Whether its against the spirit of the constitution depends on how you perceive the nature of monitoring. The "spirit" of the 4th amendment is to keep the police from invading your personal space. If you think of your gdrive as a natural extension of your desk drawer, then I can see how you could interpret it as against the spirit, because the NSA looking through those documents is like the police rummaging through your desk.

That's not the only way to view the situation, though. That's the "software" view of the world. I take a "hardware" view of the world. That data is sitting on Google's property. Its servers, its hard drives. You've given up posession of that data. Under that view, rummaging through that data is neither unconstitutional nor against the spirit thereof.

more generally, the constitution just has nothing to say about the larger issue of "tracking." The founders wrote the 4th with a specific grievance in mind: British searches of houses with very broad warrants. They just didn't address the government collecting information you left out in the world to track you.