It's really similar to an egg roll, but it also also served uncooked sometimes, in a soft translucent rice wrapper.

Sweet chili sauce can be purchased at most grocery stores, like walmart, or an any asian market, and it's usually pretty cheap. I think I pay about 3 bucks a bottle.

Here's an example of the sauce (leads to a 6 pack of the sauce on Amazon):

https://www.amazon.com/Thai-Kitchen-Sweet-Dipping-6-57-Ounce/dp/B0072DGTFS/ref=sr_1_11_a_it?ie=UTF8&qid=1470257748&sr=8-11&keywords=sweet+chili+sauce