What Is This?

This package contains the following ROS 2 nodes:

1. listener
2. talker
3. add_two_ints_client
4. add_two_ints_server
5. set_parameters_callback
6. add_two_ints_client_async
7. listener_qos
8. talker_qos
9. listerner_serialized
10. async_param_client

Build

Run this command to build the package:

colcon build --packages-select demo_nodes_py

Run

Basic Listener & Talker

This runs talker and listener ROS 2 nodes which exchange the following string with incremeting integer:

Hello World:

# Open new terminal
ros2 run demo_nodes_py talker

# Open new terminal
ros2 run demo_nodes_py listener

Server & Client

This runs add_two_ints_client and add_two_ints_server ROS 2 client and server where the server processes two integers sent from the client and publishes its sum to the client to be printed out.

Server

# Open new terminal
ros2 run demo_nodes_py add_two_ints_server

Client [Synchronous]

# Open new terminal
ros2 run demo_nodes_py add_two_ints_client

Client [Asynchronous]

# Open new terminal
ros2 run demo_nodes_py add_two_ints_client_async

QoS Listener & Talker

Similar to previous, this runs talker_qos and listener_qos ROS 2 nodes which exchange messages using the Quality of Service (QoS) best effort policy.

# Open new terminal
ros2 run demo_nodes_py talker_qos

# Open new terminal
ros2 run demo_nodes_py listener_qos

Set Parameters Callback

This runs set_parameters_callback ROS 2 node which triggers a callback when ROS 2 double parameter param1 is set. The callback then sets ROS 2 double parameter param2 to a fixed 4.0:

# Open new terminal
ros2 run demo_nodes_py set_parameters_callback

Asynchronous Parameter Client

This runs async_param_client ROS 2 node which demonstrates how to set, list, get, load and delete parameters from the parameter blackboard in an asynchronous manner:

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Changelog for package demo_nodes_py

0.27.2 (2024-07-10)

0.27.1 (2023-05-11)

0.27.0 (2023-04-13)

• Change all ROS2 -> ROS 2. (#610)
• Add matched event demo for rclcpp and rclpy (#607)
• Contributors: Barry Xu, Chris Lalancette

0.26.0 (2023-04-11)

• Enable document generation using rosdoc2 (#606)
• Contributors: Yadu

0.25.0 (2023-03-01)

• Service introspection (#602)
• Contributors: Chris Lalancette

0.24.1 (2023-02-24)

0.24.0 (2023-02-14)

• Added README.md for demo_nodes_py (#600)
• [rolling] Update maintainers - 2022-11-07 (#589)
• Contributors: Audrow Nash, Gary Bey

0.23.0 (2022-11-02)

• Demo for pre and post set parameter callback support (#565)
• Contributors: Deepanshu Bansal

0.22.0 (2022-09-13)

• Add demo for rclpy parameter client (#566)
• Exit with code 0 if ExternalShutdownException is raised (#581)
• Contributors: Brian, Jacob Perron

0.21.0 (2022-04-29)

0.20.1 (2022-04-08)

0.20.0 (2022-03-01)

• Cleanups in demo_nodes_py. (#555)
• Contributors: Chris Lalancette

0.19.0 (2022-01-14)

0.18.0 (2021-12-17)

• Update maintainers to Audrow Nash and Michael Jeronimo (#543)
• Fixed typo executor -> executors (#542)
• Update python nodes SIGINT handling (#539)
• Contributors: Audrow Nash, Ivan Santiago Paunovic, ori155

0.17.0 (2021-10-18)

0.16.0 (2021-08-11)

0.15.0 (2021-05-14)

0.14.2 (2021-04-26)

0.14.1 (2021-04-19)

• Use underscores instead of dashes in setup.cfg (#502)
• Contributors: Ivan Santiago Paunovic

0.14.0 (2021-04-06)

0.13.0 (2021-03-25)

0.12.1 (2021-03-18)

0.12.0 (2021-01-25)

0.11.0 (2020-12-10)

• Update deprecated qos policy value names (#468)
• Update the package.xml files with the latest Open Robotics maintainers (#466)

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