dance-lessons-coach/AGENTS.md

DanceLessonsCoach - AI Agent Documentation

This file documents the AI agents, tools, and development workflow for the DanceLessonsCoach project.

🎯 Project Overview

DanceLessonsCoach is a Go-based web service with CLI capabilities, featuring:

• RESTful JSON API with Chi router
• High-performance Zerolog logging
• Interface-based architecture
• Context-aware services
• Comprehensive testing

📋 Development Timeline

Phase 1: Foundation (Completed ✅)

• Go 1.26.1 environment setup
• Project structure with cmd/ and pkg/ directories
• Core Greet service implementation
• CLI interface
• Unit tests

Phase 2: Web API (Completed ✅)

• Chi router integration
• Versioned API endpoints (/api/v1)
• Health endpoint (/api/health)
• JSON responses with proper headers

Phase 3: Logging & Architecture (Completed ✅)

• Zerolog integration with Trace level
• Context-aware logging
• Interface-based design patterns
• Dependency injection

Phase 4: Documentation & Testing (Completed ✅)

• Comprehensive AGENTS.md
• README.md with usage instructions
• Server management guide
• API endpoint documentation

Phase 5: Configuration Management (Completed ✅)

• Viper integration for configuration
• Environment variable support with DLC_ prefix
• Customizable server host/port
• Configurable shutdown timeout
• Configuration validation and logging
• Example configuration file

🛠️ Tools & Technologies

Component	Technology	Version
Language	Go	1.26.1
Router	Chi	v5.2.5
Logging	Zerolog	v1.35.0
Configuration	Viper	v1.21.0
Testing	Standard Library	-
Dependency Management	Go Modules	-

🗺️ Project Structure

DanceLessonsCoach/
├── cmd/
│   ├── greet/          # CLI application
│   │   └── main.go
│   └── server/         # Web server
│       └── main.go
├── pkg/
│   ├── config/         # Configuration management
│   │   └── config.go    # Viper-based config
│   ├── greet/          # Core domain logic
│   │   ├── api_v1.go    # API handlers
│   │   ├── greet.go     # Service implementation
│   │   └── greet_test.go # Unit tests
│   └── server/         # HTTP server
│       └── server.go
├── go.mod              # Dependencies
├── go.sum              # Dependency checksums
├── config.example.yaml # Configuration template
├── README.md           # User documentation
├── AGENTS.md           # This file
└── .gitignore          # Ignore patterns

🚀 Server Management

Starting the Server

# Navigate to project directory
cd /Users/gabrielradureau/Work/Vibe/DanceLessonsCoach

# Run server in background
go run cmd/server/main.go &

Expected output:

Server running on :8080
[INF] Starting HTTP server on :8080
[TRC] Registering greet routes
[TRC] Greet routes registered

Features:

• Context-aware server initialization
• Graceful shutdown handling
• Signal-based termination (SIGINT, SIGTERM)
• 30-second shutdown timeout
• Proper resource cleanup

Configuration Management

The server supports flexible configuration through environment variables with the DLC_ prefix:

Available Configuration Options:

Option	Environment Variable	Default Value	Description
Host	DLC_SERVER_HOST	0.0.0.0	Server bind address
Port	DLC_SERVER_PORT	8080	Server listening port
Shutdown Timeout	DLC_SHUTDOWN_TIMEOUT	30s	Graceful shutdown timeout

Usage Examples:

# Custom port
export DLC_SERVER_PORT=9090
go run cmd/server/main.go &

# Custom host and port
export DLC_SERVER_HOST="127.0.0.1"
export DLC_SERVER_PORT=8081
go run cmd/server/main.go &

# Custom shutdown timeout
export DLC_SHUTDOWN_TIMEOUT=45s
go run cmd/server/main.go &

Configuration File Support:

A config.example.yaml file is provided as a template. By default, the application looks for config.yaml in the current working directory.

To specify a custom config file path, set the DLC_CONFIG_FILE environment variable:

DLC_CONFIG_FILE="/path/to/config.yaml" go run ./cmd/server

Example config.yaml:

server:
  host: "0.0.0.0"
  port: 8080

shutdown:
  timeout: 30s

Configuration Loading:

• File-based configuration takes highest precedence
• Environment variables override defaults but are overridden by config file
• Default values are used when no other configuration is provided
• All configuration is validated on startup
• Invalid configurations cause server startup failure
• Configuration values and source are logged at startup

Verification:

# Test with custom configuration
DLC_SERVER_PORT=9090 DLC_SERVER_HOST="127.0.0.1" go run cmd/server/main.go

# Verify it's running on the custom port
curl http://127.0.0.1:9090/api/health
# Expected: {"status":"healthy"}

Checking Server Status

# Check health endpoint
curl -s http://localhost:8080/api/health

Expected response: {"status":"healthy"}

Stopping the Server

To stop the server gracefully:

# Send SIGTERM for graceful shutdown
kill -TERM $(lsof -ti :8080)

# Or send SIGINT (Ctrl+C equivalent)
pkill -INT -f "go run"

Graceful shutdown process:

1. Server receives termination signal
2. Logs shutdown message
3. Stops accepting new connections
4. Waits up to 30 seconds for active requests to complete
5. Closes all connections cleanly
6. Exits with proper cleanup

For force stop (if graceful shutdown hangs):

kill -9 $(lsof -ti :8080)

Verification:

curl -s http://localhost:8080/api/health
# Should return connection refused

🌐 API Endpoints

Base URL

http://localhost:8080

Health Check

GET /api/health

Response:

{"status":"healthy"}

Greet Service

GET /api/v1/greet/
GET /api/v1/greet/{name}

Examples:

# Default greeting
curl http://localhost:8080/api/v1/greet/
# Response: {"message":"Hello world!"}

# Personalized greeting
curl http://localhost:8080/api/v1/greet/John
# Response: {"message":"Hello John!"}

# Another example
curl http://localhost:8080/api/v1/greet/Alice
# Response: {"message":"Hello Alice!"}

🔧 Development Workflow

1. Check Server Status

curl -s http://localhost:8080/api/health

2. Start Development Server

cd /Users/gabrielradureau/Work/Vibe/DanceLessonsCoach
go run cmd/server/main.go &

3. Test API Endpoints

# Test all endpoints as shown above
curl http://localhost:8080/api/v1/greet/YourName

4. Run Tests

# Run all tests
go test ./...

# Run specific package
go test ./pkg/greet/

5. Make Changes

• Edit source files in pkg/ or cmd/
• Follow existing patterns and interfaces
• Add tests for new functionality

6. Stop and Restart

pkill -f "go"
go run cmd/server/main.go &

🧪 Testing

Unit Tests

# Run all tests
go test ./...

# Run with verbose output
go test -v ./...

# Run specific test
go test ./pkg/greet/ -run TestService_Greet

CLI Testing

# Default greeting
go run ./cmd/greet
# Output: Hello world!

# Personalized greeting
go run ./cmd/greet John
# Output: Hello John!

API Testing

# Health check
curl http://localhost:8080/api/health

# Greet endpoints
curl http://localhost:8080/api/v1/greet/John
curl http://localhost:8080/api/v1/greet/

📝 Architecture Decisions

Interface-Based Design

type Greeter interface {
    Greet(ctx context.Context, name string) string
}

Benefits:

• Easy mocking for tests
• Dependency injection
• Multiple implementations
• Clear contracts

Context-Aware Services

func (s *Service) Greet(ctx context.Context, name string) string {
    log.Trace().Ctx(ctx).Str("name", name).Msg("Greet function called")
    // ...
}

Benefits:

• Request tracing
• Cancellation support
• Deadline propagation
• Metadata passing

Server Context Management

// Root context with cancellation
ctx, cancel := context.WithCancel(context.Background())
defer cancel()

// Server context with graceful shutdown
serverCtx, serverStop := context.WithCancel(ctx)

// HTTP server with context-aware shutdown
srv := &http.Server{
	Addr:    ":8080",
	Handler: server.Router(),
}

// Graceful shutdown with timeout
shutdownCtx, shutdownCancel := context.WithTimeout(
	context.Background(), 
	30*time.Second
)
defer shutdownCancel()

if err := srv.Shutdown(shutdownCtx); err != nil {
	log.Error().Err(err).Msg("Server shutdown failed")
}

Benefits:

• Graceful shutdown handling
• Signal-based termination (SIGINT, SIGTERM)
• 30-second timeout for active connections
• Proper resource cleanup
• Context propagation throughout server lifecycle

Zerolog Logging

zerolog.SetGlobalLevel(zerolog.TraceLevel)
log.Logger = log.Output(zerolog.ConsoleWriter{Out: os.Stderr})

Benefits:

• High performance
• Structured logging
• Trace level detail
• Color output

Versioned API

router.Route("/api/v1", func(r chi.Router) {
    // v1 endpoints
})

Benefits:

• Backward compatibility
• Clear versioning
• Easy migration
• Parallel versions

🔍 Troubleshooting

Port Already in Use

# Find and kill process using port 8080
kill -TERM $(lsof -ti :8080)

Server Not Responding

# Check if running
curl -s http://localhost:8080/api/health

# Restart server
pkill -f "go"
go run cmd/server/main.go &

Dependency Issues

# Clean and rebuild
go mod tidy
go build ./...

Tests Failing

# Run with verbose output
go test -v ./...

# Check specific test
go test ./pkg/greet/ -run TestName

📚 Code Examples

Adding New API Endpoint

// 1. Add to interface
func (h *apiV1GreetHandler) RegisterRoutes(router chi.Router) {
    router.Get("/", h.handleGreetQuery)
    router.Get("/{name}", h.handleGreetPath)
    router.Post("/custom", h.handleCustomGreet) // New endpoint
}

// 2. Implement handler
func (h *apiV1GreetHandler) handleCustomGreet(w http.ResponseWriter, r *http.Request) {
    // Parse request
    // Call service
    // Return JSON response
}

Adding Logging

// Trace level logging
log.Trace().Ctx(ctx).Str("key", "value").Msg("message")

// Info level
log.Info().Msg("Important event")

// Error level
log.Error().Err(err).Msg("Error occurred")

Using Context

// Pass context through calls
func handler(w http.ResponseWriter, r *http.Request) {
    result := service.Greet(r.Context(), "John")
    // ...
}

// Create context with values
ctx := context.WithValue(r.Context(), "key", "value")

// Create context with timeout
ctx, cancel := context.WithTimeout(r.Context(), 5*time.Second)
defer cancel()

🎓 Best Practices

Code Organization

• Keep handlers thin, move logic to services
• Use interfaces for dependencies
• Separate route registration from handlers
• Group related functionality

Error Handling

• Return proper HTTP status codes
• Log errors with context
• Don't expose internal errors to clients
• Use structured error responses

Performance

• Use Zerolog's Trace level sparingly in production
• Avoid allocations in hot paths
• Use context timeouts for external calls
• Batch database operations

Testing

• Test interfaces, not implementations
• Use table-driven tests
• Test error cases
• Mock dependencies

📈 Future Enhancements

Potential Features

• Configuration management
• Database integration
• Authentication/Authorization
• Rate limiting
• Metrics and monitoring
• Docker containerization
• CI/CD pipeline

Architectural Improvements

• Request validation middleware
• OpenAPI/Swagger documentation
• Graceful shutdown
• Configuration hot reload
• Circuit breakers

📝 Changelog

2026-04-03 - Current Version

• ✅ Zerolog integration with Trace level
• ✅ Context-aware Greet service
• ✅ Fixed route structure /api/v1/greet/*
• ✅ Comprehensive server management guide
• ✅ Verified all API endpoints working
• ✅ Updated documentation

2026-04-02 - Web API Implementation

• ✅ Chi router integration
• ✅ Versioned API endpoints
• ✅ JSON responses
• ✅ Health endpoint
• ✅ Interface-based design

2026-04-01 - Foundation

• ✅ Go 1.26.1 setup
• ✅ Project structure
• ✅ Core Greet service
• ✅ CLI interface
• ✅ Unit tests

🤖 AI Agent Information

Agent: Mistral Vibe CLI Agent Version: devstral-2 Role: Development Assistant Capabilities:

• Code generation and refactoring
• Test creation
• Documentation
• Architecture guidance
• Best practices enforcement

📋 Quick Reference

Common Commands

# Start server
go run cmd/server/main.go &

# Test API
curl http://localhost:8080/api/v1/greet/John

# Run tests
go test ./...

# Stop server
pkill -f "go"

# CLI usage
go run ./cmd/greet John

Project Structure

cmd/        # Entry points
pkg/        # Core logic
  greet/    # Domain services
  server/   # HTTP server
go.mod      # Dependencies
README.md   # User docs
AGENTS.md   # This file

Key Interfaces

type Greeter interface {
    Greet(ctx context.Context, name string) string
}

type ApiV1Greet interface {
    RegisterRoutes(router chi.Router)
}

📞 Support

For issues or questions:

1. Check this documentation
2. Review test cases
3. Examine existing implementations
4. Consult Go and Chi documentation
5. Ask the AI agent for guidance

This documentation provides a complete guide to developing, testing, and maintaining the DanceLessonsCoach project using the established patterns and best practices.