Initial scaffold with per-nameserver DNS monitoring model

Full project structure following upaas conventions: uber/fx DI, go-chi
routing, slog logging, Viper config. State persisted as JSON file with
per-nameserver record tracking for inconsistency detection. Stub
implementations for resolver, portcheck, tlscheck, and watcher.

internal/server/routes.go

@@ -0,0 +1,43 @@
+package server
+
+import (
+	"time"
+
+	"github.com/go-chi/chi/v5"
+	chimw "github.com/go-chi/chi/v5/middleware"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+)
+
+// requestTimeout is the maximum duration for handling a request.
+const requestTimeout = 60 * time.Second
+
+// SetupRoutes configures all HTTP routes.
+func (s *Server) SetupRoutes() {
+	s.router = chi.NewRouter()
+
+	// Global middleware
+	s.router.Use(chimw.Recoverer)
+	s.router.Use(chimw.RequestID)
+	s.router.Use(s.mw.Logging())
+	s.router.Use(s.mw.CORS())
+	s.router.Use(chimw.Timeout(requestTimeout))
+
+	// Health check
+	s.router.Get("/health", s.handlers.HandleHealthCheck())
+
+	// API v1 routes
+	s.router.Route("/api/v1", func(r chi.Router) {
+		r.Get("/status", s.handlers.HandleStatus())
+	})
+
+	// Metrics endpoint (optional, with basic auth)
+	if s.params.Config.MetricsUsername != "" {
+		s.router.Group(func(r chi.Router) {
+			r.Use(s.mw.MetricsAuth())
+			r.Get(
+				"/metrics",
+				promhttp.Handler().ServeHTTP,
+			)
+		})
+	}
+}

internal/server/server.go

@@ -0,0 +1,129 @@
+// Package server provides the HTTP server.
+package server
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"log/slog"
+	"net/http"
+	"time"
+
+	"github.com/go-chi/chi/v5"
+	"go.uber.org/fx"
+
+	"sneak.berlin/go/dnswatcher/internal/config"
+	"sneak.berlin/go/dnswatcher/internal/globals"
+	"sneak.berlin/go/dnswatcher/internal/handlers"
+	"sneak.berlin/go/dnswatcher/internal/logger"
+	"sneak.berlin/go/dnswatcher/internal/middleware"
+)
+
+// Params contains dependencies for Server.
+type Params struct {
+	fx.In
+
+	Logger     *logger.Logger
+	Globals    *globals.Globals
+	Config     *config.Config
+	Middleware *middleware.Middleware
+	Handlers   *handlers.Handlers
+}
+
+// shutdownTimeout is how long to wait for graceful shutdown.
+const shutdownTimeout = 30 * time.Second
+
+// readHeaderTimeout is the max duration for reading request headers.
+const readHeaderTimeout = 10 * time.Second
+
+// Server is the HTTP server.
+type Server struct {
+	startupTime time.Time
+	port        int
+	log         *slog.Logger
+	router      *chi.Mux
+	httpServer  *http.Server
+	params      Params
+	mw          *middleware.Middleware
+	handlers    *handlers.Handlers
+}
+
+// New creates a new Server instance.
+func New(
+	lifecycle fx.Lifecycle,
+	params Params,
+) (*Server, error) {
+	srv := &Server{
+		port:     params.Config.Port,
+		log:      params.Logger.Get(),
+		params:   params,
+		mw:       params.Middleware,
+		handlers: params.Handlers,
+	}
+
+	lifecycle.Append(fx.Hook{
+		OnStart: func(_ context.Context) error {
+			srv.startupTime = time.Now()
+			go srv.Run()
+
+			return nil
+		},
+		OnStop: func(ctx context.Context) error {
+			return srv.Shutdown(ctx)
+		},
+	})
+
+	return srv, nil
+}
+
+// Run starts the HTTP server.
+func (s *Server) Run() {
+	s.SetupRoutes()
+
+	listenAddr := fmt.Sprintf(":%d", s.port)
+	s.httpServer = &http.Server{
+		Addr:              listenAddr,
+		Handler:           s,
+		ReadHeaderTimeout: readHeaderTimeout,
+	}
+
+	s.log.Info("http server starting", "addr", listenAddr)
+
+	err := s.httpServer.ListenAndServe()
+	if err != nil && !errors.Is(err, http.ErrServerClosed) {
+		s.log.Error("http server error", "error", err)
+	}
+}
+
+// Shutdown gracefully shuts down the server.
+func (s *Server) Shutdown(ctx context.Context) error {
+	if s.httpServer == nil {
+		return nil
+	}
+
+	s.log.Info("shutting down http server")
+
+	shutdownCtx, cancel := context.WithTimeout(
+		ctx, shutdownTimeout,
+	)
+	defer cancel()
+
+	err := s.httpServer.Shutdown(shutdownCtx)
+	if err != nil {
+		s.log.Error("http server shutdown error", "error", err)
+
+		return fmt.Errorf("shutting down http server: %w", err)
+	}
+
+	s.log.Info("http server stopped")
+
+	return nil
+}
+
+// ServeHTTP implements http.Handler.
+func (s *Server) ServeHTTP(
+	writer http.ResponseWriter,
+	request *http.Request,
+) {
+	s.router.ServeHTTP(writer, request)
+}