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How to get type information about running action server? [closed]

asked 2016-11-11 02:38:46 -0500

vivitter gravatar image

Hi, I am new to ROS. I have finished tutorials and I understand how to create simple action server & client.

Next, I would like to know how to get type information about running action server. For example, if you want to send a new goal with an action client, you will write as follows.

client = actionlib.SimpleActionClient('move_base', MoveBaseAction)
goal = MoveBaseGoal()
...Set goal parameter

To write this code, users have to know that "move_base" requires MoveBaseAction and MoveBaseGoal.
Of course, I can learn the dependency from Wiki page. But, are there any other smart way to get these dependency information from running action server?

Thanks a lot for your attention!

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Closed for the following reason the question is answered, right answer was accepted by vivitter
close date 2016-11-11 05:56:01.242318

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answered 2016-11-11 04:37:15 -0500

rbbg gravatar image

updated 2016-11-11 06:48:50 -0500


Currently, as can be read in this question, there is no simple way to list the action servers. Running rostopic list | grep feedback as suggested, you can see the ones that are running. (every action server broadcasts a goal, results, feedback, status and cancel topic)

When the move group is running, rostopic list | grep feedback will return at least:


Then you can use rostopic info to find the type of these topics. for instance: rostopic info /move_group/feedback returns:

Type: moveit_msgs/MoveGroupActionFeedback

As a last step you can run rosmsg show moveit_msgs/MoveGroupAction to get the full message definition (rosmsg show moveit_msgs/MoveGroupActionFeedback will only show the feedback part). As it is the completely expanded tree of the message it is quite long and I won't post it here, but you get the idea.

All in all, I find looking at the message definition in the message definition easier, but this will also work.

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Hi, rbbg. Thank you very much for your help! I am very sorry for the duplicate question.

I think such a demand is very common. I hope more simple API will be released in the future. I will consider how to implement it.

vivitter gravatar image vivitter  ( 2016-11-11 05:55:05 -0500 )edit

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Asked: 2016-11-11 02:38:46 -0500

Seen: 1,933 times

Last updated: Nov 11 '16