Can't display /moving and /stop services in Unit 4

Hello. After running
source /opt/ros/galactic/setup.sh
ros2 service list
I can’t see the /moving and /stop services in the terminal.

And when I run ros2 service type /moving nothing is displayed

image

Any solution?

Thank you

Hey @ShikurM56 !

Have you started the service nodes? You need to start the services to see the topics.

If you have started the services, then it means they are not working properly and need to be checked.

Hello @bayodesegun . Thanks for your reply.

Which command do I need to start the services?
I am in the 4.2 Basic Service Commands

Those services are running but not the expected two ( /moving, /stop )

user:~$ ros2 service list
/camera_driver/describe_parameters
/camera_driver/get_parameter_types
/camera_driver/get_parameters
/camera_driver/list_parameters
/camera_driver/set_parameters
/camera_driver/set_parameters_atomically
/gazebo/describe_parameters
/gazebo/get_parameter_types
/gazebo/get_parameters
/gazebo/list_parameters
/gazebo/set_parameters
/gazebo/set_parameters_atomically
/pause_physics
/reset_simulation
/reset_world
/robot_state_publisher/describe_parameters
/robot_state_publisher/get_parameter_types
/robot_state_publisher/get_parameters
/robot_state_publisher/list_parameters
/robot_state_publisher/set_parameters
/robot_state_publisher/set_parameters_atomically
/set_camera_info
/turtlebot3_diff_drive/describe_parameters
/turtlebot3_diff_drive/get_parameter_types
/turtlebot3_diff_drive/get_parameters
/turtlebot3_diff_drive/list_parameters
/turtlebot3_diff_drive/set_parameters
/turtlebot3_diff_drive/set_parameters_atomically
/turtlebot3_imu/describe_parameters
/turtlebot3_imu/get_parameter_types
/turtlebot3_imu/get_parameters
/turtlebot3_imu/list_parameters
/turtlebot3_imu/set_parameters
/turtlebot3_imu/set_parameters_atomically
/turtlebot3_joint_state/describe_parameters
/turtlebot3_joint_state/get_parameter_types
/turtlebot3_joint_state/get_parameters
/turtlebot3_joint_state/list_parameters
/turtlebot3_joint_state/set_parameters
/turtlebot3_joint_state/set_parameters_atomically
/turtlebot3_laserscan/describe_parameters
/turtlebot3_laserscan/get_parameter_types
/turtlebot3_laserscan/get_parameters
/turtlebot3_laserscan/list_parameters
/turtlebot3_laserscan/set_parameters
/turtlebot3_laserscan/set_parameters_atomically
/unpause_physics

Thank you

My apologies, there seems to be a bug in the course, those services are meant to be provided automatically but somehow, they are not. Or the instruction to start them is missing.

Let’s fix that and get back to you.

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Hello @ShikurM56 ,

I’ve just fixed this error in the Unit. Now you should be able to see the services normally. Sorry for the inconvenience.

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Hello @albertoezquerro @bayodesegun

The bug is already fixed, thank you

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