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rosgraph unable to get node information in Fuerte

asked 2012-04-28 12:04:08 -0500

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In Fuerte, rosgraph, rxgraph and roswtf do not work correctly for me. This error can be reproduced by running the following commands:

rosrun roscpp_tutorials talker
rosrun roscpp_tutorials listener

The nodes are definitely connected, as I can see the output from both the nodes. Additionally rostopic hz and rostopic echo can successfully subscribe to these messages. rosgraph is unable to determine the node connectivity, and gives the following output:

  /listener :
  /talker :
  /rosout :

Similarly, rxgraph does not show this connectivity either, and the output can be seen in this screenshot. Note that the information for the listener node in the rxgraph sidebar seems correct. The sidebar information for the talker node can be seen in screenshot-talker.

roswtf seems to alternate randomly between:

Found 1 error(s).

ERROR Communication with [/talker] raised an error:


Found 4 error(s).

ERROR Communication with [/talker] raised an error: 
ERROR Communication with [/listener] raised an error: 
ERROR Communication with [/rosout] raised an error: 
ERROR The following nodes should be connected but aren't:
 * /talker->/rosout (/rosout)
 * /listener->/rosout (/rosout)
 * /talker->/listener (/chatter)

I suspect the error to be somewhere in the rosgraph API. Any thoughts would be appreciated.

Thanks! Piyush

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answered 2012-05-01 10:51:29 -0500

updated 2012-05-01 15:28:07 -0500

This problem was attributed to 2 separate bugs in the rosgraph python scripts, that have been reported in 2 separate tickets (ticket 3946 and ticket 3947). Patches to fix the problem are included in both tickets.

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Asked: 2012-04-28 12:04:08 -0500

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Last updated: May 01 '12