Roslaunch can't locate node, but rosrun works fine

I'm working on a simple node written entirely in python. To make it work with roslaunch, I made it into a package. I got the package working fine, and I can run `rosrun my_package controller` just fine. However, when I run it in a roslaunch file, it gives the error ` ERROR: cannot launch node of type [my_package/controller]: can't locate node [controller] in package [my_package]` What is wrong with my environment or package? As a minimal example, I get this with the simple launch file: What I've tried so far: 1. Changing the name of the executable from "controller" to "controller.py" 2. Setting 777 permissions on the executable 3. Relaunching the terminal