CUB-112: scaffold Go backend with Chi, pgx, health check

backend/internal/handlers/health.go

@@ -0,0 +1,50 @@
+package handlers
+
+import (
+	"context"
+	"encoding/json"
+	"log/slog"
+	"net/http"
+	"time"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+)
+
+// HealthHandler provides a health check endpoint that verifies database connectivity.
+type HealthHandler struct {
+	dbPool *pgxpool.Pool
+}
+
+// NewHealthHandler creates a new HealthHandler with the given database pool.
+func NewHealthHandler(dbPool *pgxpool.Pool) *HealthHandler {
+	return &HealthHandler{dbPool: dbPool}
+}
+
+// ServeHTTP handles GET /health requests.
+func (h *HealthHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	ctx, cancel := context.WithTimeout(r.Context(), 5*time.Second)
+	defer cancel()
+
+	dbConnected := false
+	if h.dbPool != nil {
+		if err := h.dbPool.Ping(ctx); err == nil {
+			dbConnected = true
+		} else {
+			slog.Warn("health check db ping failed", "error", err)
+		}
+	}
+
+	resp := map[string]any{
+		"status":       "ok",
+		"timestamp":    time.Now().UTC().Format(time.RFC3339),
+		"db_connected": dbConnected,
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	if !dbConnected {
+		w.WriteHeader(http.StatusServiceUnavailable)
+	}
+	if err := json.NewEncoder(w).Encode(resp); err != nil {
+		slog.Error("failed to encode health response", "error", err)
+	}
+}