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pythonrosrospy

Using ROS message classes outside of ROS

I have a ROS node written in Python that captures messages and writes them to disk (e.g. using pickle). I want to use these files later, in another Python script, outside of ROS, but I need to import the message classes.

Is that possible?

Thanks!

Solution

  • Unfortunately I don't think it's possible to just import the message files outside of any ROS dependencies. For example, if you look inside one of the generated message class files:

    ---/your_catkin_ws/devel/lib/python2.7/dist-packages/your_package/msg/_Message.py

    You will see that it depends at least on genpy and other message types contained in your message. Base messages are the same (in /opt/ros/indigo/lib/python2.7/dist-packages/std_msgs/msg).

    While you could try to copy the minimum amount of dependencies until It Finally Works(!), it's a little un-elegant and probably going to be a brittle solution.

    I believe the best solution is to convert your message to a generic non-ROS type, then store it in your pickle (so essentially what you've been doing already).