How to exit a ROS node on keyboard interrupt?

edit

How do you write a Python ROS node so that it exits in response to a KeyboardInterrupt exception?

I have a trivial node like:

class MyNode:

    def __init__(self):
        while 1:
            do stuff

if __name__ == '__main__':
    rospy.init_node('mynode')
    MyNode(rospy.get_name())

But pressing ^C doesn't stop it. I see my "^C" interrupt character appear in the output of my "do stuff" code, but the node continues to run, almost as though it's not running in the main thread.

I tried implementing a rospy.on_shutdown() callback, but it's never called in response to a KeyboardInterrupt.