I am using the roslaunch Python API to run some launch files. Some of these launch files have some arguments (specified with the arg tag). On the terminal, I would set these arguments like this:
roslaunch mypkg foobar.launch bla:=42
Unfortunately I am not able to figure out how to set the argument (bla:=42) when running the same launch file with the Python API.
Originally posted by Felix Widmaier on ROS Answers with karma: 382 on 2017-10-02
Post score: 0
Hello,
After digging for a while, I believe it's not possible to set the arguments using the API.
There are related questions in this forum and seems that the users are using python subprocess to do that:
https://answers.ros.org/question/198910/how-to-set-args-with-python-roslaunch/ https://answers.ros.org/question/265796/parameters-roslaunch-from-python-script/
There's a page in ROS wiki as example, but without arguments: http://wiki.ros.org/roslaunch/API%20Usage
If you want to check by yourself, here goes the API page that refers to the launch object used in a ROS wiki:
http://docs.ros.org/indigo/api/roslaunch/html/roslaunch.parent.ROSLaunchParent-class.html
Fortunately, there's a Pull Request that proposes a solution to that issue:
https://github.com/ros/ros_comm/pull/1115
I hope it can help you!
Originally posted by marcoarruda with karma: 541 on 2017-10-02
This answer was ACCEPTED on the original site
Post score: 3
Comment by Felix Widmaier on 2017-10-04:
Thanks for linking the pull request, I did not find that one.
Comment by Felix Widmaier on 2018-05-30:
Update: The linked pull request is merged for lunar (not backported to previous versions, though)
As marcoarruda already wrote, there does not seem to be an option for this in the current API.
I checked the code of the roslaunch executable and found out, that they directly read the values from sys.argv. So a not very nice but working hack is to add arguments there before using roslaunch:
sys.argv.append("bla:=42")
Originally posted by Felix Widmaier with karma: 382 on 2017-10-04
This answer was NOT ACCEPTED on the original site
Post score: 2