nodl_to_policy

This repository contains tooling to generate a ROS 2 Access Control Policy from the Node Interface Definition Language (NoDL) description of a ROS system (or that of a specific package), primarily to be used in conjunction with the SROS2 utilities.

Building

• Clone this repository to a ROS workspace: git clone git@github.com:osrf/nodl_to_policy.git <ws/src>/nodl_to_policy
• Install required dependencies: rosdep install -yri --from-paths <ws/src> --rosdistro=galactic
• Build with: colcon build --symlink-install

Usage

CLI

The nodl_to_policy package extends the ROS 2 CLI by adding a nodl_to_policy command, with an associated convert verb. The expected use is as follows:

ros2 nodl_to_policy convert <path-to-NoDL-file (*.nodl.xml)>

Invoking the convert verb as above dumps the resulting access control policy in the console standard output. If desired, this output can be redirected (>) to <output>.policy.xml.

API

The NoDL → policy conversion method simply takes a NoDL description (type: List[nodl.Node]). As such, the conversion API could be used programmatically as follows:

from nodl_to_python.policy import convert_to_policy

# obtain a NoDL description, either through `nodl.parse(<nodl_file_path>)` or otherwise

policy = convert_to_policy(nodl_description)  # type(nodl_description) == List[nodl.Node]

# use policy, and/or output it using `nodl.dump_policy(policy, <output_stream>)`