runtime/rbs_bringup/launch/simulation.launch.py

import os
from launch_ros.actions import Node
from launch import LaunchDescription
from launch.actions import DeclareLaunchArgument, IncludeLaunchDescription
from launch_ros.substitutions import FindPackageShare
from launch.substitutions import Command, FindExecutable, LaunchConfiguration, PathJoinSubstitution
from launch.conditions import IfCondition
from launch.launch_description_sources import PythonLaunchDescriptionSource
from ament_index_python.packages import get_package_share_directory


def generate_launch_description():
    declared_arguments = []
    declared_arguments.append(
        DeclareLaunchArgument("sim_gazebo", default_value="false", description="Gazebo Simulation")
    )
    declared_arguments.append(
        DeclareLaunchArgument(
            "rbs_robot_type",
            description="Type of robot by name",
            choices=["ur3", "ur3e", "ur5", "ur5e", "ur10", "ur10e", "ur16e"],
            default_value="ur5e",
        )
    )
    declared_arguments.append(
        DeclareLaunchArgument("env_manager", default_value="false", description="Launch env_manager?")
    )
    
    sim_gazebo = LaunchConfiguration("sim_gazebo")
    rbs_robot_type = LaunchConfiguration("rbs_robot_type")
    env_manager_cond = LaunchConfiguration("env_manager")

    # FIXME: To args when we'll have different files
    world_config_file = PathJoinSubstitution(
        [FindPackageShare("rbs_simulation"), "worlds", "mir.sdf"]
    )
    # Gazebo nodes
    gazebo = IncludeLaunchDescription(
            PythonLaunchDescriptionSource(
                [os.path.join(get_package_share_directory('ros_ign_gazebo'),
                              'launch', 'ign_gazebo.launch.py')]),
                launch_arguments=[('ign_args', [' -r ',world_config_file, " --physics-engine ignition-physics-dartsim-plugin --render-engine ogre2"])],
                condition=IfCondition(sim_gazebo))
    # Spawn robot
    gazebo_spawn_robot = Node(package='ros_ign_gazebo', executable='create',
                 arguments=[
                    '-name', rbs_robot_type,
                    '-x', '0.0',
                    '-z', '0.0',
                    '-y', '0.0',
                    '-topic', '/robot_description'],
                 output='screen',
                 condition=IfCondition(sim_gazebo))
    
    env_manager = Node(package="env_manager", 
                       executable="env_manager_node",
                       condition=IfCondition(env_manager_cond)
                       )

    nodes_to_start = [
        gazebo,
        gazebo_spawn_robot,
        env_manager
    ]
    return LaunchDescription(declared_arguments + nodes_to_start)