BT-Canopy

Canopy is a tool for running code coverage on behavior trees in ROS2.

For a BT library to work with Canopy, that library must be able to publish its behavior tree state information in the format provided in the tree_msgs package. Out of the box, Canopy supports BehaviorTree.cpp (specifically v3) and py_trees_ros as detailed below.

Nav2 Case Study

The instructions/case study results for instrumenting Nav2 using Canopy can be found in examples/nav2_with_canopy and the corresponding README.md.

Instrumenting Logging

Canopy requires no extra instrumentation if the behavior tree being monitored is implemented using py_trees_ros. However, if the behavior tree being monitored is implemented using BehaviorTree.CPP, some modifications to the code being monitored. This includes adding a logger that publishes to a ROS topic. A basic implementation of this can be found in behaviortree_cpp_v3_ros2_publisher.

The project must add behaviortree_cpp_v3_ros2_publisher as a dependency for the ROS project.

CMakeLists.txt:

find_package(behaviortree_cpp_v3_ros2_publisher REQUIRED)

package.xml:

<build_depend>behaviortree_cpp_v3_ros2_publisher</build_depend>
<exec_depend>behaviortree_cpp_v3_ros2_publisher</exec_depend>

The following code should also be added to the project.

std::unique_ptr<BTRosPublisher> logger = std::make_unique<BTRosPublisher>(ros_node, tree, tree_uid);

logger->flush();

Where ros_node is the ROS node object that's running the behavior tree, tree is an instance of the BehaviorTree.CPP behavior tree, and tree_uid is some unique name for the behavior tree. The flush method must be called routinely in order for the logging information to get published to Canopy.

Enabling BehaviorTree.CPP Logging

• The user needs to import the included BTRosPublisher logger and initialize it after the behaviortree_cpp_v3 tree is initialized. For an example, see the working example

Building Canopy

The ROS dependencies should first be installed in the ROS workspace.

rosdep install --from-paths src --ignore-src -r -y

Running the build can be done simply with

colcon build --symlink-install

Running Canopy

Canopy can now be run simply by using the launch script.

. install/setup.sh
ros2 launch bt_canopy_bringup monitor.launch.py

In order to monitor py_trees_ros, the another node must be run in a separate terminal.

. install/setup.sh
ros2 launch py_trees_ros_publisher publisher.launch.py