[ves]

Your application code shouldn't have sharding concerns in its logic. To achieve this, you should introduce an abstraction layer. One such example is vitess[0], which is used at YouTube.

If that's too much work, then an easy preliminary step is to add the abstraction layer in your application code. That gets you most of the benefits of a proxy for the purpose of having clean application logic, and makes it easy to switch over later, but is less powerful and feature complete.

[0]: http://vitess.io/overview/#features