[ROS2] Launch gazebo.launch.py from my own launch file

edit

In ROS1 it was possible with one launch file to start up gazebo, start the robot state publisher, and then spawn the URDF into gazebo. I can't seem to recreate that functionality in ROS2.

My launch file is as follows:

import os
from ament_index_python.packages import get_package_share_directory
from launch import LaunchDescription
from launch.actions import DeclareLaunchArgument, ExecuteProcess
from launch.substitutions import LaunchConfiguration
from launch_ros.actions import Node
from launch.launch_description_sources import PythonLaunchDescriptionSource

def generate_launch_description():

  use_sim_time = LaunchConfiguration('use_sim_time', default='false')
  urdf_file_name = 'urdf/camera_bot.xacro'

  print("urdf_file_name : {}".format(urdf_file_name))

  urdf = os.path.join(
      get_package_share_directory('ros2_sim_pkg'),
      urdf_file_name)

  return LaunchDescription([

        DeclareLaunchArgument(
            'use_sim_time',
            default_value='false',
            description='Use simulation (Gazebo) clock if true'),

        # ExecuteProcess(
        #     cmd=["ros2", "launch", "gazebo_ros", "gazebo.launch.py"]
        # ),

        Node(
            package='robot_state_publisher',
            executable='robot_state_publisher',
            name='robot_state_publisher',
            output='screen',
            parameters=[{'use_sim_time': use_sim_time}],
            arguments=[urdf]),

        Node(
            package='gazebo_ros',
            executable='spawn_entity.py',
            name='urdf_spawner',
            output='screen',
            arguments=["-topic", "/robot_description", "-entity", "cam_bot"])
  ])

You can see my attempt in the commented our ExecuteProcess tag, and I also tried including it through IncludeLaunchDescription and got the same error of: ImportError: cannot import name 'GazeboRosPaths' from 'scripts'

I posted a reply to this thread as well https://github.com/ros-simulation/gazebo_ros_pkgs/issues/1050#issuecomment-809852881

For now I have to get around it by simply launching gazebo manually and then running my launch file in a separate terminal. The exact commands I have in different terminals are as follows: ros2 launch gazebo_ros gazebo.launch.py and ros2 launch ros2_sim_pkg cam_bot_world.launch.py

Surely there is a more streamlined method that I am just unaware of?

If anyone has any insight, it would be greatly appreciated.

Edit: It is worth noting that I am on Ubuntu 20, using ROS2 Foxy, installed from pre-built binaries