# Create a new ROS2 package
ros2 pkg create --build-type ament_python my_robot_pkg \
  --dependencies rclpy std_msgs sensor_msgs geometry_msgs

# For C++ packages
ros2 pkg create --build-type ament_cmake my_robot_cpp_pkg \
  --dependencies rclcpp std_msgs sensor_msgs

my_robot_pkg/
├── my_robot_pkg/
│   ├── __init__.py
│   ├── my_node.py
│   └── utils/
├── launch/
│   └── robot_launch.py
├── config/
│   └── params.yaml
├── resource/
│   └── my_robot_pkg
├── test/
├── package.xml
├── setup.py
└── setup.cfg

from launch import LaunchDescription
from launch_ros.actions import Node
from launch.actions import DeclareLaunchArgument
from launch.substitutions import LaunchConfiguration
from ament_index_python.packages import get_package_share_directory
import os

def generate_launch_description():
    # Get package share directory
    pkg_share = get_package_share_directory('my_robot_pkg')

    # Declare launch arguments
    use_sim_time = DeclareLaunchArgument(
        'use_sim_time',
        default_value='false',
        description='Use simulation time'
    )

    # Node configuration
    robot_node = Node(
        package='my_robot_pkg',
        executable='my_node',
        name='robot_controller',
        output='screen',
        parameters=[
            os.path.join(pkg_share, 'config', 'params.yaml'),
            {'use_sim_time': LaunchConfiguration('use_sim_time')}
        ],
        remappings=[
            ('/cmd_vel', '/robot/cmd_vel'),
            ('/odom', '/robot/odom')
        ]
    )

    return LaunchDescription([
        use_sim_time,
        robot_node
    ])

import rclpy
from rclpy.node import Node
from rclpy.qos import QoSProfile, ReliabilityPolicy, HistoryPolicy
from std_msgs.msg import String
from geometry_msgs.msg import Twist
from sensor_msgs.msg import LaserScan

class RobotController(Node):
    def __init__(self):
        super().__init__('robot_controller')

        # Declare parameters
        self.declare_parameter('max_speed', 1.0)
        self.declare_parameter('safety_distance', 0.5)

        # QoS profile for sensor data
        sensor_qos = QoSProfile(
            reliability=ReliabilityPolicy.BEST_EFFORT,
            history=HistoryPolicy.KEEP_LAST,
            depth=10
        )

        # Publishers
        self.cmd_vel_pub = self.create_publisher(
            Twist, '/cmd_vel', 10
        )

        # Subscribers
        self.laser_sub = self.create_subscription(
            LaserScan, '/scan', self.laser_callback, sensor_qos
        )

        # Timer for control loop
        self.timer = self.create_timer(0.1, self.control_loop)

        self.get_logger().info('Robot controller initialized')

    def laser_callback(self, msg):
        # Process laser scan data
        self.latest_scan = msg

    def control_loop(self):
        # Main control logic
        max_speed = self.get_parameter('max_speed').value
        # ... control logic ...

def main(args=None):
    rclpy.init(args=args)
    node = RobotController()
    rclpy.spin(node)
    node.destroy_node()
    rclpy.shutdown()

if __name__ == '__main__':
    main()

# msg/RobotStatus.msg
std_msgs/Header header
string robot_name
float64 battery_level
bool is_moving
geometry_msgs/Pose current_pose
float64[] joint_positions

# srv/SetMode.srv
string mode
---
bool success
string message

# action/Navigate.action
# Goal
geometry_msgs/PoseStamped target_pose
float64 timeout
---
# Result
bool success
string message
float64 elapsed_time
---
# Feedback
float64 distance_remaining
float64 estimated_time_remaining

from rclpy.qos import QoSProfile, QoSReliabilityPolicy, QoSHistoryPolicy, QoSDurabilityPolicy

# Sensor data (high frequency, lossy)
sensor_qos = QoSProfile(
    reliability=QoSReliabilityPolicy.BEST_EFFORT,
    history=QoSHistoryPolicy.KEEP_LAST,
    depth=5
)

# Control commands (reliable)
control_qos = QoSProfile(
    reliability=QoSReliabilityPolicy.RELIABLE,
    history=QoSHistoryPolicy.KEEP_LAST,
    depth=10
)

# Parameters and configuration (transient local)
config_qos = QoSProfile(
    reliability=QoSReliabilityPolicy.RELIABLE,
    durability=QoSDurabilityPolicy.TRANSIENT_LOCAL,
    history=QoSHistoryPolicy.KEEP_LAST,
    depth=1
)

# List all nodes
ros2 node list

# Get node info
ros2 node info /robot_controller

# List topics
ros2 topic list -t

# Echo topic
ros2 topic echo /cmd_vel

# Topic bandwidth/frequency
ros2 topic hz /scan
ros2 topic bw /camera/image_raw

# Service list and call
ros2 service list
ros2 service call /set_mode my_robot_pkg/srv/SetMode "{mode: 'autonomous'}"

# Parameter operations
ros2 param list /robot_controller
ros2 param get /robot_controller max_speed
ros2 param set /robot_controller max_speed 2.0

# TF2 debugging
ros2 run tf2_tools view_frames
ros2 run tf2_ros tf2_echo base_link odom

{
  "operation": "create-package",
  "packageName": "my_robot_pkg",
  "buildType": "ament_python",
  "status": "success",
  "artifacts": [
    "my_robot_pkg/package.xml",
    "my_robot_pkg/setup.py",
    "my_robot_pkg/my_robot_pkg/__init__.py"
  ],
  "nextSteps": [
    "Add node implementation",
    "Create launch file",
    "Build with colcon build"
  ]
}