action-server-client

To implement a ROS 2 action server and client in Python, use templates that handle goal processing, stream progress feedback, and support cancellation. This defines a robust end-to-end action workflow for coordinating long-running robotic tasks.

Preemption handling in ROS 2 action servers manages the goal lifecycle to safely cancel or replace active goals. Applying high-performance C++ server patterns prevents deadlocks and ensures safe task interruption during robotic control workflows.

The best way to coordinate long-running tasks in ROS 2 Jazzy and Rolling is using action servers and clients. They provide built-in goal tracking, continuous progress feedback, and safe cancellation to handle complex robotic control workflows.

You can test ROS 2 action server and client interactions using provided test scaffolding and concrete examples. Set up a Patrol.action definition, implement the server and client, and exercise a sample goal to verify end-to-end behavior.

Yes, you need to define a custom action file like Patrol.action before implementation. This action definition template establishes the goal, feedback, and result message structures required for the server and client to communicate properly.

ROS 2 action workflows hang during goal cancellation when preemption patterns are not implemented safely. Applying proper goal lifecycle management and preemption handling prevents deadlocks and ensures safe task interruption across server and client nodes.