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If I need to import let's say numpy in a ROS2 Python node, how does that work? I added it to package.xml but I'm getting getting "ModuleNotFoundError: No module named 'dynamixel_sdk'". Do I need to add it somewhere use? Should I use a venv?
It's important to add all of your dependencies to the package.xml. That does a few different things:
rosdep know which packages to install from the system.apt-get install ros-foxy-<mypackage> installs all of the dependencies.That being said, adding to the package.xml doesn't modify your environment at all. So it won't help your python package to "find" dependencies. Essentially if you can run python3 and import <dep>, then your package should be able to find it. Typically those are either from system packages, or through pip.
Sorry I'm still slightly confused. Just to make sure I understand... so in my case, I should add dynamixel_sdk to the package.xml... and since it is in package.xml... rosdep should be able to install it? I used pip to install the sdk, but I guess if someone else used rosdep, that would work?
The general idea with listing your dependencies in the package.xml is so that your users can just use rosdep to install the dependencies. At least for system packages (ones you can install with apt install), that's how it works. I'm not quite sure how pip packages work there, but I think it works in a similar way.
Asked: 2020-12-08 17:02:14 -0500
Seen: 2,061 times
Last updated: Dec 18 '20
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Btw, this question was asked here as well but didn't receive an answer: https://answers.ros.org/question/3656...
Just following up... It doesn't seem like it did anything to add it to package.xml, although I saw this in some Github repos. I think I will just use a venv / requirements.txt, although I'm not sure that this is the best approach.
We spent a little time documenting this a bit more, maybe this will help: https://index.ros.org/doc/ros2/Tutori...
Thanks so much for the documentation!! I'm guessing you meant to link to https://index.ros.org/doc/ros2/Tutori...