Better session lock management

handlers/delete_instance.go

@@ -13,6 +13,8 @@ func DeleteInstance(rw http.ResponseWriter, req *http.Request) {
 	instanceName := vars["instanceName"]
 
 	s := services.GetSession(sessionId)
+	s.Lock()
+	defer s.Unlock()
 	i := services.GetInstance(s, instanceName)
 	err := services.DeleteInstance(s, i)
 	if err != nil {

handlers/new_instance.go

@@ -16,14 +16,13 @@ func NewInstance(rw http.ResponseWriter, req *http.Request) {
 	s := services.GetSession(sessionId)
 
 	s.Lock()
+	defer s.Unlock()
 	if len(s.Instances) >= 5 {
-		s.Unlock()
 		rw.WriteHeader(http.StatusConflict)
 		return
 	}
 
 	i, err := services.NewInstance(s)
-	s.Unlock()
 	if err != nil {
 		log.Println(err)
 		//TODO: Set a status error