Allow passing additional search paths from env var

Author: flferretti

src/resolve_robotics_uri_py/resolve_robotics_uri_py.py

@@ -95,14 +95,20 @@ def resolve_robotics_uri(
     Note:
         By default the function will look for the file in the
         default search paths specified by the environment variables in `SupportedEnvVars`.
- 
+
         If the `package_dirs` argument is provided, the model is also searched in the folders
         specified in `package_dirs` . In particular if a file is specified by the uri
-        `package://ModelName/meshes/mesh.stl`, and the actual file is in 
+        `package://ModelName/meshes/mesh.stl`, and the actual file is in
         `/usr/local/share/ModelName/meshes/mesh.stl`, the `package_dirs` should contain `/usr/local/share`.
     """
     package_dirs = package_dirs if isinstance(package_dirs, list) else [package_dirs]
 
+    # Add additional search paths from the RRU_ADDITIONAL_PATHS environment variable
+    if additional_paths := os.getenv("RRU_ADDITIONAL_PATHS"):
+        # Split the paths by os.pathsep and add them to the package_dirs
+        package_dirs += additional_paths.split(os.pathsep)
+        package_dirs = list({path for path in package_dirs if path and path != ""})
+
     # If the URI has no scheme, use by default file:// which maps the resolved input
     # path to a URI with empty authority
     if not any(uri.startswith(scheme) for scheme in SupportedSchemes):