robokudo.action_servers.action_server_base

Base module for implementing ROS action servers in RoboKudo.

This module provides a base class for creating ROS action servers that can:

  • Handle action goals and feedback

  • Process client requests asynchronously

  • Support preemption of running goals

  • Manage server lifecycle (initialization, starting, etc.)

The base class abstracts common action server functionality while allowing specific implementations through subclassing.

Classes

ActionServerBase

A base class for implementing ROS action servers.

Module Contents

class robokudo.action_servers.action_server_base.ActionServerBase(action, feedback, result, auto_start: bool = True)

A base class for implementing ROS action servers.

This class provides the core functionality needed to create ROS action servers in RoboKudo. It handles:

  • Server initialization and startup

  • Goal reception and processing

  • Feedback and result message management

  • Preemption support

Subclasses must implement the _compute_result method to define specific server behavior.

Variables:

  • logger – Logger instance for this action server

  • _feedback – Feedback message type for the action

  • _result – Result message type for the action

  • _action_server – The ROS action server instance

  • _feedback_msg – Current feedback message instance

  • _result_msg – Current result message instance

ros_pkg_name = 'robokudo'
name = 'action_server'
logger = None
_feedback
_result
_action_server
_feedback_msg = None
_result_msg = None
start_server()

Start the ROS action server.

Initializes feedback and result message instances and starts the underlying ROS action server.

_on_receive(goal)

Callback method executed when a new goal is received.

Processes the goal by calling _compute_result and handles success/failure cases appropriately.

Parameters:

goal (Any) – The goal received from a client

abstract _compute_result(goal) → bool

Compute result for a received goal.

This abstract method must be implemented by subclasses to define how goals are processed. During computation, implementations should:

  • Regularly call self._check_for_preempt() to handle preemption

  • Update self._feedback_msg with progress information

  • Call self._send_feedback() to publish feedback

  • Set self._result_msg with the final result

Parameters:

goal (Any) – The goal to process

Returns:

True if goal was processed successfully, False otherwise

Return type:

bool

_check_for_preempt() → bool

Check if the current goal has been preempted.

If preemption is requested, marks the goal as preempted and stops processing.

Returns:

True if preemption was requested, False otherwise

Return type:

bool

_send_feedback()

Send the current feedback message to the action client.

Publishes the current state of self._feedback_msg to update clients on goal processing progress.