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How should I best add a python node to a cpp package?

asked 2014-04-30 13:18:34 -0500

blakeh gravatar image

I have built a C++ package that integrates with turtle_sim and does some cool stuff. Now I'd like it to communicate (via ros::service) with a new python node. Should I add that in /scripts of the existing package (not working, cmake issues with catkin_make) or make a new package (next to existing package in /src)??



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answered 2014-04-30 20:12:58 -0500

Jacco van der Spek gravatar image

Both can be done. You should be able to just put the Python script in /scripts. Make sure that you advertise your service in the Python script and subscribe to it in your C++ main/class.

If you get catkin_make errrors check if your package.xml and CMakelist.txt both contain rospy as depend package.

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Thank you! This moved me on to the next level of errors. I did not have rospy properly in my dependencies. I added them in CMakelist.txt right next to where roscpp was, (and corrected a typo in package.xml!). catkin_make error message was totally misdirecting so thanks again!

blakeh gravatar image blakeh  ( 2014-05-01 05:46:59 -0500 )edit

OK - on to next question. How do I set up the service in cpp code template which references a python service? The example for cpp client requires a .h file for the service: 2 #include "beginner_tutorials/AddTwoInts.h" 15 ros::ServiceClient client = n.serviceClient<beginner_tutorials::addtwoints>("add_two_ints"); Thanks again!

blakeh gravatar image blakeh  ( 2014-05-01 05:52:09 -0500 )edit

If you're satisfied with the answer, you can accept it.

Jacco van der Spek gravatar image Jacco van der Spek  ( 2014-05-02 03:29:29 -0500 )edit

Actually it's still unresolved. I guess I forked this to a diffferent question where I commented: The key to this turned out to be finding "AddTwoInts.h". despite triple checking my CMakelists.txt and package.xml files I could not get catkin to "autogenerate" this file. Instead I found it in the hydro examples and used it as is. This then worked. Not a satisfactory solution! (there is an earlier question from 2011 with this same issue which was never answered!)

blakeh gravatar image blakeh  ( 2014-05-02 06:33:03 -0500 )edit

Ok I suppose you added it as a service in your CMakeList.txt? Furthermore you should also do message_generation in in add_dependencies. Then what you also need to do in hydro is add message_generation as a build_depend and as required component.

Jacco van der Spek gravatar image Jacco van der Spek  ( 2014-05-02 07:22:44 -0500 )edit

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Asked: 2014-04-30 13:18:34 -0500

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Last updated: Apr 30 '14