Allow user to pass custom search paths

[flferretti]

When using robot_descriptions, this library cannot resolve the URIs due to the fact that robot_descriptions does not expose any environment variable of the one supported:

SupportedEnvVars = {
    "AMENT_PREFIX_PATH",
    "GAZEBO_MODEL_PATH",
    "GZ_SIM_RESOURCE_PATH",
    "IGN_GAZEBO_RESOURCE_PATH",
    "ROS_PACKAGE_PATH",
    "SDF_PATH",
}

As a result, resolve_robotics_uri_py cannot locate the necessary resources. Do you think that it could be beneficial to allow passing an additional environment variable for specifying custom search path as in 1c9e78f?

C.C. @traversaro @lorycontixd

[traversaro]

Good point, this is indeed something supported by many libraries, see RobotLocomotion/drake-external-examples#170 .

Do you think that it could be beneficial to allow passing an additional environment variable for specifying custom search path as in 1c9e78f?

In which sense "an additional environment variable" ? I guess you want an additional argument to the function, not an env variable?

However, I am a bit confused how existing users of robot_descriptions can resolve package:// URIs if no env variables are set.

[traversaro]

However, I am a bit confused how existing users of robot_descriptions can resolve package:// URIs if no env variables are set.

Mistery solved, the library-specific loaders handle that (see https://github.com/robot-descriptions/robot_descriptions.py/blob/d0dc260953a459450e73d9a4b456fd0b02ace59d/robot_descriptions/loaders/idyntree.py#L54C39-L54C55 for example with iDynTree). Then I guess it totally make sense to have this functionality here, can you open a PR so it is easier to discuss the change?

[traversaro]

I would also try to clearly document what extraPath is supposed to contain, see for example the Note in https://robotology.github.io/idyntree/classiDynTree_1_1ModelLoader.html#afefe79c0d50cfbaad54d5b076a90f00d .

[flferretti]

Good point, this is indeed something supported by many libraries, see RobotLocomotion/drake-external-examples#170 .

Do you think that it could be beneficial to allow passing an additional environment variable for specifying custom search path as in 1c9e78f?

In which sense "an additional environment variable" ? I guess you want an additional argument to the function, not an env variable?

However, I am a bit confused how existing users of robot_descriptions can resolve package:// URIs if no env variables are set.

Yes, sorry, I meant an extra argument that represents an environment variable associated with an additional search path

[flferretti]

Closed by #13