ros2-development: Скилл для разработки и отладки ROS2

--- name: ros2-development description: > Comprehensive best practices, design patterns, and common pitfalls for ROS2 (Robot Operating System 2) development. Use this skill when building ROS2 nodes, packages, launch files, components, or debugging ROS2 systems. Trigger whenever the user mentions ROS2, colcon, rclpy, rclcpp, DDS, QoS, lifecycle nodes, managed nodes, ROS2 launch, ROS2 parameters, ROS2 actions, nav2, MoveIt2, micro-ROS, or any ROS2-era robotics middleware. Also trigger for ROS2 workspace setup, DDS tuning, intra-process communication, ROS2 security, or deploying ROS2 in production. Also trigger for colcon build issues, ament_cmake, ament_python, CMakeLists.txt for ROS2, package.xml dependencies, rosdep, workspace overlays, custom message generation, or ROS2 build troubleshooting. Covers Humble, Iron, Jazzy, and Rolling distributions. --- # ROS2 Development Skill ## When to Use This Skill - Building ROS2 packages, nodes, or component containers - Setting up colcon workspaces, ament_cmake, or ament_python packages - Writing CMakeLists.txt, package.xml, or setup.py for ROS2 - Defining custom messages, services, or actions - Writing Python launch files with conditional logic - Configuring DDS middleware and QoS profiles - Implementing lifecycle (managed) nodes - Working with Nav2, MoveIt2, or other ROS2 frameworks - Debugging DDS discovery, QoS mismatches, or build failures - Deploying ROS2 to production or embedded systems (micro-ROS) - Setting up CI/CD for ROS2 packages ## Core Architecture ### 1. Node Design Patterns **Basic Node (rclpy)**: ```python #!/usr/bin/env python3 import rclpy from rclpy.node import Node from rclpy.qos import QoSProfile, ReliabilityPolicy, HistoryPolicy from std_msgs.msg import String class PerceptionNode(Node): def __init__(self): super().__init__('perception_node') # 1. Declare parameters with types and descriptions self.declare_parameter('rate_hz', 30.0, descriptor=ParameterDescriptor( description='Processing rate in Hz', floating_point_range=[FloatingPointRange( from_value=1.0, to_value=120.0, step=0.0 )] )) self.declare_parameter('confidence_threshold', 0.7) self.declare_parameter('frame_id', 'camera_link') # 2. Read parameters rate_hz = self.get_parameter('rate_hz').value self.threshold = self.get_parameter('confidence_threshold').value self.frame_id = self.get_parameter('frame_id').value # 3. Set up QoS profiles sensor_qos = QoSProfile( reliability=ReliabilityPolicy.BEST_EFFORT, history=HistoryPolicy.KEEP_LAST, depth=1 ) reliable_qos = QoSProfile( reliability=ReliabilityPolicy.RELIABLE, history=HistoryPolicy.KEEP_LAST, depth=10 ) # 4. Publishers first, then subscribers self.det_pub = self.create_publisher( DetectionArray, 'detections', reliable_qos) self.image_sub = self.create_subscription( Image, 'camera/image_raw', self.image_callback, sensor_qos) # 5. Timers for periodic work self.timer = self.create_timer(1.0 / rate_hz, self.timer_callback) # 6. Parameter change callback self.add_on_set_parameters_callback(self.param_callback) self.get_logger().info( f'Perception node started at {rate_hz}Hz, ' f'threshold={self.threshold}') def param_callback(self, params): """Handle runtime parameter changes (replaces dynamic_reconfigure)""" for param in params: if param.name == 'confidence_threshold': self.threshold = param.value self.get_logger().info(f'Threshold updated to {param.value}') return SetParametersResult(successful=True) def image_callback(self, msg): # Process incoming images pass def timer_callback(self): # Periodic work pass def main(args=None): rclpy.init(args=args) node = PerceptionNode() try: rclpy.spin(node) except KeyboardInterrupt: pass finally: node.destroy_node() rclpy.shutdown() if __name__ == '__main__': main() ``` **Basic Node (rclcpp)**: ```cpp #include <rclcpp/rclcpp.hpp> #include <sensor_msgs/msg/image.hpp> #include <vision_msgs/msg/detection2_d.hpp> #include <memory> class PerceptionNode : public rclcpp::Node { public: PerceptionNode() : Node("perception_node") { // Declare and get parameters this->declare_parameter("rate_hz", 30.0); this->declare_parameter("confidence_threshold", 0.7); double rate_hz = this->get_parameter("rate_hz").as_double(); // QoS auto sensor_qos = rclcpp::SensorDataQoS(); auto reliable_qos = rclcpp::QoS(10).reliable(); // Publishers and subscribers det_pub_ = this->create_publisher<vision_msgs::msg::Detection2D>("detections", reliable_qos); image_sub_ = this->create_subscription<sensor_msgs::msg::Image>( "camera/image_raw", sensor_qos, [this](const std::shared_ptr<const sensor_msgs::msg::Image>& msg){ this->image_callback(msg); }); timer_ = this->create_wall_timer( std::chrono::milliseconds(static_cast<int>(1000.0 / rate_hz)), [this](){ this->timer_callback(); }); RCLCPP_INFO(this->get_logger(), "Perception node started at %.1fHz", rate_hz); } private: void image_callback(const std::shared_ptr<const sensor_msgs::msg::Image>& msg) { // Use shared_ptr for zero-copy potential } void timer_callback() {} rclcpp::Publisher<vision_msgs::msg::Detection2D>::SharedPtr det_pub_; rclcpp::Subscription<sensor_msgs::msg::Image>::SharedPtr image_sub_; rclcpp::TimerBase::SharedPtr timer_; }; int main(int argc, char** argv) { rclcpp::init(argc, argv); rclcpp::spin(std::make_shared<PerceptionNode>()); rclcpp::shutdown(); return 0; } ``` ### 2. Lifecycle (Managed) Nodes Use lifecycle nodes for production systems where you need deterministic startup, shutdown, and error recovery. This is one of ROS2's most important features over ROS1. **State Machine**: `Unconfigured → Inactive → Active → Finalized` ```python from rclpy.lifecycle import Node as LifecycleNode, TransitionCallbackReturn class ManagedPerception(LifecycleNode): def __init__(self): super().__init__('managed_perception') self.get_logger().info('Node created (unconfigured)') def on_configure(self, state) -> TransitionCallbackReturn: """Load params, allocate memory, set up pubs/subs (but don't activate)""" self.declare_parameter('model_path', '') model_path = self.get_parameter('model_path').value try: self.model = load_model(model_path) self.det_pub = self.create_lifecycle_publisher( DetectionArray, 'detections', 10) self.get_logger().info(f'Configured with model: {model_path}') return TransitionCallbackReturn.SUCCESS except Exception as e: self.get_logger().error(f'Configuration failed: {e}') return TransitionCallbackReturn.FAILURE def on_activate(self, state) -> TransitionCallbackReturn: """Start processing — subscriptions go live here""" self.image_sub = self.create_subscription( Image, 'camera/image_raw', self.image_callback, 1) self.get_logger().info('Activated — processing images') return TransitionCallbackReturn.SUCCESS def on_deactivate(self, state) -> TransitionCallbackReturn: """Pause processing — safe to reconfigure after this""" self.destroy_subscription(self.image_sub) self.get_logger().info('Deactivated — stopped processing') return TransitionCallbackReturn.SUCCESS def on_cleanup(self, state) -> TransitionCallbackReturn: """Release resources, return to unconfigured""" del self.model self.get_logger().info('Cleaned up') return TransitionCallbackReturn.SUCCESS def on_shutdown(self, state) -> TransitionCallbackReturn: """Final cleanup before destruction""" self.get_logger().info('Shutting down') return TransitionCallbackReturn.SUCCESS def on_error(self, state) -> TransitionCallbackReturn: """Handle errors — try to recover or fail gracefully""" self.get_logger().error(f'Error in state {state.label}') return TransitionCallbackReturn.SUCCESS # Transition to unconfigured ``` **Orchestrating Lifecycle Nodes** with a launch file: ```python from launch import LaunchDescription from launch_ros.actions import LifecycleNode from launch_ros.event_handlers import OnStateTransition from launch.actions import EmitEvent, RegisterEventHandler from launch_ros.events.lifecycle import ChangeState from lifecycle_msgs.msg import Transition def generate_launch_description(): perception = LifecycleNode( package='my_pkg', executable='managed_perception', name='perception', output='screen', parameters=[{'model_path': '/models/yolo.pt'}] ) # Auto-configure on startup configure_event = EmitEvent(event=ChangeState( lifecycle_node_matcher=lambda node: node == perception, transition_id=Transition.TRANSITION_CONFIGURE )) # Auto-activate after successful configure activate_handler = RegisterEventHandler(OnStateTransition( target_lifecycle_node=perception, goal_state='inactive', entities=[EmitEvent(event=ChangeState( lifecycle_node_matcher=lambda node: node == perception, transition_id=Transition.TRANSITION_ACTIVATE ))] )) return LaunchDescription([ perception, configure_event, activate_handler, ]) ``` ### 3. QoS (Quality of Service) — The #1 Source of ROS2 Bugs QoS mismatches are the most common reason topics silently fail to connect. **QoS Compatibility Matrix**: ``` Publisher Subscriber Compatible? RELIABLE RELIABLE ✅ Yes RELIABLE BEST_EFFORT ✅ Yes BEST_EFFORT BEST_EFFORT ✅ Yes BEST_EFFORT RELIABLE ❌ NO — SILENT FAILURE ``` **Recommended QoS Profiles by Use Case**: ```python from rclpy.qos import ( QoSProfile, QoSReliabilityPolicy, QoSHistoryPolicy, QoSDurabilityPolicy, QoSPresetProfiles ) # Sensor data (cameras, lidars) — tolerate drops, want latest SENSOR_QOS = QoSProfile( reliability=QoSReliabilityPolicy.BEST_EFFORT, history=QoSHistoryPolicy.KEEP_LAST, depth=1, durability=QoSDurabilityPolicy.VOLATILE ) # Commands (velocity, joint) — never miss, small buffer COMMAND_QOS = QoSProfile( reliability=QoSReliabilityPolicy.RELIABLE, history=QoSHistoryPolicy.KEEP_LAST, depth=10, durability=QoSDurabilityPolicy.VOLATILE ) # Map / static data — reliable, and late joiners get it MAP_QOS = QoSProfile( reliability=QoSReliabilityPolicy.RELIABLE, history=QoSHistoryPolicy.KEEP_LAST, depth=1, durability=QoSDurabilityPolicy.TRANSIENT_LOCAL # Replaces ROS1 latch ) # Default parameter/state — reliable with some history STATE_QOS = QoSProfile( reliability=QoSReliabilityPolicy.RELIABLE, history=QoSHistoryPolicy.KEEP_LAST, depth=10 ) ``` **Debugging QoS Issues**: ```bash # Check QoS info for a topic ros2 topic info /camera/image_raw -v # Look for "Reliability" and "Durability" fields # Check for incompatible QoS events ros2 run rqt_topic rqt_topic # Shows sub counts and QoS # If 0 subscribers despite nodes running: QoS MISMATCH ``` ### 4. Launch Files (Python-Based) ROS2 launch files are Python, enabling powerful conditional logic: ```python import os from launch import LaunchDescription from launch.actions import ( DeclareLaunchArgument, IncludeLaunchDescription, GroupAction, OpaqueFunction, TimerAction ) from launch.conditions import IfCondition, UnlessCondition from launch.substitutions import ( LaunchConfiguration, PathJoinSubstitution, PythonExpression ) from launch_ros.actions import Node, ComposableNodeContainer, LoadComposableNode from launch_ros.descriptions import ComposableNode from launch_ros.substitutions import FindPackageShare def generate_launch_description(): # Arguments robot_name_arg = DeclareLaunchArgument('robot_name', default_value='ur5') sim_arg = DeclareLaunchArgument('sim', default_value='false') use_composition_arg = DeclareLaunchArgument('use_composition', default_value='true') robot_name = LaunchConfiguration('robot_name') sim = LaunchConfiguration('sim') # Load YAML params config_file = PathJoinSubstitution([ FindPackageShare('my_pkg'), 'config', 'robot_params.yaml' ]) # Standard node perception_node = Node( package='my_pkg', executable='perception_node', name='perception', namespace=robot_name, parameters=[config_file, {'use_sim_time': sim}], remappings=[ ('camera/image_raw', 'realsense/color/image_raw'), ('detections', 'perception/detections'), ], output='screen', condition=UnlessCondition(LaunchConfiguration('use_composition')), ) # Composable nodes (zero-copy, same process) composable_container = ComposableNodeContainer( name='perception_container', namespace=robot_name, package='rclcpp_components', executable='component_container_mt', # Multi-threaded composable_node_descriptions=[ ComposableNode( package='my_pkg', plugin='my_pkg::PerceptionComponent', name='perception', parameters=[config_file], remappings=[ ('camera/image_raw', 'realsense/color/image_raw'), ], ), ComposableNode( package='my_pkg', plugin='my_pkg::TrackerComponent', name='tracker', ), ], condition=IfCondition(LaunchConfiguration('use_composition')), ) # Delayed start for nodes that need others to initialize first delayed_planner = TimerAction( period=3.0, actions=[ Node(package='my_pkg', executable='planner_node', name='planner') ] ) return LaunchDescription([ robot_name_arg, sim_arg, use_composition_arg, perception_node, composable_container, delayed_planner, ]) ``` ### 5. Components (ROS2's Answer to Nodelets) ```cpp #include <rclcpp/rclcpp.hpp> #include <rclcpp_components/register_node_macro.hpp> #include <sensor_msgs/msg/image.hpp> namespace my_pkg { class PerceptionComponent : public rclcpp::Node { public: explicit PerceptionComponent(const rclcpp::NodeOptions& options) : Node("perception", options) { // Use intra-process communication for zero-copy auto sub_options = rclcpp::SubscriptionOptions(); sub_options.use_intra_process_comm = rclcpp::IntraProcessSetting::Enable; sub_ = this->create_subscription<sensor_msgs::msg::Image>( "camera/image_raw", rclcpp::SensorDataQoS(), [this](sensor_msgs::msg::Image::UniquePtr msg) { this->callback(std::move(msg)); }, sub_options); } private: void callback(sensor_msgs::msg::Image::UniquePtr msg) { // UniquePtr = zero-copy when: // - publisher also uses UniquePtr // - both subscriber and publisher use intra-process // - this is the only subscriber // msg is moved, not copied } rclcpp::Subscription<sensor_msgs::msg::Image>::SharedPtr sub_; }; } // namespace my_pkg RCLCPP_COMPONENTS_REGISTER_NODE(my_pkg::PerceptionComponent) ``` ### 6. Actions (ROS2 Style) ```python from rclpy.action import ActionServer, CancelResponse, GoalResponse from my_interfaces.action import PickPlace class PickPlaceServer(Node): def __init__(self): super().__init__('pick_place_server') self._action_server = ActionServer( self, PickPlace, 'pick_place', execute_callback=self.execute_cb, goal_callback=self.goal_cb, cancel_callback=self.cancel_cb, ) def goal_cb(self, goal_request): """Decide whether to accept or reject the goal""" self.get_logger().info(f'Received goal: {goal_request.target_pose}') return GoalResponse.ACCEPT def cancel_cb(self, goal_handle): """Decide whether to accept cancel requests""" self.get_logger().info('Cancel requested') return CancelResponse.ACCEPT async def execute_cb(self, goal_handle): """Execute the action (runs in an executor thread)""" feedback_msg = PickPlace.Feedback() for i, step in enumerate(self.plan(goal_handle.request)): # Check cancellation if goal_handle.is_cancel_requested: goal_handle.canceled() return PickPlace.Result(success=False) self.execute_step(step) feedback_msg.progress = float(i) / len(self.steps) goal_handle.publish_feedback(feedback_msg) goal_handle.succeed() return PickPlace.Result(success=True) ``` ## DDS Configuration ### Choosing a DDS Implementation ```bash # Set DDS middleware (in ~/.bashrc or launch) export RMW_IMPLEMENTATION=rmw_cyclonedds_cpp # Recommended for most cases # export RMW_IMPLEMENTATION=rmw_fastrtps_cpp # Default, good for multi-machine # Limit DDS discovery to local machine (reduces network noise) export ROS_LOCALHOST_ONLY=1 # Use ROS_DOMAIN_ID to isolate robot groups on same network export ROS_DOMAIN_ID=42 # Range 0-101 ``` ### CycloneDDS Tuning (cyclonedds.xml) ```xml <?xml version="1.0" encoding="UTF-8"?> <CycloneDDS xmlns="https://cdds.io/config"> <Domain> <General> <NetworkInterfaceAddress>eth0</NetworkInterfaceAddress> <AllowMulticast>false</AllowMulticast> <!-- Unicast for reliability --> </General> <Internal> <MaxMessageSize>65500</MaxMessageSize> <SocketReceiveBufferSize>10MB</SocketReceiveBufferSize> </Internal> <!-- For large data (images, point clouds) --> <Sizing> <ReceiveBufferSize>10MB</ReceiveBufferSize> </Sizing> </Domain> </CycloneDDS> ``` ```bash export CYCLONEDDS_URI=file:///path/to/cyclonedds.xml ``` ## Build System ### Workspace Setup and colcon ```bash # Create a ROS2 workspace mkdir -p ~/ros2_ws/src cd ~/ros2_ws # Clone packages into src/ cd src git clone https://github.com/org/my_robot_pkg.git cd .. # Install dependencies declared in package.xml files sudo apt update rosdep update rosdep install --from-paths src --ignore-src -y # Build the workspace source /opt/ros/humble/setup.bash # Source the ROS2 underlay FIRST colcon build # Source the workspace overlay source install/setup.bash ``` **Essential colcon flags**: ```bash # Build only specific packages (faster iteration) colcon build --packages-select my_pkg # Build a package and all its dependencies colcon build --packages-up-to my_pkg # Symlink Python files instead of copying (edit without rebuild) colcon build --symlink-install # Parallel jobs (default = nproc, lower if running out of RAM) colcon build --parallel-workers 4 # Pass CMake args to all packages colcon build --cmake-args -DCMAKE_BUILD_TYPE=Release # Clean build (remove build/ install/ log/ and rebuild) rm -rf build/ install/ log/ colcon build # Build with compiler warnings as errors (CI) colcon build --cmake-args -DCMAKE_CXX_FLAGS="-Wall -Werror" # Show build output in real-time (useful for debugging build failures) colcon build --event-handlers console_direct+ ``` ### Build Types: ament_cmake vs ament_python Choose based on your package language: ``` ament_cmake — C++ packages, mixed C++/Python packages, packages with custom msgs ament_python — Pure Python packages (no C++, no custom messages) ``` ### package.xml — Declaring Dependencies ```xml <?xml version="1.0"?> <?xml-model href="http://download.ros.org/schema/package_format3.xsd" schematypens="http://www.w3.org/2001/XMLSchema"?> <package format="3"> <name>my_robot_pkg</name> <version>0.1.0</version> <description>My robot perception package</description> <maintainer email="dev@example.com">Dev Name</maintainer> <license>Apache-2.0</license> <!-- Build tool — determines build type --> <buildtool_depend>ament_cmake</buildtool_depend> <!-- For pure Python: <buildtool_depend>ament_python</buildtool_depend> --> <!-- Build-time dependencies (headers, CMake modules) --> <build_depend>rclcpp</build_depend> <build_depend>sensor_msgs</build_depend> <build_depend>OpenCV</build_depend> <!-- Runtime dependencies --> <exec_depend>rclcpp</exec_depend> <exec_depend>sensor_msgs</exec_depend> <exec_depend>rclpy</exec_depend> <!-- Shortcut: depend = build_depend + exec_depend --> <depend>rclcpp</depend> <depend>sensor_msgs</depend> <depend>geometry_msgs</depend> <depend>tf2_ros</depend> <depend>cv_bridge</depend> <!-- For custom message generation --> <build_depend>rosidl_default_generators</build_depend> <exec_depend>rosidl_default_runtime</exec_depend> <member_of_group>rosidl_interface_packages</member_of_group> <!-- Test dependencies --> <test_depend>ament_lint_auto</test_depend> <test_depend>ament_cmake_pytest</test_depend> <test_depend>launch_testing_ament_cmake</test_depend> <export> <build_type>ament_cmake</build_type> </export> </package> ``` ### CMakeLists.txt — ament_cmake Package ```cmake cmake_minimum_required(VERSION 3.8) project(my_robot_pkg) # Default to C++17 if(NOT CMAKE_CXX_STANDARD) set(CMAKE_CXX_STANDARD 17) endif() if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang") add_compile_options(-Wall -Wextra -Wpedantic) endif() # ── Find dependencies ────────────────────────────────────────── find_package(ament_cmake REQUIRED) find_package(rclcpp REQUIRED) find_package(rclcpp_components REQUIRED) find_package(sensor_msgs REQUIRED) find_package(geometry_msgs REQUIRED) find_package(tf2_ros REQUIRED) find_package(cv_bridge REQUIRED) find_package(OpenCV REQUIRED) # ── Custom messages / services / actions ─────────────────────── find_package(rosidl_default_generators REQUIRED) rosidl_generate_interfaces(${PROJECT_NAME} "msg/Detection.msg" "srv/GetPose.srv" "action/PickPlace.action" DEPENDENCIES geometry_msgs sensor_msgs ) # ── Standalone executable node ───────────────────────────────── add_executable(perception_node src/perception_node.cpp) ament_target_dependencies(perception_node rclcpp sensor_msgs cv_bridge OpenCV tf2_ros ) install(TARGETS perception_node DESTINATION lib/${PROJECT_NAME} ) # ── Component (composable node) ──────────────────────────────── add_library(perception_component SHARED src/perception_component.cpp ) ament_target_dependencies(perception_component rclcpp rclcpp_components sensor_msgs cv_bridge OpenCV ) # Register as a composable node rclcpp_components_register_node(perception_component PLUGIN "my_robot_pkg::PerceptionComponent" EXECUTABLE perception_component_node ) install(TARGETS perception_component ARCHIVE DESTINATION lib LIBRARY DESTINATION lib RUNTIME DESTINATION bin ) # ── Install Python nodes ─────────────────────────────────────── install(PROGRAMS scripts/planning_node.py DESTINATION lib/${PROJECT_NAME} ) # ── Install launch, config, rviz, urdf ───────────────────────── install(DIRECTORY launch config rviz urdf DESTINATION share/${PROJECT_NAME} ) # ── Install headers ──────────────────────────────────────────── install(DIRECTORY include/ DESTINATION include ) # ── Tests ────────────────────────────────────────────────────── if(BUILD_TESTING) find_package(ament_lint_auto REQUIRED) ament_lint_auto_find_test_dependencies() find_package(ament_cmake_pytest REQUIRED) ament_add_pytest_test(test_perception test/test_perception.py) find_package(launch_testing_ament_cmake REQUIRED) add_launch_test(test/test_integration.py) endif() ament_package() ``` ### setup.py / setup.cfg — Pure Python Package ```python # setup.py (for ament_python packages) from setuptools import find_packages, setup package_name = 'my_python_pkg' setup( name=package_name, version='0.1.0', packages=find_packages(exclude=['test']), data_files=[ # Register with ament index ('share/ament_index/resource_index/packages', ['resource/' + package_name]), # Package manifest ('share/' + package_name, ['package.xml']), # Launch files ('share/' + package_name + '/launch', ['launch/robot.launch.py']), # Config files ('share/' + package_name + '/config', ['config/params.yaml']), ], install_requires=['setuptools'], zip_safe=True, maintainer='Dev Name', maintainer_email='dev@example.com', description='My Python robot package', license='Apache-2.0', entry_points={ 'console_scripts': [ # format: 'executable_name = package.module:function' 'perception_node = my_python_pkg.perception_node:main', 'planner_node = my_python_pkg.planner_node:main', ], }, ) ``` ```cfg # setup.cfg [develop] script_dir=$base/lib/my_python_pkg [install] install_scripts=$base/lib/my_python_pkg ``` ### Custom Message, Service, and Action Definitions ``` # msg/Detection.msg std_msgs/Header header string class_name float32 confidence geometry_msgs/Pose pose float32[4] bbox # [x_min, y_min, x_max, y_max] ``` ``` # srv/GetPose.srv string object_name --- bool success geometry_msgs/PoseStamped pose string error_message ``` ``` # action/PickPlace.action # Goal geometry_msgs/Pose target_pose string object_class --- # Result bool success string error_message --- # Feedback float32 progress string current_phase ``` ### Workspace Overlays ``` Underlay (base ROS2) /opt/ros/humble/ ↑ Overlay 1 (shared libs) ~/ros2_ws/install/ ↑ Overlay 2 (your dev pkg) ~/dev_ws/install/ Source order matters — LAST sourced overlay wins for duplicate packages. ``` ```bash # Correct source order source /opt/ros/humble/setup.bash # Base source ~/ros2_ws/install/setup.bash # Shared workspace source ~/dev_ws/install/setup.bash # Your development overlay # NEVER source setup.bash from build/ — always use install/ ``` ### Build Troubleshooting ```bash # "Package not found" during build # → Missing dependency. Check package.xml and run: rosdep install --from-paths src --ignore-src -y # "Could not find a package configuration file provided by X" # → CMake can't find the package. Did you source the underlay? source /opt/ros/humble/setup.bash # Build succeeds but node can't be found at runtime # → Forgot to source the overlay, or entry_points misconfigured source install/setup.bash ros2 pkg list | grep my_pkg # Should appear ros2 pkg executables my_pkg # List available executables # Python changes not reflected after rebuild # → Use --symlink-install, or clean and rebuild colcon build --packages-select my_pkg --symlink-install # "Multiple packages with the same name" # → Duplicate package in workspace. Check with: colcon list --packages-select my_pkg # Build runs out of memory (large C++ packages) colcon build --parallel-workers 2 --executor sequential # Custom messages not found by Python nodes # → Missing rosidl_default_runtime in package.xml exec_depend # → Or forgot to source install/setup.bash after building msgs ``` ## Package Structure (ROS2) ``` my_robot_pkg/ ├── CMakeLists.txt # Or setup.py for pure Python ├── package.xml ├── my_robot_pkg/ # Python module (same name as package) │ ├── __init__.py │ ├── perception_node.py │ └── utils/ │ └── transforms.py ├── src/ # C++ source │ └── perception_component.cpp ├── include/my_robot_pkg/ # C++ headers │ └── perception_component.hpp ├── config/ │ ├── robot_params.yaml │ └── cyclonedds.xml ├── launch/ │ ├── robot.launch.py │ └── perception.launch.py ├── msg/ │ └── Detection.msg ├── srv/ │ └── GetPose.srv ├── action/ │ └── PickPlace.action ├── rviz/ │ └── robot.rviz ├── urdf/ │ └── robot.urdf.xacro └── test/ ├── test_perception.py # pytest └── test_integration.py # launch_testing ``` ## Debugging Toolkit ```bash # Topic inspection ros2 topic list ros2 topic info /camera/image_raw -v # Shows QoS details ros2 topic hz /camera/image_raw ros2 topic bw /camera/image_raw ros2 topic echo /joint_states --once # Node inspection ros2 node list ros2 node info /perception # Parameter management ros2 param list /perception ros2 param get /perception confidence_threshold ros2 param set /perception confidence_threshold 0.8 # Runtime change! # Lifecycle management ros2 lifecycle list /managed_perception ros2 lifecycle set /managed_perception configure ros2 lifecycle set /managed_perception activate # Service calls ros2 service list ros2 service call /get_pose my_interfaces/srv/GetPose "{}" # Action monitoring ros2 action list ros2 action info /pick_place ros2 action send_goal /pick_place my_interfaces/action/PickPlace "{target_pose: {x: 1.0}}" # Bag recording (ROS2 style) ros2 bag record -a # All topics ros2 bag record /camera/image /tf # Specific topics ros2 bag record -s mcap /camera/image # MCAP format (recommended) ros2 bag info recording/ # Inspect ros2 bag play recording/ --clock # Playback # DDS debugging ros2 doctor # System diagnostics ros2 daemon stop && ros2 daemon start # Reset discovery daemon ``` ## Production Deployment Checklist 1. **Use lifecycle nodes** for all critical components 2. **Set `ROS_LOCALHOST_ONLY=1`** if not communicating across machines 3. **Pin your DDS implementation** (CycloneDDS recommended) 4. **Configure QoS explicitly** — never rely on defaults for production 5. **Set `ROS_DOMAIN_ID`** to isolate your robot from others on the network 6. **Enable ROS2 security** (SROS2) for authenticated communication 7. **Use composition** for nodes that exchange large data 8. **Record bags in MCAP format** — better tooling, random access, compression 9. **Set up launch-testing** for integration tests 10. **Use `ros2 doctor`** as part of your health check pipeline