launch_launch: Sample program to call a launch file from a launch file (https://ar-ray.hatenablog.com/entry/2021/08/15/203449)

base.launch.py

import launch
import launch_ros.actions

def generate_launch_description():
    param0 = launch.substitutions.LaunchConfiguration('param0', default="0")
    param1 = launch.substitutions.LaunchConfiguration('param1', default="0")
    param2 = launch.substitutions.LaunchConfiguration('param2', default="0")
    param3 = launch.substitutions.LaunchConfiguration('param3', default="0")

    argment0 = launch.actions.DeclareLaunchArgument("param0", default_value="1")
    argment1 = launch.actions.DeclareLaunchArgument("param1", default_value="2")
    argment2 = launch.actions.DeclareLaunchArgument("param2", default_value="3")
    argment3 = launch.actions.DeclareLaunchArgument("param3", default_value="4")

    param_node = launch_ros.actions.Node(
        package="launch_launch", executable="param", output="screen",
        parameters=[{
            "param0": param0,
            "param1": param1,
            "param2": param2,
            "param3": param3,
        }]
    )

    return launch.LaunchDescription([
        argment0,
        argment1,
        # argment2,
        # argment3,

        param_node,
    ])

read_launch.launch.py

import launch
from ament_index_python.packages import get_package_share_directory
from launch.launch_description_sources import PythonLaunchDescriptionSource

def generate_launch_description():
  launch_launch_share_dir = get_package_share_directory("launch_launch")

  read_launch = launch.actions.IncludeLaunchDescription(
    PythonLaunchDescriptionSource([launch_launch_share_dir + "/launch/base.launch.py"]),
      launch_arguments={
          "param0": "10",
          "param1": "20",
          "param2": "30",
          "param3": "40",
      }.items()
  )

  return launch.LaunchDescription([
    read_launch,
  ])