I'm trying to use ROS2 Humble on Ubuntu 20.04. I've built it from source as it was written in tutorial. Now I'm trying to build node, to do this I'm trying to install dependencies with rosdep, however I receive this error:
No definition of [cv_bridge] for OS version [focal]
I can't use Ubuntu 22.04, so is there any way to fix this problem? To install dependencies I use this line:
rosdep install -q -y -i --from-path . --rosdistro humble -r
ROS Humble Hawksbill is not available on Ubuntu Focal from debian packages, you need to use a tier 1 supported platform such as Ubuntu Jammy.
Supported platforms are listed on the Humble Distribution Description
You can continue to use Focal building Humble packages from source, but you will likely have a much better experience using Ubuntu Jammy on your system.
Specifically for your case cv_bridge is a ROS package and not a rosdep key. On a platform with binary installation available rosdep can install the binary packages for you. However on your system you have to resolve all the ROS package dependencies by checking out the source into your workspace.
The tool rosinstall_generator command with --deps option is commonly used to help you checkout all the necessary packages.
