rosdep install specific version of dependencies

edit

So what is the proper way to install specific version of python packages within ROS project? Should I create a virtual environment, locate requirements.txt in package root and install it straight via pip? Seems unprofessional.

Correct you should not generally override the version on the system. You can do it if you're only ever expecting users to work from source and that they will all know about the full system configuration and won't get suprised if another package with that same dependency starts failing due to the alternative version. (In reality that sort of user is only a power user/deployment expert. And even then they're not going to want to be working from source.)

It's generally not recommended to rely on a very specific version, but to make sure that your code is compatible with the standard versions available via package managers on the distro's target platforms.

To do it properly you should embed a virtualenv inside of your package and keep it isolated such that it won't interfere with any other packages in the workspace or on the system.

So what is the proper way to install specific version of python packages within ROS project? Should I create a virtual environment, locate requirements.txt in package root and install it straight via pip?

It's not necessarily official or proper, but catkin_virtualenv was created to do what you describe, while still being 100% compatible with the regular Catkin workflow and ROS workspaces.

It basically does what @tfoote suggests ("embedding a venv inside your package"), but in a more automated way.

@gvdhoorn is that ROS 1 specific? is the same available for ROS 2?

Also, there's currently a PR open to make rosdep support versions in pip:

https://github.com/ros-infrastructure...

catkin_virtualenv is only for ROS 1, as the catkin in the name implies.

There is a "ROS 2 port" (basically a rewrite) at esol-community/ament_virtualenv. I'm not sure what the status of it is. It's been 4 years since I last looked at it.