to Config struct for configging

main.go

@@ -1,19 +1,46 @@
 package main
 
 import (
+	"context"
 	"fmt"
 	"net/http"
-	"os"
+	"os/signal"
+	"syscall"
 )
 
 func main() {
-	p := os.Getenv("PORT")
-	if p == "" {
-		p = "8080"
-	}
-	addr := fmt.Sprintf(":%s", p)
+	ctx, can := signal.NotifyContext(context.Background(), syscall.SIGINT)
+	defer can()
 
-	if err := http.ListenAndServe(addr, http.HandlerFunc(http.NotFound)); err != nil {
+	cfg, err := newConfig()
+	if err != nil {
+		panic(err)
+	}
+
+	if err := run(ctx, cfg); err != nil && ctx.Err() == nil {
 		panic(err)
 	}
 }
+
+func run(ctx context.Context, cfg Config) error {
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	case err := <-listenAndServe(ctx, cfg):
+		return err
+	}
+}
+
+func listenAndServe(ctx context.Context, cfg Config) chan error {
+	s := http.Server{
+		Addr: fmt.Sprintf(":%d", cfg.Port),
+	}
+
+	errc := make(chan error)
+	go func() {
+		defer close(errc)
+		errc <- s.ListenAndServe()
+	}()
+
+	return errc
+}