#!/usr/bin/env python3
"""
Launch file for bridging Modern Gazebo services to ROS2.
This launch file starts ros_gz_bridge to expose Modern Gazebo (Ignition)
services as ROS2 services, enabling the Modern Gazebo adapter to function.
Services bridged:
- /world/{world}/create - Spawn entities
- /world/{world}/remove - Delete entities
- /world/{world}/set_pose - Set entity poses
- /world/{world}/control - Control simulation (pause/unpause/reset)
Usage:
ros2 launch gazebo_mcp gazebo_bridge.launch.py world_name:=empty
"""
import os
from launch import LaunchDescription
from launch.actions import DeclareLaunchArgument, OpaqueFunction
from launch.substitutions import LaunchConfiguration
from launch_ros.actions import Node
def launch_bridge(context, *args, **kwargs):
"""Launch bridge with world name from context."""
# Get world name from launch configuration
world_name = context.launch_configurations.get('world_name', 'default')
# Bridge configuration for services
# Format: service@ROS2_srv_type
bridge_config = [
# Spawn entity service
f'/world/{world_name}/create@ros_gz_interfaces/srv/SpawnEntity',
# Delete entity service
f'/world/{world_name}/remove@ros_gz_interfaces/srv/DeleteEntity',
# Set entity pose service
f'/world/{world_name}/set_pose@ros_gz_interfaces/srv/SetEntityPose',
# Control world service (pause, unpause, reset)
f'/world/{world_name}/control@ros_gz_interfaces/srv/ControlWorld',
# Pose information topic (Gazebo -> ROS2)
f'/world/{world_name}/pose/info[ros_gz_interfaces/msg/ParamVec',
# Clock topic (Gazebo -> ROS2)
'/clock[rosgraph_msgs/msg/Clock',
]
# Create ros_gz_bridge node
bridge_node = Node(
package='ros_gz_bridge',
executable='parameter_bridge',
name='gazebo_ros_bridge',
output='screen',
parameters=[{
'use_sim_time': True,
}],
arguments=bridge_config,
)
return [bridge_node]
def generate_launch_description():
"""Generate launch description for Gazebo bridge."""
# Declare launch arguments
world_name_arg = DeclareLaunchArgument(
'world_name',
default_value='default',
description='Name of the Gazebo world to bridge'
)
return LaunchDescription([
world_name_arg,
OpaqueFunction(function=launch_bridge),
])
