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I am writing a script, which relies on ROS currently running. I would like to check if ROS is currently running on the script's machine. What's the best way to do this?
A couple ways I am considering are pinging Master URI and checking the processes. However, I'm asking to see if there's a better way. Perhaps an environment variable is set.
If you want to do it in a script, run a regex over the output of "rostopic list" for "/rosout." If its not in the output then the roscore is not running.
@Nash thx this works with rostopic python API. My example can be seen here.
In C++ you can check for the master being online, returns true if up, false if not.
#include <ros/master.h>
...
ros::master::check();
Found this sample in rostopic. This looks more essential API-wise.
try:
rosgraph.Master('/rostopic').getPid()
except socket.error:
raise ROSTopicIOException("Unable to communicate with master!")
Gives out a boolean if the master uri is online or not
import rosgraph
if rosgraph.is_master_online(): # Checks the master uri and results boolean (True or False)
print 'ROS MASTER is Online'
else:
print 'ROS MASTER is Offline'
You could also use part of this answer: the following line checks periodically if ros is started.
until rostopic list ; do sleep 1; done
If you start your script with roslaunch files, the best option might be what ruffsl suggested on this github issue and simply add --wait (e.g. roslaunch --wait robot_plan robot_plan.launch) to it.
Why, "better"? I assume if your script requires ROS to be running, it needs certain ROS services to be available? Why not check if those services are available? I imagine that would better suit your script's question of 'do I have everything I need to run right now?'
Asked: 2011-07-06 11:59:32 -0500
Seen: 21,147 times
Last updated: Nov 28 '18
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