Initial Commit

main.go

@@ -0,0 +1,135 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"log"
+	"net/http"
+	"os"
+	"os/signal"
+	"strconv"
+	"sync"
+	"syscall"
+	"time"
+)
+
+type AppConfig struct {
+	Addr            string
+	BadgerDir       string
+	PageSize        int
+	ShutdownTimeout time.Duration
+}
+
+func main() {
+	logger := log.New(os.Stdout, "", log.LstdFlags|log.LUTC)
+	if err := run(logger); err != nil {
+		logger.Printf("server error: %v", err)
+		os.Exit(1)
+	}
+}
+
+func run(logger *log.Logger) error {
+	cfg := loadConfig()
+
+	if err := os.MkdirAll(cfg.BadgerDir, 0o755); err != nil {
+		return err
+	}
+
+	store, err := OpenStore(cfg.BadgerDir)
+	if err != nil {
+		return err
+	}
+
+	var closeOnce sync.Once
+	closeStore := func() {
+		if err := store.Close(); err != nil {
+			logger.Printf("close store: %v", err)
+		}
+	}
+	defer closeOnce.Do(closeStore)
+
+	app, err := NewApp(store, cfg.PageSize)
+	if err != nil {
+		return err
+	}
+
+	server := &http.Server{
+		Addr:              cfg.Addr,
+		Handler:           app.Routes(),
+		ReadHeaderTimeout: 5 * time.Second,
+		ReadTimeout:       15 * time.Second,
+		WriteTimeout:      30 * time.Second,
+		IdleTimeout:       60 * time.Second,
+	}
+
+	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
+	defer stop()
+
+	go func() {
+		<-ctx.Done()
+		logger.Printf("shutdown signal received")
+
+		shutdownCtx, cancel := context.WithTimeout(context.Background(), cfg.ShutdownTimeout)
+		defer cancel()
+
+		if err := server.Shutdown(shutdownCtx); err != nil {
+			logger.Printf("http shutdown: %v", err)
+		}
+
+		closeOnce.Do(closeStore)
+	}()
+
+	logger.Printf("listening on %s", cfg.Addr)
+	err = server.ListenAndServe()
+	closeOnce.Do(closeStore)
+	if err != nil && !errors.Is(err, http.ErrServerClosed) {
+		return err
+	}
+
+	return nil
+}
+
+func loadConfig() AppConfig {
+	return AppConfig{
+		Addr:            envOrDefault("APP_ADDR", ":8080"),
+		BadgerDir:       envOrDefault("BADGER_DIR", "data/badger"),
+		PageSize:        envIntOrDefault("PAGE_SIZE", 50),
+		ShutdownTimeout: envDurationOrDefault("SHUTDOWN_TIMEOUT", 10*time.Second),
+	}
+}
+
+func envOrDefault(key, fallback string) string {
+	if value := os.Getenv(key); value != "" {
+		return value
+	}
+
+	return fallback
+}
+
+func envIntOrDefault(key string, fallback int) int {
+	value := os.Getenv(key)
+	if value == "" {
+		return fallback
+	}
+
+	parsed, err := strconv.Atoi(value)
+	if err != nil || parsed <= 0 {
+		return fallback
+	}
+
+	return parsed
+}
+
+func envDurationOrDefault(key string, fallback time.Duration) time.Duration {
+	value := os.Getenv(key)
+	if value == "" {
+		return fallback
+	}
+
+	parsed, err := time.ParseDuration(value)
+	if err != nil || parsed <= 0 {
+		return fallback
+	}
+
+	return parsed
+}