# List all nodes
ros2 node list

# Node info
ros2 node info /ball_detector

# Output:
#   Subscribers:
#     /camera/image_raw: sensor_msgs/msg/Image
#   Publishers:
#     /ball_position: geometry_msgs/msg/Point

# List all topics
ros2 topic list

# Topic info
ros2 topic info /ball_position

# Echo topic (see messages)
ros2 topic echo /ball_position

# Echo with rate limit
ros2 topic echo /ball_position --once

# Publish test message
ros2 topic pub /cmd_vel geometry_msgs/msg/Twist \
  "{linear: {x: 0.1}, angular: {z: 0.0}}"

# Check publishing rate
ros2 topic hz /camera/image_raw

# List services
ros2 service list

# Service type
ros2 service type /reset_simulation

# Call service
ros2 service call /reset_simulation std_srvs/srv/Empty

# List parameters
ros2 param list /ball_detector

# Get parameter
ros2 param get /ball_detector camera_height

# Set parameter
ros2 param set /ball_detector camera_height 0.5

# Launch RQT
rqt

# Useful plugins:
# - Node Graph (visualize nodes & topics)
# - Image View (see camera feed)
# - Plot (graph numeric values)
# - Console (see log messages)

# Launch RViz
rviz2

# Add displays:
# - TF (coordinate frames)
# - Image (camera)
# - Marker (custom visualization)
# - PointCloud2 (3D points)

# View camera feed
ros2 run rqt_image_view rqt_image_view

# Select topic: /camera/image_raw or /debug_image

# Log messages
self.get_logger().debug('Detailed info')
self.get_logger().info('Normal info')
self.get_logger().warn('Warning!')
self.get_logger().error('Error occurred')
self.get_logger().fatal('Critical failure')

RCLCPP_DEBUG(this->get_logger(), "Detailed info");
RCLCPP_INFO(this->get_logger(), "Normal info");
RCLCPP_WARN(this->get_logger(), "Warning!");
RCLCPP_ERROR(this->get_logger(), "Error occurred");
RCLCPP_FATAL(this->get_logger(), "Critical failure");

# At runtime
ros2 run <package> <node> --ros-args --log-level debug

# Specific logger
ros2 run <package> <node> --ros-args \
  --log-level my_node:=debug

# Check if package built
ros2 pkg list | grep <package>

# Check executable exists
ros2 run <package> <node> --help

# Check dependencies
rosdep install --from-paths src --ignore-src -r -y

# Check QoS compatibility
ros2 topic info /topic_name -v

# Common QoS issues:
# - Publisher/subscriber have different reliability
# - Different durability settings

# View TF tree
ros2 run tf2_tools view_frames

# Look up specific transform
ros2 run tf2_ros tf2_echo odom base_link

# Common errors:
# - "Could not find a connection" → missing TF publisher
# - "Lookup would require extrapolation" → time sync issue

# Check if camera detected
ls /dev/video*

# Check camera info
v4l2-ctl --list-devices

# Adjust camera settings
v4l2-ctl -d /dev/video0 --list-ctrls
v4l2-ctl -d /dev/video0 --set-ctrl=exposure_auto=1

# Quick print
print(f"ball_position: {x}, {y}")

# With type info
print(f"image type: {type(image)}, shape: {image.shape}")

import pdb

def my_function():
    x = calculate_something()
    pdb.set_trace()  # Breakpoint here
    return x

import cv2

# Save intermediate images
cv2.imwrite('/tmp/debug_mask.png', mask)
cv2.imwrite('/tmp/debug_edges.png', edges)

# Show in window (if display available)
cv2.imshow('Debug', image)
cv2.waitKey(1)

# Build with debug symbols
colcon build --cmake-args -DCMAKE_BUILD_TYPE=Debug

# Run with GDB
gdb --args ros2 run <package> <node>

# GDB commands:
# run          - start program
# break <line> - set breakpoint
# next         - next line
# step         - step into function
# print <var>  - print variable
# backtrace    - show call stack

# In CMakeLists.txt
add_compile_options(-fsanitize=address)
add_link_options(-fsanitize=address)

# Check node CPU usage
top
htop

# ROS 2 specific
ros2 topic hz /camera/image_raw  # Check rate
ros2 topic delay /camera/image_raw  # Check latency

import time

start = time.time()
# ... code to measure ...
elapsed = time.time() - start
self.get_logger().info(f'Processing took {elapsed*1000:.1f} ms')

import cProfile

cProfile.run('my_function()')

# Verbose output
webots --stdout --stderr world.wbt

# Log file
webots --log-file=webots.log world.wbt

# Reset via service
ros2 service call /supervisor/reset_simulation std_srvs/srv/Empty

# Record topics
ros2 bag record /camera/image_raw /imu/data

# Record all topics
ros2 bag record -a

# Playback
ros2 bag play rosbag2_*/

# Info
ros2 bag info rosbag2_*/