Start a node from python code - rospy equivalence rosrun - rosgui qt

edit

As of now the internal roslaunch python API is unstable, but that doesn't mean you can't use it, it just means that there's no guarantee your code is going to continue to work.

Stu Glaser wrote a simple qt-based roslaunch frontend which can be found here: https://kforge.ros.org/rxlaunch/hg/file/9456528dd14c/rxlaunch.py and this gives a simple example of how to do what roslaunch does via Python. (it also has some code taken from roslaunch itself)

If you want to start a node from Python, and want to be able to expect that it will continue to work, you could call out to rosrun with the Python subprocess module

Also, "rosrun" is just a bash script.

Not entirely sure what you mean but I assume you've already checked rospy.init_node?

Just use Popen:

import shlex
from psutil import Popen
# start
node_process = Popen(
    shlex.split('rosrun foo bar')
)
# stop
node_process.terminate()