RosNode

Inherits: RefCounted

A ROS 2 Node that manages publishers, subscribers, and other communication interfaces.

Description

The RosNode is the primary interface for interacting with the ROS 2 network. It provides factory methods to create publishers, subscribers, clients, and services, and allows management of node-level parameters and timers.

A node must be initialized using init() before it can be used to create other communication components.

Methods

int	count_publishers(topic: String)
int	count_subscribers(topic: String)
RosActionClient	create_action_client(action_name: String, action_type: Variant, qos: RosQoS = null)
RosActionServer	create_action_server(action_name: String, action_type: Variant, execute_callback: Callable, goal_callback: Callable = Callable(), qos: RosQoS = null)
RosClient	create_client(srv_name: String, srv_type: Variant, qos: RosQoS = null)
RosPublisher	create_publisher(topic: String, type: Variant, qos: RosQoS = null)
RosService	create_service(srv_name: String, srv_type: Variant, callback: Callable, qos: RosQoS = null)
RosSubscriber	create_subscription(topic: String, type: Variant, callback: Callable, qos: RosQoS = null)
RosTfBroadcaster	create_tf_broadcaster()
RosTfListener	create_tf_listener()
RosTimer	create_timer(seconds: float, callback: Callable)
void	declare_parameter(name: String, default_value: Variant)
String	get_name() const
String	get_namespace() const
Variant	get_parameter(name: String)
Dictionary	get_topic_names_and_types()
void	init(node_name: String, namespace: String = "")
RosMsg	now()
String	resolve_frame(frame_id: String)
void	set_parameter(name: String, value: Variant)

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Signals

parameter_changed(name: String, value: Variant) 🔗

Emitted whenever a node parameter is updated by an external tool or by set_parameter() locally.

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Method Descriptions

int count_publishers(topic: String) 🔗

Returns the number of publishers currently active on a specific topic in the ROS 2 graph.

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int count_subscribers(topic: String) 🔗

Returns the number of subscribers currently active on a specific topic in the ROS 2 graph.

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RosActionClient create_action_client(action_name: String, action_type: Variant, qos: RosQoS = null) 🔗

Creates and returns a RosActionClient for the specified action_name and action_type (e.g. "example_interfaces/action/Fibonacci"). Use qos to configure the Quality of Service for the action client.

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RosActionServer create_action_server(action_name: String, action_type: Variant, execute_callback: Callable, goal_callback: Callable = Callable(), qos: RosQoS = null) 🔗

Creates and returns a RosActionServer for the specified action_name and action_type. Incoming goals are auto-accepted and handed to execute_callback on the main thread as a RosServerGoalHandle, which must be driven to a terminal state. The goal_callback can optionally be used to reject goals. Use qos to configure the Quality of Service for the action server. See RosActionServer for a full example.

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RosClient create_client(srv_name: String, srv_type: Variant, qos: RosQoS = null) 🔗

Creates and returns a RosClient for the specified service name and type. Use qos to configure the Quality of Service for the client.

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RosPublisher create_publisher(topic: String, type: Variant, qos: RosQoS = null) 🔗

Creates and returns a RosPublisher to send messages to a specific topic. Use qos to configure the Quality of Service for the publisher.

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RosService create_service(srv_name: String, srv_type: Variant, callback: Callable, qos: RosQoS = null) 🔗

Creates and returns a RosService server for the specified service name and type. The callback is triggered whenever a request is received. Use qos to configure the Quality of Service for the service server.

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RosSubscriber create_subscription(topic: String, type: Variant, callback: Callable, qos: RosQoS = null) 🔗

Creates and returns a RosSubscriber to receive messages from a specific topic. The callback is triggered for every new message received, always on the Godot main thread. Use qos to configure the Quality of Service for the subscription.

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RosTfBroadcaster create_tf_broadcaster() 🔗

Creates and returns a RosTfBroadcaster for publishing coordinate transforms into the TF2 system.

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RosTfListener create_tf_listener() 🔗

Creates and returns a RosTfListener for looking up coordinate transforms in the TF2 system.

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RosTimer create_timer(seconds: float, callback: Callable) 🔗

Creates and returns a RosTimer that triggers the callback at the specified seconds interval, synced with the ROS 2 executor's clock.

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void declare_parameter(name: String, default_value: Variant) 🔗

Declares a parameter on the node with a default_value. Parameters must be declared before they can be retrieved or modified by external tools.

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String get_name() const 🔗

Returns the name of the node as registered in the ROS 2 graph.

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String get_namespace() const 🔗

Returns the namespace of the node.

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Variant get_parameter(name: String) 🔗

Returns the current value of the parameter with the specified name.

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Dictionary get_topic_names_and_types() 🔗

Returns a Dictionary containing all currently active topic names as keys and their associated message types as values.

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void init(node_name: String, namespace: String = "") 🔗

Initializes the node with a node_name and an optional namespace. This must be called before using any other functions of the node.

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RosMsg now() 🔗

Returns the current ROS 2 system time as a RosMsg of type builtin_interfaces/msg/Time.

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String resolve_frame(frame_id: String) 🔗

Prepends the node's namespace to a frame_id if it is not already absolute, helping resolve local frame names in multi-agent simulations.

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void set_parameter(name: String, value: Variant) 🔗

Sets the value of a previously declared parameter on the node.