Generic behavior tree node wrapper for a ROS 2 subscriber. More...

#include <auto_apms_behavior_tree_core/node/ros_subscriber_node.hpp>

Public Member Functions
	RosSubscriberNode (const std::string &instance_name, const Config &config, Context context, const rclcpp::QoS &qos={10})
	Constructor.

virtual BT::NodeStatus	onTick (const std::shared_ptr< MessageT > &last_msg_ptr)
	Callback invoked when the node is ticked.

virtual BT::NodeStatus	onMessageReceived (const MessageT &msg)
	Callback invoked when the node is ticked and a valid message has been received.

bool	createSubscriber (const std::string &topic_name)
	Create the ROS 2 subscriber.

std::string	getTopicName () const
	Get the name of the topic name this node subscribes to.

Static Public Member Functions
static BT::PortsList	providedBasicPorts (BT::PortsList addition)
	Derived nodes implementing the static method RosSubscriberNode::providedPorts may call this method to also include the default port for ROS 2 behavior tree nodes.

static BT::PortsList	providedPorts ()
	If a behavior tree requires input/output data ports, the developer must define this method accordingly.

Detailed Description

template<class MessageT>
class auto_apms_behavior_tree::core::RosSubscriberNode< MessageT >

Generic behavior tree node wrapper for a ROS 2 subscriber.

When ticked, this node may inspect the last message that has been received on a specific topic. Inheriting classes must reimplement the virtual methods as described below.

By default, the name of the topic will be determined as follows:

If a value is passed using the input port named port, use that.
Otherwise, use the value from NodeRegistrationOptions::port passed on construction as part of RosNodeContext.

It is possible to customize which port is used to determine the topic name and also extend the input's value with a prefix or suffix. This is achieved by including the special pattern (input:<port_name>) in NodeRegistrationOptions::port and replacing <port_name> with the desired input port name.

Example: Given the user implements an input port BT::InputPort<std::string>("my_port"), one may create a client for the topic "foo/bar" by defining NodeRegistrationOptions::port as (input:my_port)/bar and providing the string "foo" to the port with name my_port.

Additionally, the following characteristics depend on NodeRegistrationOptions:

logger_level: Minimum severity level enabled for logging using the ROS 2 Logger API.

Template Parameters

MessageT Type of the ROS 2 message.

Definition at line 59 of file ros_subscriber_node.hpp.

Constructor & Destructor Documentation

◆ RosSubscriberNode()

template<class MessageT>

RosSubscriberNode	(	const std::string &	instance_name,
		const Config &	config,
		Context	context,
		const rclcpp::QoS &	qos = {10} )

inlineexplicit

Constructor.

Derived nodes are automatically created by TreeBuilder::instantiate when included inside a node manifest associated with the behavior tree resource.

Parameters

instance_name	Name given to this specific node instance.
config	Structure of internal data determined at runtime by BT::BehaviorTreeFactory.
context	Additional parameters specific to ROS 2 determined at runtime by TreeBuilder.
qos	Quality of service settings forwarded to the subscriber.

Definition at line 196 of file ros_subscriber_node.hpp.

Member Function Documentation

◆ providedBasicPorts()

template<class MessageT>

static BT::PortsList providedBasicPorts ( BT::PortsList addition )

inlinestatic

Derived nodes implementing the static method RosSubscriberNode::providedPorts may call this method to also include the default port for ROS 2 behavior tree nodes.

Parameters

addition Additional ports to add to the ports list.

Returns: List of ports containing the default port along with node-specific ports.

Definition at line 104 of file ros_subscriber_node.hpp.

◆ providedPorts()

template<class MessageT>

static BT::PortsList providedPorts ( )

inlinestatic

If a behavior tree requires input/output data ports, the developer must define this method accordingly.

Returns: List of ports used by this node.

Definition at line 115 of file ros_subscriber_node.hpp.

◆ onTick()

template<class MessageT>

BT::NodeStatus onTick ( const std::shared_ptr< MessageT > & last_msg_ptr )

inlinevirtual

Callback invoked when the node is ticked.

By default, this method forwards the most recent message to RosSubscriberNode::onMessageReceived and leaves it up to this method to determine the node's return status. If no message has been received yet, it immediately returns BT::NodeStatus::FAILURE. If you want to change that behavior, you should override this method.

Parameters

last_msg_ptr The latest message received, since the last tick. Will be nullptr if no new message was received.

Returns: Return status of the node based on last_msg_ptr.

Definition at line 314 of file ros_subscriber_node.hpp.

◆ onMessageReceived()

template<class MessageT>

BT::NodeStatus onMessageReceived ( const MessageT & msg )

inlinevirtual

Callback invoked when the node is ticked and a valid message has been received.

This callback won't be invoked if no message is available at the time this node is ticked. If you need to evaluate an expression every time this node is ticked, refer to RosSubscriberNode::onTick instead and change its default implementation.

Parameters

msg	Most recently received message.

Returns: Return status of the node based on msg.

Definition at line 321 of file ros_subscriber_node.hpp.

◆ createSubscriber()

template<class MessageT>

bool createSubscriber ( const std::string & topic_name )

inline

Create the ROS 2 subscriber.

Parameters

topic_name Name of the topic.

Returns: true if the subscriber was created successfully, false otherwise.

Definition at line 214 of file ros_subscriber_node.hpp.

◆ getTopicName()

template<class MessageT>

std::string getTopicName ( ) const

inline

Get the name of the topic name this node subscribes to.

Returns: String representing the topic name.

Definition at line 327 of file ros_subscriber_node.hpp.

The documentation for this class was generated from the following file:

auto_apms_behavior_tree_core/include/auto_apms_behavior_tree_core/node/ros_subscriber_node.hpp

Public Member Functions

Static Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ RosSubscriberNode()

Member Function Documentation

◆ providedBasicPorts()

◆ providedPorts()

◆ onTick()

◆ onMessageReceived()

◆ createSubscriber()

◆ getTopicName()