Electricians advice needed

I have a closet grow room and there was no outlet in the room. My first experiment I used a nearby outlet outside the room and ran an extention cord under the door. That wasn't very stealthy and made me nervous so I then realized that I could take the light apart on the ceiling and wire in an outlet on the ceiling. I have and it works just fine as long as the light switch is in the on position. I actually really like it because it keeps my surge protector cord off the ground. My question is...will this outlet have the same 15amps to use as a typical outlet? Right now im in the veg state on my mother plant and not using much electricity. I will be soon running (4) 4' flourescents ontop of my nursery cabinet and a 400 watt HPS. I have run them for a couple hours to see what the temperature was going to and to make sure the wire wasnt getting hot.

Chances are the light is controlled by a 15 amp breaker, which also has outlets in the room on it. If you did a test run and didn't trip the breaker, then your good. If you have more to add, then can either wing it and see if it trips, or find out what outlets and lights (could be multiple rooms) use that breaker. Add up your amps on your equipment, plus whatever else in on that breaker, and see if it will all be to much for it.
Edit: not an electrician, just know a bit.

Use the largest gauge wire possible. Electricity flows around a conductive wire, not through it. Smaller wires = increased resistance = increased amps on start and "poof" or kick or whatever. You cannot use too large a wire. Use the shortest length of wire possible for the same reason. A 15-amp breaker should be sufficient for anything you can run in a closet.

Appreciate the input guys!!

you should just find out whats on the circuit with the light n make shur you dont run anything that pulls to much apms when your running your lights and you should be fine