safe append

internal/interface/swagger/api.2.go

@@ -404,6 +404,7 @@ func (api *API2) PayCart(ctx echo.Context) error {
 
 	sendErrors := make([]errors.Error, 0)
 	waitGroup := sync.WaitGroup{}
+	mutex := sync.Mutex{}
 
 	for _, tariff := range tariffs {
 		waitGroup.Add(1)
@@ -413,6 +414,8 @@ func (api *API2) PayCart(ctx echo.Context) error {
 
 			if err := api.producer.Send(ctx.Request().Context(), userID, &currentTariff); err != nil {
 				api.logger.Error("failed to send tariff on <Send> of <TariffBrokerService>", zap.Error(err))
+				mutex.Lock()
+				defer mutex.Unlock()
 				sendErrors = append(sendErrors, err)
 			}
 		}(tariff)