code refactoring, enabled memory db persist to fs.

server/server.go

@@ -1,12 +1,17 @@
 package server
 
 import (
+	"context"
 	"fmt"
 	"io"
 	"io/fs"
 	"log"
 	"net/http"
 	"net/rpc"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
 
 	"github.com/gofiber/fiber/v2"
 	"github.com/gofiber/fiber/v2/middleware/cors"
@@ -18,6 +23,8 @@ import (
 var db MemoryDB
 
 func RunBlocking(port int, frontend fs.FS) {
+	db.Restore()
+
 	service := new(Service)
 	rpc.Register(service)
 
@@ -73,5 +80,34 @@ func RunBlocking(port int, frontend fs.FS) {
 
 	app.Server().StreamRequestBody = true
 
+	go periodicallyPersist()
+	go gracefulShutdown(app)
+
 	log.Fatal(app.Listen(fmt.Sprintf(":%d", port)))
 }
+
+func gracefulShutdown(app *fiber.App) {
+	ctx, stop := signal.NotifyContext(context.Background(),
+		os.Interrupt,
+		syscall.SIGTERM,
+		syscall.SIGQUIT,
+	)
+
+	go func() {
+		<-ctx.Done()
+		log.Println("shutdown signal received")
+
+		defer func() {
+			db.Persist()
+			stop()
+			app.ShutdownWithTimeout(time.Second * 5)
+		}()
+	}()
+}
+
+func periodicallyPersist() {
+	for {
+		db.Persist()
+		time.Sleep(time.Minute * 5)
+	}
+}