: Server processes the request and forwards it to the router.
3. Router: Router directs the request to the appropriate middleware(s).
4. Middlewares: The middlewares handle various tasks such as logging, authentication, security headers, tracing etc.,
5. Handlers: The request is passed to the appropriate handler, which validates the request and forwards it to the repository layer.
6. Repos(DAO): The repository layer communicates with the database to perform CRUD operations.

🚀 Getting Started

Prerequisites

• Docker and Docker Compose
• Make

Start the Application

git clone https://github.com/rameshsunkara/go-rest-api-example.git
cd go-rest-api-example
make start

Your API is now running at http://localhost:8080

Try it out:

curl http://localhost:8080/api/v1/healthz
curl http://localhost:8080/api/v1/orders

📟 Available Commands

Essential Commands

start                          Start all necessary services and API server
run                            Run the API server (requires dependencies running)
setup                          Start only dependencies (MongoDB)
test                           Run tests with coverage

Development Commands

lint                           Run the linter
lint-fix                       Run the linter and fix issues
trace                          Analyze a trace file (usage: make trace TRACE_FILE=./traces/slow-request-GET-orders-1234567890.trace)
clean                          Clean all Docker resources (keeps database data)
clean-all                      Clean all Docker resources including volumes (removes database data)
coverage                       Generate and display the code coverage report

CI/CD Commands

build                          Build the API server binary
ci-coverage                    Check if test coverage meets the threshold
format                         Format Go code
version                        Display the current version of the API server

Docker Commands

docker-build                   Build the Docker image
docker-start                   Build and run the Docker container
docker-clean                   Clean all Docker resources

💡 Tip: Run make help to see all available commands.

Additional Prerequisites for Development

• golangci-lint - For linting
• docker-buildx - For multi-platform builds

🛠 Tools & Stack

Category	Technology
Web Framework	Gin
Logging	zerolog
Database	MongoDB
Container	Docker + BuildKit
Tracing	Go 1.25 Flight Recorder
Profiling	pprof

📚 Additional Resources

Roadmap

Click to expand planned features

• Add comprehensive API documentation with examples
• Implement database migration system
• Add distributed tracing (OpenTelemetry integration)
• Add metrics collection and Prometheus integration
• Add git hooks for pre-commit and pre-push
• Implement all remaining OWASP security checks

Nice to Have

Future enhancements

• Enhanced Data Models: Add validation, relationships, and business logic
• Cloud Deployment: Kubernetes manifests and Helm charts
• Advanced Monitoring: APM integration, alerting, and dashboards
• Caching Layer: Redis integration for performance optimization
• Multi-database Support: PostgreSQL, CockroachDB adapters
• Performance Testing: Load testing scenarios and benchmarks

References

• gin-boilerplate
• go-rest-api
• go-base

🤝 Contribute

Contributions are welcome! Here's how you can help:

• 🐛 Found a bug? Open an issue
• 💡 Have a feature idea? Start a discussion
• 🔧 Want to contribute code? Fork the repo and submit a PR

📖 Why This Project?

After years of developing Full Stack applications using ReactJS and JVM-based languages, I found existing Go boilerplates were either too opinionated or too minimal. This project strikes a balance:

✅ Just Right: Not too bloated, not too minimal ✅ Best Practices: Follows Go idioms and patterns ✅ Production-Tested: Battle-tested patterns from real-world applications ✅ Flexible: Easy to customize for your specific needs

What This Is NOT

❌ A complete e-commerce solution ❌ A framework that does everything for you ❌ The only way to structure a Go API

This is a solid foundation to build upon. Take what you need, leave what you don't.

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