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

asked 2012-08-20 01:54:39 -0500

clotz
71 ●3 ●4 ●6

updated 2018-03-21 12:08:43 -0500

130s

10937 ●203 ●339 ●330 http://www.linkedin.co...

Hallo,

I'm writing a plugin for my rosgui in python. At the moment I'm trying to write an "pressed-button" action which starts a rosnode. I's there a python-command equivalent to "rosrun pkg node" or the launch-command "<node name="..." pkg="..." type="...">?

Unfortunately I couldn't find something in the documentations yet.

Thanks for Help.

edit retag flag offensive close merge delete

add a comment

1

answered 2016-03-12 18:37:29 -0500

Pablo Iñigo Blasco

2982 ●74 ●121 ●128 http://www.linkedin.co...

updated 2020-10-11 22:52:53 -0500

lucasw

8729 ●137 ●239 ●256 https://github.com/lucasw

You can use the roslaunch api for python (ref):

import roslaunch

package = 'rqt_gui'
executable = 'rqt_gui'
node = roslaunch.core.Node(package, executable)

launch = roslaunch.scriptapi.ROSLaunch()
launch.start()

process = launch.launch(node)
print(process.is_alive())
process.stop()

edit flag offensive delete link

Comments

@lucasw any idea how to rewrite this code in ROS2 foxy?

mac137 ( 2021-02-03 18:53:11 -0500 )edit

add a comment

0

answered 2020-02-17 12:29:11 -0500

machinekoder
69 ●12 ●13 ●20

Just use Popen:

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

edit flag offensive delete link

Comments

@machinekodernode_process.terminate() does not actually terminates nodes in ROS2 foxy. After the execution of this line of code, I can still see all the nodes in ros2 node list. Any idea how to fix that?

mac137 ( 2021-02-03 18:59:59 -0500 )edit

add a comment

4

answered 2012-09-08 16:28:23 -0500

jbohren

5799 ●55 ●87 ●102 http://dscl.lcsr.jhu.e...

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.