ncro: wire all components; handle shutdown more gracefully

Signed-off-by: NotAShelf <raf@notashelf.dev>
Change-Id: I81fab7fa2cfa5a109b8b317fa53f10d86a6a6964

cmd/ncro/main.go

@@ -1,14 +1,113 @@
 package main
 
 import (
+	"context"
+	"flag"
 	"log/slog"
+	"net/http"
 	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	"notashelf.dev/ncro/internal/cache"
+	"notashelf.dev/ncro/internal/config"
+	"notashelf.dev/ncro/internal/prober"
+	"notashelf.dev/ncro/internal/router"
+	"notashelf.dev/ncro/internal/server"
 )
 
 func main() {
-	slog.SetDefault(slog.New(slog.NewJSONHandler(os.Stdout, &slog.HandlerOptions{
+	configPath := flag.String("config", "", "path to config YAML file")
-		Level: slog.LevelInfo,
+	flag.Parse()
-	})))
+
-	slog.Info("ncro starting")
+	cfg, err := config.Load(*configPath)
-	os.Exit(0)
+	if err != nil {
+		slog.Error("failed to load config", "error", err)
+		os.Exit(1)
+	}
+
+	level := slog.LevelInfo
+	switch cfg.Logging.Level {
+	case "debug":
+		level = slog.LevelDebug
+	case "warn":
+		level = slog.LevelWarn
+	case "error":
+		level = slog.LevelError
+	}
+	var handler slog.Handler
+	if cfg.Logging.Format == "text" {
+		handler = slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{Level: level})
+	} else {
+		handler = slog.NewJSONHandler(os.Stdout, &slog.HandlerOptions{Level: level})
+	}
+	slog.SetDefault(slog.New(handler))
+
+	db, err := cache.Open(cfg.Cache.DBPath, cfg.Cache.MaxEntries)
+	if err != nil {
+		slog.Error("failed to open database", "path", cfg.Cache.DBPath, "error", err)
+		os.Exit(1)
+	}
+	defer db.Close()
+
+	expireDone := make(chan struct{})
+	go func() {
+		ticker := time.NewTicker(5 * time.Minute)
+		defer ticker.Stop()
+		for {
+			select {
+			case <-expireDone:
+				return
+			case <-ticker.C:
+				if err := db.ExpireOldRoutes(); err != nil {
+					slog.Warn("expire routes error", "error", err)
+				}
+			}
+		}
+	}()
+
+	p := prober.New(cfg.Cache.LatencyAlpha)
+	upstreamURLs := make([]string, len(cfg.Upstreams))
+	for i, u := range cfg.Upstreams {
+		upstreamURLs[i] = u.URL
+	}
+	p.InitUpstreams(upstreamURLs)
+	for _, u := range upstreamURLs {
+		go p.ProbeUpstream(u)
+	}
+
+	probeDone := make(chan struct{})
+	go p.RunProbeLoop(30*time.Second, probeDone)
+
+	r := router.New(db, p, cfg.Cache.TTL.Duration, 5*time.Second)
+	srv := &http.Server{
+		Addr:         cfg.Server.Listen,
+		Handler:      server.New(r, p, cfg.Upstreams),
+		ReadTimeout:  cfg.Server.ReadTimeout.Duration,
+		WriteTimeout: cfg.Server.WriteTimeout.Duration,
+	}
+
+	stop := make(chan os.Signal, 1)
+	signal.Notify(stop, syscall.SIGINT, syscall.SIGTERM)
+
+	go func() {
+		slog.Info("ncro listening", "addr", cfg.Server.Listen, "upstreams", len(cfg.Upstreams))
+		if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
+			slog.Error("server error", "error", err)
+			os.Exit(1)
+		}
+	}()
+
+	<-stop
+	slog.Info("shutting down")
+
+	close(expireDone)
+	close(probeDone)
+
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+	if err := srv.Shutdown(ctx); err != nil {
+		slog.Error("shutdown error", "error", err)
+	}
 }