Node stuck at launching when launch with use_sim_time

edit

Publisher Node

import rclpy
from rclpy.node import Node

from std_msgs.msg import String


class MinimalPublisher(Node):

    def __init__(self):
    super().__init__('minimal_publisher')
    self.publisher_ = self.create_publisher(String, 'topic', 10)
    timer_period = 0.5  # seconds
    self.timer = self.create_timer(timer_period, self.timer_callback)
    self.i = 0

    def timer_callback(self):
    msg = String()
    msg.data = 'Hello World: %d' % self.i
    self.publisher_.publish(msg)
    self.get_logger().info('Publishing: "%s"' % msg.data)
    # t  = self._clock.now()

    # self.get_logger().info('The current time is "%s"' % t.to_msg() )
    self.i += 1


def main(args=None):
    rclpy.init(args=args)

    minimal_publisher = MinimalPublisher()

    rclpy.spin(minimal_publisher)

    # Destroy the node explicitly
    # (optional - otherwise it will be done automatically
    # when the garbage collector destroys the node object)
    minimal_publisher.destroy_node()
    rclpy.shutdown()


if __name__ == '__main__':
    main()

Launch File

import launch
import launch_ros.actions
from launch.substitutions import LaunchConfiguration
def generate_launch_description():


    use_sim_time = LaunchConfiguration('use_sim_time', default='true')
    return launch.LaunchDescription([
    launch_ros.actions.Node(
        package='py_pubsub',
        executable='talker',
        name='talker',
        parameters=[{'use_sim_time': use_sim_time}],),
  ])

Platform Ubuntu 20, Galactic

Problem Something I find strange. In my launch file, my talker node works as expected when I don't set 'use_sim_time'. However, once I add the 'use_sim_time' into the launch file. My talker seems stuck during the initalizing stage of launching.

Thus, I am wondering what could cause it go wrong?

Below is what I see in my console when I turn on the console when launching with use_sim_time

shouyu@shouyu-Nitro-AN515-55:~/ros2_ws$ . install/setup.bash 
shouyu@shouyu-Nitro-AN515-55:~/ros2_ws$ ros2 launch py_launch_example my_script_launch.py
[INFO] [launch]: All log files can be found below /home/shouyu/.ros/log/2022-12-27-15-38-19-846893-shouyu-Nitro-AN515-55-93514
[INFO] [launch]: Default logging verbosity is set to INFO
[INFO] [talker-1]: process started with pid [93516]

Global variable

shouyu@shouyu-Nitro-AN515-55:~/ros2_ws$ env | grep ROS

ROS_VERSION=2
ROS_PYTHON_VERSION=3
ROS_LOCALHOST_ONLY=0
ROS_DISTRO=galactic

```