Preheat oven to 350 degrees. Spray a 9 x 13 pan with cooking spray. In a large bowl, combine cake mix, eggs, oil, and 1 can of crushed pineapple with the juice (or half of a large can) and mix well. Pour into prepared baking pan and bake for 25 - ­30 minutes, or until toothpick inserted in center of cake comes out clean. Cool completely on a wire rack. In a medium sized bowl, fold together whipped topping, box of vanilla pudding, and 1 can crushed pineapple with the juice (or other half of can). Spread over the top of cooled cake.