Actions¶
Action Client¶
- class rclpy.action.client.ActionClient(node, action_type, action_name, *, callback_group=None, goal_service_qos_profile=<rclpy.qos.QoSProfile object>, result_service_qos_profile=<rclpy.qos.QoSProfile object>, cancel_service_qos_profile=<rclpy.qos.QoSProfile object>, feedback_sub_qos_profile=<rclpy.qos.QoSProfile object>, status_sub_qos_profile=<rclpy.qos.QoSProfile object>)¶
ROS Action client.
Create an ActionClient.
- Parameters
node – The ROS node to add the action client to.
action_type – Type of the action.
action_name – Name of the action. Used as part of the underlying topic and service names.
callback_group – Callback group to add the action client to. If None, then the node’s default callback group is used.
goal_service_qos_profile – QoS profile for the goal service.
result_service_qos_profile – QoS profile for the result service.
cancel_service_qos_profile – QoS profile for the cancel service.
feedback_sub_qos_profile – QoS profile for the feedback subscriber.
status_sub_qos_profile – QoS profile for the status subscriber.
- add_to_wait_set(wait_set)¶
Add entities to wait set.
- destroy()¶
Destroy the underlying action client handle.
- async execute(taken_data)¶
Execute work after data has been taken from a ready wait set.
This will set results for Future objects for any received service responses and call any user-defined callbacks (e.g. feedback).
- get_num_entities()¶
Return number of each type of entity used in the wait set.
- is_ready(wait_set)¶
Return True if one or more entities are ready in the wait set.
- send_goal(goal, **kwargs)¶
Send a goal and wait for the result.
Do not call this method in a callback or a deadlock may occur.
See
send_goal_async()
for more info about keyword arguments.Unlike
send_goal_async()
, this method returns the final result of the action (not a goal handle).- Parameters
goal (action_type.Goal) – The goal request.
- Returns
The result response.
- Return type
action_type.Result
- Raises
TypeError if the type of the passed goal isn’t an instance of the Goal type of the provided action when the service was constructed.
- send_goal_async(goal, feedback_callback=None, goal_uuid=None)¶
Send a goal and asynchronously get the result.
The result of the returned Future is set to a ClientGoalHandle when receipt of the goal is acknowledged by an action server.
- Parameters
goal (action_type.Goal) – The goal request.
feedback_callback (function) – Callback function for feedback associated with the goal.
goal_uuid – Universally unique identifier for the goal. If None, then a random UUID is generated.
- Type
unique_identifier_msgs.UUID
- Returns
a Future instance to a goal handle that completes when the goal request has been accepted or rejected.
- Return type
rclpy.task.Future
instance- Raises
TypeError if the type of the passed goal isn’t an instance of the Goal type of the provided action when the service was constructed.
- server_is_ready()¶
Check if there is an action server ready to process requests from this client.
- Returns
True if an action server is ready, False otherwise.
- take_data()¶
Take stuff from lower level so the wait set doesn’t immediately wake again.
- wait_for_server(timeout_sec=None)¶
Wait for an action sever to be ready.
Returns as soon as an action server is ready for this client.
- Parameters
timeout_sec – Number of seconds to wait until an action server is available. If None, then wait indefinitely.
- Returns
True if an action server is available, False if the timeout is exceeded.
- class rclpy.action.client.ClientGoalHandle(action_client, goal_id, goal_response)¶
Goal handle for working with Action Clients.
- property accepted¶
- cancel_goal()¶
Send a cancel request for the goal and wait for the response.
Do not call this method in a callback or a deadlock may occur.
- Returns
The cancel response.
- cancel_goal_async()¶
Asynchronous request for the goal be canceled.
- Returns
a Future instance that completes when the server responds.
- Return type
rclpy.task.Future
instance
- get_result()¶
Request the result for the goal and wait for the response.
Do not call this method in a callback or a deadlock may occur.
- Returns
The result response.
- get_result_async()¶
Asynchronously request the goal result.
- Returns
a Future instance that completes when the result is ready.
- Return type
rclpy.task.Future
instance
- property goal_id¶
- property stamp¶
- property status¶
Action Server¶
- class rclpy.action.server.ActionServer(node, action_type, action_name, execute_callback, *, callback_group=None, goal_callback=<function default_goal_callback>, handle_accepted_callback=<function default_handle_accepted_callback>, cancel_callback=<function default_cancel_callback>, goal_service_qos_profile=<rclpy.qos.QoSProfile object>, result_service_qos_profile=<rclpy.qos.QoSProfile object>, cancel_service_qos_profile=<rclpy.qos.QoSProfile object>, feedback_pub_qos_profile=<rclpy.qos.QoSProfile object>, status_pub_qos_profile=<rclpy.qos.QoSProfile object>, result_timeout=900)¶
ROS Action server.
Create an ActionServer.
- Parameters
node – The ROS node to add the action server to.
action_type – Type of the action.
action_name – Name of the action. Used as part of the underlying topic and service names.
execute_callback – Callback function for processing accepted goals. This is called if when
ServerGoalHandle.execute()
is called for a goal handle that is being tracked by this action server.callback_group – Callback group to add the action server to. If None, then the node’s default callback group is used.
goal_callback – Callback function for handling new goal requests.
handle_accepted_callback – Callback function for handling newly accepted goals. Passes an instance of ServerGoalHandle as an argument.
cancel_callback – Callback function for handling cancel requests.
goal_service_qos_profile – QoS profile for the goal service.
result_service_qos_profile – QoS profile for the result service.
cancel_service_qos_profile – QoS profile for the cancel service.
feedback_pub_qos_profile – QoS profile for the feedback publisher.
status_pub_qos_profile – QoS profile for the status publisher.
result_timeout – How long in seconds a result is kept by the server after a goal reaches a terminal state.
- property action_type¶
- add_to_wait_set(wait_set)¶
Add entities to wait set.
- destroy()¶
Destroy the underlying action server handle.
- async execute(taken_data)¶
Execute work after data has been taken from a ready wait set.
This will set results for Future objects for any received service responses and call any user-defined callbacks (e.g. feedback).
- get_num_entities()¶
Return number of each type of entity used in the wait set.
- is_ready(wait_set)¶
Return True if one or more entities are ready in the wait set.
- notify_execute(goal_handle, execute_callback)¶
- notify_goal_done()¶
- register_cancel_callback(cancel_callback)¶
Register a callback for handling cancel requests.
The purpose of the cancel callback is to decide if a request to cancel an on-going (or queued) goal should be accepted or rejected. The callback should take one parameter containing the cancel request and must return a
CancelResponse
value.There can only be one cancel callback per
ActionServer
, therefore calling this function will replace any previously registered callback.- Parameters
cancel_callback – Callback function, if None, then unregisters any previously registered callback.
- register_execute_callback(execute_callback)¶
Register a callback for executing action goals.
The purpose of the execute callback is to execute the action goal and return a result when finished.
The callback should take one parameter containing goal request and must return a result instance (i.e. action_type.Result).
There can only be one execute callback per
ActionServer
, therefore calling this function will replace any previously registered callback.- Parameters
execute_callback – Callback function. Must not be None.
- register_goal_callback(goal_callback)¶
Register a callback for handling new goal requests.
The purpose of the goal callback is to decide if a new goal should be accepted or rejected. The callback should take the goal request message as a parameter and must return a
GoalResponse
value.There can only be one goal callback per
ActionServer
, therefore calling this function will replace any previously registered callback.- Parameters
goal_callback – Callback function, if None, then unregisters any previously registered callback.
- register_handle_accepted_callback(handle_accepted_callback)¶
Register a callback for handling newly accepted goals.
The provided function is called whenever a new goal has been accepted by this action server. The function should expect an instance of
ServerGoalHandle
as an argument, which represents a handle to the goal that was accepted. The goal handle can be used to interact with the goal, e.g. publish feedback, update the status, or execute a deferred goal.There can only be one handle accepted callback per
ActionServer
, therefore calling this function will replace any previously registered callback.- Parameters
goal_callback – Callback function, if None, then unregisters any previously registered callback.
- take_data()¶
Take stuff from lower level so the wait set doesn’t immediately wake again.
- class rclpy.action.server.GoalEvent(value)¶
Goal events that cause state transitions.
- ABORT = 4¶
- CANCELED = 5¶
- CANCEL_GOAL = 2¶
- EXECUTE = 1¶
- SUCCEED = 3¶
- class rclpy.action.server.ServerGoalHandle(action_server, goal_info, goal_request)¶
Goal handle for working with Action Servers.
Accept a new goal with the given action server.
Instances of this class should only be constructed in the ActionServer class. Instances for accepted goals will be passed to the user-defined goal execution functions.
If the goal fails to be accepted, then a RuntimeError is raised.
- Parameters
action_server – The ActionServer to accept the goal.
goal_info – GoalInfo message.
goal_request – The user defined goal request message from an ActionClient.
- abort()¶
- canceled()¶
- destroy()¶
- execute(execute_callback=None)¶
- property goal_id¶
- property is_active¶
- property is_cancel_requested¶
- publish_feedback(feedback)¶
- property request¶
- property status¶
- succeed()¶
- rclpy.action.server.default_cancel_callback(cancel_request)¶
No cancellations.
- rclpy.action.server.default_goal_callback(goal_request)¶
Accept all goals.
- rclpy.action.server.default_handle_accepted_callback(goal_handle)¶
Execute the goal.