Expression: So far, so good!

So far means until this moment. So good means that things are going well. So far, so good is an expression which means that everything is going ok until this moment; nothing bad has happened yet and the status is positive.
What's the feeling of this expression? People use it when they want to say that everything is going well but the future is uncertain. Of course, the future is always uncertain, but some people like to emphasize this more than others.
So if someone asks you the status of a new project, for example, you could say "So far, so good" if everthything is going well.