It will end when enough people get sick (I read it was something like 60-70%) and herd immunity is developed, or someone creates a vaccine. So realistically several months/ a year. It's gonna take long either way because social isolation stops the disease from spreading and thus herd immunity from developing faster, and vaccines take a long time to develop.
World economy on the other hand can't handle a year long lock down so even if things are bad countries are going to eventually ease on the current restrictions. I just hope people finally learn the value of hand washing and face masks. And corporations realize that sick people should be able to stay at home. Regular flu and influenza kill vulnerable people by the thousands already!