level.go

//program startup
routerList      *storage.RouterList   
   
r.routerList.Conn, err = leveldb.Open("level", nil)
if err != nil {
  log.Fatal(err)
}

type RouterList struct {
	Records []Router
    Conn    *leveldb.DB
}

//storage.go
func (d *RouterList) AddRouter(macAddr uint64, routerConfig []byte) {
	key := make([]byte, 8)
	binary.LittleEndian.PutUint64(key, macAddr)
	log.Printf("set %X", key)
    err := d.Conn.Set(key, routerConfig, nil)
	if err != nil {
		log.Printf("set", err)
	}
}

func (d *RouterList) GetRouter(routerId uint64) (Router, error) {
	key := make([]byte, 8)
	binary.LittleEndian.PutUint64(key, routerId)
	log.Printf("get %X", key)
	data, err := d.Conn.Get(key, nil)
	if err != nil {
		log.Print(err)
	}
	router := Router{}
	if err := binary.Read(bytes.NewReader(data), binary.LittleEndian, &router); err != nil {
		log.Print("Cannot binary read router config")
		return router, err
	}
	return router, nil
}