F1 has announced there will be a GP in Hanoi in 2020 on a street circuit with a newly built pit and paddock area, some of the track has yet to be built and will become public road outside of racing. It is to be financed from private/business sources.
http://classic.autosport.com/news/report.php/id/139883
There was no mention of what part of the season it will happen but I do recall Chase Carey saying that he would like to see the Asian part of the season in the early part of the year.
It will be interesting to see what sort of live audience they get when compared with some of the GP's Bernie brought in.