File Extraction

In certain situations, it is very useful to be able to locate and extract files from running Docker containers on a ROS2-enabled machine. These can be for instance URDF mesh files (STL, OBJ, DAE), as used and displayed by the Scene View widget.

Files are uploaded to the Bridge Server, cached and served from there on subsequent requests to save on robot’s networking bandwidth. In order to invalidate this cache, call the phntm_bridge/clear_cloud_file_cache service (availale in the Services menu in the Web UI).

_images/file-extraction.svg

Notes

  • Only package:// or file:// URLS are supported in the URDF

  • When locating a file via package://, it is important for the Docker container containing the package to have $ROS_WS environmental variable set as we need to source the ROS environment from $ROS_WS/install/setup.bash during the file search. The search operation attempts to source ~/.bashrc too, so you can alternatively source your ROS2 environment there (which we recommend as a good practice).

  • Thanks to the standalone Bridge Agent design, it is possible to extract files from all parts of a distributed system. One Agent instance needs to be installed on every component.