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How can two identical nodelets in one process remap topics and services?

asked 2011-02-15 10:43:30 -0500

joq gravatar image

updated 2011-02-16 00:31:19 -0500

I want to run a stereo pair of 1394 cameras as nodelets. It would be good to run both in the same address space with stereo_image_proc. But, I can't figure out how to remap the topic and service names to do that.

With nodes, I can get the right topic and service names like this:

<launch>
 <group ns="stereo" >

   <!-- left camera -->
   <node pkg="camera1394" type="camera1394_node" name="left_node" >
     <rosparam file="$(find camera1394)/tests/left.yaml" />
     <remap from="camera" to="left" />
   </node>

   <!-- right camera -->
   <node pkg="camera1394" type="camera1394_node" name="right_node" >
     <rosparam file="$(find camera1394)/tests/right.yaml" />
     <remap from="camera" to="right" />
   </node>

 </group>
</launch>

The equivalent nodelet launch script does not work:

<launch>
 <group ns="stereo" >

   <!-- nodelet manager process -->
   <node pkg="nodelet" type="nodelet" name="camera_nodelet_manager"
         args="manager" />

   <!-- left camera -->
   <node pkg="nodelet" type="nodelet" name="left_camera"
         args="load camera1394/driver camera_nodelet_manager" >
     <rosparam file="$(find camera1394)/tests/left.yaml" />
     <remap from="camera" to="left" />
   </node>

   <!-- right camera -->
  <node pkg="nodelet" type="nodelet" name="right_camera"
        args="load camera1394/driver camera_nodelet_manager" >
     <rosparam file="$(find camera1394)/tests/right.yaml" />
     <remap from="camera" to="right" />
  </node>

 </group>
</launch>

The failure is that neither <remap> works and both nodelets try to declare the same service names: /stereo/camera/set_camera_info, /stereo/camera/image_raw/compressed/set_parameters, etc..

It seems that the <remap> has to be applied to the nodelet manager node, not the nodes doing the load.

So, how do I remap camera-->left for one nodelet and camera-->right for the other?

Or, is there some other way to solve this problem?

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1 Answer

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answered 2011-02-16 07:43:06 -0500

tfoote gravatar image

Nodelets are supposed to work exactly as nodes do. This looks like a bug in the interaction between roscpp and nodelets. I've filed a ticket: https://code.ros.org/trac/ros-pkg/ticket/4794

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Comments

I agree that it **should** work that way. I had not noticed that it does work when not using subordinate names. Let's discuss what to do using ticket #4794.
joq gravatar imagejoq ( 2011-02-16 13:40:00 -0500 )edit

have been this bug solved?

marilia15 gravatar imagemarilia15 ( 2014-03-28 01:42:44 -0500 )edit

It was fixed 3 years ago in ROS Diamondback.

joq gravatar imagejoq ( 2014-03-28 07:27:15 -0500 )edit

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Asked: 2011-02-15 10:43:30 -0500

Seen: 1,259 times

Last updated: Mar 28 '14