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Best way to check if ROS is running

asked 2011-07-06 11:59:32 -0500

baalexander gravatar image

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.

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answered 2011-07-06 15:49:18 -0500

Nash gravatar image

updated 2011-07-06 16:07:52 -0500

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.

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Thanks @Nash. `rostopic list ` does print out an error if roscore is not running, which I can use to check if ROS is running. However, it seems a bit hackish still.
baalexander gravatar image baalexander  ( 2011-07-07 14:27:16 -0500 )edit

@Nash thx this works with rostopic python API. My example can be seen here.

130s gravatar image 130s  ( 2013-05-05 11:25:55 -0500 )edit

answered 2015-08-11 03:44:43 -0500

updated 2015-08-11 03:45:12 -0500

In C++ you can check for the master being online, returns true if up, false if not.

#include <ros/master.h>
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answered 2015-08-10 18:47:59 -0500

130s gravatar image

Found this sample in rostopic. This looks more essential API-wise.

except socket.error:
    raise ROSTopicIOException("Unable to communicate with master!")
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Could this be also used to check if a node is running by specifying the /rostopic ?

MarviB16 gravatar image MarviB16  ( 2019-06-11 06:31:45 -0500 )edit

answered 2018-06-26 15:38:39 -0500

murali1842 gravatar image

updated 2018-11-28 19:15:51 -0500

jayess gravatar image

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'
    print 'ROS MASTER is Offline'
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Can you please provide an explanation to go along with your code? Code with an explanation is much more valuable than code alone.

jayess gravatar image jayess  ( 2018-11-27 19:01:33 -0500 )edit

answered 2011-07-06 20:16:27 -0500

Ugo gravatar image

You could also use part of this answer: the following line checks periodically if ros is started.

until rostopic list ; do sleep 1; done
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answered 2018-08-26 16:30:07 -0500

gonzalocasas gravatar image

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.

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answered 2015-08-10 19:31:33 -0500

nnnnnnils gravatar image

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?'

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how to check that programmatically

james P M gravatar image james P M  ( 2021-10-12 01:15:00 -0500 )edit

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Asked: 2011-07-06 11:59:32 -0500

Seen: 19,740 times

Last updated: Nov 28 '18