Stuck creating moveit::planning_interface::MoveGroupInterface object when launching in a custom namespace

[catmulti7]

Description

Hi everyone,
First I have to say I'm not sure whether this is caused by my mistake or it is a bug. And help will be appreciate.
I'm trying to launch move_group node(from package "moveit_ros_move_group") and move_group_interface node(the node I wrote which uses moveit::planning_interface::MoveGroupInterface to manipulate the robot), I put them in a single launch file(move_group.launch.py) and launch it. It works as expected. But than I create another launch file, include move_group.launch.py and use PushRosNamespace to add a namespace for both nodes, the move_group_interface node stuck at creating moveit::planning_interface::MoveGroupInterface object. There isn't any error information. Programs just hangs there.

Your environment

• ROS Distro: Humble
• OS Version: Ubuntu 22.04
• Source or Binary build? Binary
• If binary, which release version? 2.5.4-1jammy.20230624.062116
• Which RMW (Fast DDS or Cyclone DDS)? Cyclone.

Steps to reproduce

I modify this code and launch file based on hello_moveit package.
move_group.launch

import os
from launch import LaunchDescription
from launch_ros.actions import Node
from launch.actions import ExecuteProcess
from ament_index_python.packages import get_package_share_directory
from moveit_configs_utils import MoveItConfigsBuilder


def generate_launch_description():
    moveit_config = (
        MoveItConfigsBuilder("moveit_resources_panda")
        .robot_description(file_path="config/panda.urdf.xacro")
        .trajectory_execution(file_path="config/gripper_moveit_controllers.yaml")
        .to_moveit_configs()
    )
    # Start the actual move_group node/action server
    run_move_group_node = Node(
        package="moveit_ros_move_group",
        executable="move_group",
        output="screen",
        parameters=[moveit_config.to_dict()],
    )

    move_group_demo = Node(
        name="hello_moveit",
        package="hello_moveit",
        executable="hello_moveit",
        output="screen",
        parameters=[
            moveit_config.robot_description,
            moveit_config.robot_description_semantic,
            moveit_config.robot_description_kinematics,
        ],
    )

    return LaunchDescription(
        [
            run_move_group_node,
            move_group_demo
        ]
    )

move_group_with_ns.launch

import os
from ament_index_python.packages import get_package_share_directory
from launch.actions import IncludeLaunchDescription
from launch import LaunchDescription
from launch.launch_description_sources import PythonLaunchDescriptionSource


from launch.actions import GroupAction
from launch_ros.actions import PushRosNamespace


def generate_launch_description():


    moveit_launch_dir = get_package_share_directory('hello_moveit')

    arm_0_moveit = IncludeLaunchDescription(
        PythonLaunchDescriptionSource(os.path.join(moveit_launch_dir, 'launch', 'move_group.launch.py')))
    
    arm_0_moveit_with_namespace = GroupAction(
     actions=[
         PushRosNamespace('arm_0'),
         arm_0_moveit
      ]
    )

    
    return LaunchDescription([
        arm_0_moveit_with_namespace,
    ])

hello_moveit.cpp

#include <moveit/move_group_interface/move_group_interface.h>
#include <moveit/planning_scene_interface/planning_scene_interface.h>

#include <moveit_msgs/msg/display_robot_state.hpp>
#include <moveit_msgs/msg/display_trajectory.hpp>

#include <moveit_msgs/msg/attached_collision_object.hpp>
#include <moveit_msgs/msg/collision_object.hpp>

#include <moveit_visual_tools/moveit_visual_tools.h>

// All source files that use ROS logging should define a file-specific
// static const rclcpp::Logger named LOGGER, located at the top of the file
// and inside the namespace with the narrowest scope (if there is one)
static const rclcpp::Logger LOGGER = rclcpp::get_logger("move_group_demo");

int main(int argc, char** argv)
{
  rclcpp::init(argc, argv);
  rclcpp::NodeOptions node_options;
  node_options.automatically_declare_parameters_from_overrides(true);
  auto move_group_node = rclcpp::Node::make_shared("move_group_interface_tutorial", node_options);

  rclcpp::executors::SingleThreadedExecutor executor;
  executor.add_node(move_group_node);
  std::thread([&executor]() { executor.spin(); }).detach();


  static const std::string PLANNING_GROUP = "panda_arm";

  moveit::planning_interface::MoveGroupInterface move_group(move_group_node, PLANNING_GROUP);

  rclcpp::shutdown();
  return 0;
}

Expected behaviour

Running ros2 launch hello_moveit move_group_with_ns.launch.py should gives the same output as running ros2 launch hello_moveit move_group.launch.py . Node hello_moveit should finishes automatically.

Actual behaviour

When running ros2 launch hello_moveit move_group_with_ns.launch.py , node hello_moveit never finishes. It seems the constructor of moveit::planning_interface::MoveGroupInterface never return.

Backtrace or Console output

This is what happened when I run ros2 launch hello_moveit move_group.launch.py

[move_group-1] Loading 'move_group/MoveGroupKinematicsService'...
[move_group-1] Loading 'move_group/MoveGroupMoveAction'...
[move_group-1] Loading 'move_group/MoveGroupPlanService'...
[move_group-1] Loading 'move_group/MoveGroupQueryPlannersService'...
[move_group-1] Loading 'move_group/MoveGroupStateValidationService'...
[move_group-1]
[move_group-1] You can start planning now!
[move_group-1]
[hello_moveit-2] [INFO] [1696830269.760325874] [move_group_interface]: Ready to take commands for planning group panda_arm.
[INFO] [hello_moveit-2]: process has finished cleanly [pid 83817]

Running ros2 launch hello_moveit move_group_with_ns.launch.py

[move_group-1] Loading 'move_group/MoveGroupKinematicsService'...
[move_group-1] Loading 'move_group/MoveGroupMoveAction'...
[move_group-1] Loading 'move_group/MoveGroupPlanService'...
[move_group-1] Loading 'move_group/MoveGroupQueryPlannersService'...
[move_group-1] Loading 'move_group/MoveGroupStateValidationService'...
[move_group-1]
[move_group-1] You can start planning now!
[move_group-1]

There is no further output from node hello_moveit.

Thank you for reading this issue and help me.

[catmulti7]

I have figured it out. The constructor of moveit::planning_interface::MoveGroupInterface has another overloaded function which takes the namespace of move_group as a parameter(more accurately, it takes moveit::planning_interface::MoveGroupInterface::Options as a param, which contains the namespace of move_group).
When using custom namespace, create a MoveGroupInterface like this solves above issue

moveit::planning_interface::MoveGroupInterface move_group(
    move_group_node, 
    moveit::planning_interface::MoveGroupInterface::Options(
        PLANNING_GROUP,
        moveit::planning_interface::MoveGroupInterface::ROBOT_DESCRIPTION,
        move_group_namespace));

Note: In my case, string move_group_namespace should have a "/", it should be "/arm_0" rather than "arm_0"