Support for ROS2 Dashing along with python3

[shikharvaish28]

  File "ros_pp.py", line 12, in <module>
    from tf2_ros.src.tf2_ros.transform_listener import TransformListener
  File "../../../src/geometry2/tf2_ros/src/tf2_ros/__init__.py", line 39, in <module>
    from buffer_interface import *
ModuleNotFoundError: No module named 'buffer_interface'

I have built the geometry library for my project using colcon for ROS2 Dashing and Python 3 and sourced it using source install/setup.bash but am getting this error on importing the TransformListener from tf2_ros.

My directory structure is as follows:

-workspace
         - build
         - install
         - src
                -  my_module
                          - src
                              - file.py
                -  geometry2

It would be great if anyone could help me know where exactly the error is coming from.

[clalancette]

The basic problem is that we haven't ported the python portion of tf2/tf2_ros to ROS 2 yet. In point of fact, you got further than I think you should have; it should have failed to find the tf2_ros module, not just the buffer_interface. Are you using some custom geometry2 code?

[shikharvaish28]

Thanks for the clarification @clalancette

Are you using some custom geometry2 code?

Yes, I altered a couple of lines thinking that it would work but now it appears that it requires more work.

The basic problem is that we haven't ported the python portion of tf2/tf2_ros to ROS 2 yet.

Okay, now I get it. So I guess, I will have to use the tf2 in CPP as of now. Is tf2_ros fully supporting ROS2 dashing?

[clalancette]

Okay, now I get it. So I guess, I will have to use the tf2 in CPP as of now. Is tf2_ros fully supporting ROS2 dashing?

Yes, we've ported the C++ version of tf2_ros to Dashing. All of the major components are there, but do please let us know if you run into issues (or even better, open a PR to fix them).

I'm going to close this out since it is essentially a duplicate of #99, but feel free to reopen if you need something different.