电报漫游器在一段时间后停止投放

I uploaded a simple telegram bot to google-aplication-engine. And after uploading it works as expected some time. Then it stoped respond to request from telegram. The bot is very simple

func main() {
    bot, err := tba.NewBotAPI("apitockenhere")
    ...
    for {
        select {
        case update := <-uchan:
        ...
    }
}

If I open web application in browser (it doesnot contais any handlers) then telegram bot again starts working some time and then stops.

How to modify the code to prevent it from stopping?