ROS2 Basics in 5 Days Gradebot Not subscribed to /odom

[sophiams]

Hi,
after passing the check in the past, and as far as I can remember not touching the subscription, the subscription check fails.

[13:48:46][assess] Not subscribed to /odom. Let's get this sorted first.
Please check:
- Did you create a subscriber correctly to the topic /odom in your source code?
- Did you use the right node name? It should be topics_quiz_node

Relevant Output of ros2 topic info -v /odom when running the node myself:

Type: nav_msgs/msg/Odometry

Publisher count: 1
...

Subscription count: 1

Node name: topics_quiz_node

I have gone over the relevant posts I found in the forum, I can’t find a location where the package is not called ‘package_quiz’ or where the node is not called ‘topics_quiz_node’. The output of the topic info seems to confirm this to me.

[bayodesegun]

How are you running the node? When the gradebot runs:

ros2 launch topics_quiz topics_quiz.launch.py

and then

ros2 topic info -v /odom

The output is something like:

Subscription count: 1

Node name: _NODE_NAME_UNKNOWN_
Node namespace: _NODE_NAMESPACE_UNKNOWN_
Topic type: nav_msgs/msg/Odometry
Endpoint type: SUBSCRIPTION
GID: 01.0f.2d.ef.42.03.a1.ae.01.00.00.00.00.00.12.04.00.00.00.00.00.00.00.00
QoS profile:
  Reliability: RELIABLE
  History (Depth): UNKNOWN
  Durability: VOLATILE
  Lifespan: Infinite
  Deadline: Infinite
  Liveliness: AUTOMATIC
  Liveliness lease duration: Infinite'

Check the node name specified in the launch file and setup.py

[sophiams]

Thank you for your response. This is from a freshly restarted terminal:

user:~$ cd ros2_ws/
user:~/ros2_ws$ source /opt/ros/humble/setup.bash
user:~/ros2_ws$ colcon build --packages-select topics_quiz
Starting >>> topics_quiz
Finished <<< topics_quiz [2.02s]

Summary: 1 package finished [2.69s]
user:~/ros2_ws$ source ~/ros2_ws/install/setup.bash
user:~/ros2_ws$ ros2 launch topics_quiz topics_quiz.launch.py
[INFO] [launch]: All log files can be found below /home/user/.ros/log/2024-02-21-13-59-57-038451-3_xterm-7428
[INFO] [launch]: Default logging verbosity is set to INFO
[INFO] [topics_quiz_node-1]: process started with pid [7429]
[topics_quiz_node-1] [INFO] [1708523998.015842550] [topics_quiz_node]: Step 1 COMPLETE
[topics_quiz_node-1] [INFO] [1708523998.016742578] [topics_quiz_node]: Step 2: Rotating neg: 170.94650375553155

The launch file:

from launch import LaunchDescription
from launch_ros.actions import Node

def generate_launch_description():
    return LaunchDescription([
        Node(
            package='topics_quiz',
            executable='topics_quiz_node',
            output='screen'),
    ])

The relevant sections of the setup.py:

from setuptools import setup
import os
from glob import glob

package_name = 'topics_quiz'

setup(
    name=package_name,
    version='0.0.0',
    packages=[package_name],
    data_files=[
        ('share/ament_index/resource_index/packages',
            ['resource/' + package_name]),
        ('share/' + package_name, ['package.xml']),
        (os.path.join('share', package_name), glob('launch/*.launch.py')),
    ],
    install_requires=['setuptools'],
    zip_safe=True,
    maintainer='user',
    maintainer_email='user@todo.todo',
    description='TODO: Package description',
    license='TODO: License declaration',
    tests_require=['pytest'],
    entry_points={
        'console_scripts': [
            'topics_quiz_node = topics_quiz.topics_quiz:main'
        ],
    },
)

From another freshly restarted terminal, while the node is running:

user:~$ source /opt/ros/humble/setup.bashuser:~$ ros2 topic info -v /odom
Type: nav_msgs/msg/Odometry
Publisher count: 1

Node name: turtlebot3_diff_drive
Node namespace: /
Topic type: nav_msgs/msg/Odometry
Endpoint type: PUBLISHER
GID: 01.0f.72.a1.08.01.67.aa.01.00.00.00.00.00.67.03.00.00.00.00.00.00.00.00
QoS profile:
  Reliability: RELIABLE
  History (Depth): UNKNOWN
  Durability: VOLATILE
  Lifespan: Infinite
  Deadline: Infinite
  Liveliness: AUTOMATIC
  Liveliness lease duration: Infinite

Subscription count: 1

Node name: topics_quiz_node

Maybe after staring at this for too long I am overlooking something, but to me the naming appears to be consistent.

[bayodesegun]

Looks ok to me. Just one thing.

Make sure you kill anything running in the terminals before submitting it for grading.

I have added one more trial for you.