# Code Examples

Snippets and patterns used across the `dance-lessons-coach` codebase. Extracted from the original `AGENTS.md` (Tâche 6 restructure).

## Adding a New API Endpoint

```go
// 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
}
```

## Logging with Zerolog

```go
// 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")
```

For the full logging strategy (when to use Trace vs Info, performance considerations), see [ADR-0003 — Zerolog Logging](../adr/0003-zerolog-logging.md).

## Using `context.Context`

```go
// 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()
```

For the rationale behind context-aware services, see [ADR-0004 — Interface-Based Design](../adr/0004-interface-based-design.md).

## Best Practices Reminders

For higher-level guidance on code organization, error handling, performance, and testing, see [`AGENT_USAGE_GUIDE.md`](AGENT_USAGE_GUIDE.md#best-practices) section "Best Practices".