cmd/pkgserver: gracefully shut down on signal

Signed-off-by: Ophestra <cat@gensokyo.uk>

cmd/pkgserver/main.go

@@ -8,6 +8,7 @@ import (
 	"os"
 	"os/signal"
 	"syscall"
+	"time"
 
 	"hakurei.app/command"
 	"hakurei.app/container/check"
@@ -16,7 +17,8 @@ import (
 	"hakurei.app/message"
 )
 
-//go:generate sh -c "sass ui/static/dark.scss ui/static/dark.css && sass ui/static/light.scss ui/static/light.css && tsc -p ui/static"
+const shutdownTimeout = 15 * time.Second
+
 func main() {
 	log.SetFlags(0)
 	log.SetPrefix("pkgserver: ")
@@ -65,9 +67,23 @@ func main() {
 		if err := index.populate(cache, report); err != nil {
 			return err
 		}
-		uiRoutes(http.DefaultServeMux)
-		apiRoutes(http.DefaultServeMux, &index)
-		return http.ListenAndServe(flagAddr, nil)
+
+		var mux http.ServeMux
+		uiRoutes(&mux)
+		apiRoutes(&mux, &index)
+		server := http.Server{
+			Addr:    flagAddr,
+			Handler: &mux,
+		}
+		go func() {
+			<-ctx.Done()
+			c, cancel := context.WithTimeout(context.Background(), shutdownTimeout)
+			defer cancel()
+			if err := server.Shutdown(c); err != nil {
+				log.Fatal(err)
+			}
+		}()
+		return server.ListenAndServe()
 	}).Flag(
 		&flagBaseDir,
 		"b", command.StringFlag(""),
@@ -77,8 +93,10 @@ func main() {
 		"addr", command.StringFlag(":8067"),
 		"TCP network address to listen on",
 	)
-	c.MustParse(os.Args[1:], func(e error) {
-		log.Fatal(e)
-	})
-
+	c.MustParse(os.Args[1:], func(err error) {
+		if errors.Is(err, http.ErrServerClosed) {
+			os.Exit(0)
+		}
+		log.Fatal(err)
+	})
 }

cmd/pkgserver/ui.go

@@ -5,6 +5,7 @@ import (
 	"net/http"
 )
 
+//go:generate sh -c "sass ui/static/dark.scss ui/static/dark.css && sass ui/static/light.scss ui/static/light.css && tsc -p ui/static"
 //go:embed ui/*
 var content embed.FS