# 查看当前使用的DDS实现
echo $RMW_IMPLEMENTATION
# 默认输出: rmw_fastrtps_cpp

# 切换到Cyclone DDS
export RMW_IMPLEMENTATION=rmw_cyclonedds_cpp

# minimal_node.py — 最简ROS2节点
import rclpy
from rclpy.node import Node

class MinimalNode(Node):
    def __init__(self):
        super().__init__('minimal_node')
        self.get_logger().info('ROS2节点已启动！')

def main():
    rclpy.init()
    node = MinimalNode()
    rclpy.spin(node)      # 阻塞等待回调
    node.destroy_node()
    rclpy.shutdown()

if __name__ == '__main__':
    main()

# 安装ROS2 (Ubuntu 24.04)
# 详见: https://docs.ros.org/en/jazzy/Installation.html
ros2 run my_package minimal_node

# 发布者示例
self.publisher = self.create_publisher(String, 'chatter', 10)
msg = String()
msg.data = 'Hello ROS2!'
self.publisher.publish(msg)

# 服务端示例
self.srv = self.create_service(AddTwoInts, 'add_two_ints', self.callback)

def callback(self, request, response):
    response.sum = request.a + request.b
    return response

# 动作反馈示例
goal_handle.publish_feedback(feedback_msg)    # 发布进度
goal_handle.succeed()                         # 标记完成
result = Fibonacci.Result()
result.sequence = feedback_msg.partial_sequence
return result

# 声明参数（带范围和描述）
from rcl_interfaces.msg import ParameterDescriptor, IntegerRange

descriptor = ParameterDescriptor(
    description='最大线速度(m/s)',
    integer_range=[IntegerRange(from_value=0, to_value=100, step=1)]
)
self.declare_parameter('max_speed', 50, descriptor)

from rclpy.qos import QoSProfile, ReliabilityPolicy, DurabilityPolicy, HistoryPolicy

# 场景1：传感器数据（允许丢帧，低延迟优先）
sensor_qos = QoSProfile(
    reliability=ReliabilityPolicy.BEST_EFFORT,
    durability=DurabilityPolicy.VOLATILE,
    history=HistoryPolicy.KEEP_LAST,
    depth=5
)

# 场景2：控制指令（不允许丢失）
control_qos = QoSProfile(
    reliability=ReliabilityPolicy.RELIABLE,
    durability=DurabilityPolicy.VOLATILE,
    history=HistoryPolicy.KEEP_LAST,
    depth=10
)

# 场景3：状态数据（晚加入也能获取最新状态）
status_qos = QoSProfile(
    reliability=ReliabilityPolicy.RELIABLE,
    durability=DurabilityPolicy.TRANSIENT_LOCAL,
    history=HistoryPolicy.KEEP_LAST,
    depth=1
)

ros2_ws/
├── src/                          # 源代码目录
│   ├── my_package/              # Python包
│   │   ├── my_package/          # 代码目录
│   │   │   ├── __init__.py
│   │   │   └── my_node.py
│   │   ├── launch/              # Launch文件
│   │   ├── config/              # 参数YAML
│   │   ├── package.xml          # 包清单
│   │   └── setup.py             # Python安装配置
│   └── my_interfaces/           # 自定义接口包
│       ├── msg/                 # 自定义消息
│       ├── srv/                 # 自定义服务
│       ├── action/              # 自定义动作
│       ├── CMakeLists.txt       # CMake构建
│       └── package.xml
├── build/                        # 编译中间产物
├── install/                      # 安装产物
└── log/                          # 日志

# 创建工作空间
mkdir -p ~/ros2_ws/src
cd ~/ros2_ws

# 创建Python包
ros2 pkg create --build-type ament_python my_package \
  --dependencies rclpy std_msgs

# 创建C++包
ros2 pkg create --build-type ament_cmake my_cpp_package \
  --dependencies rclcpp std_msgs

# 创建接口包（消息/服务/动作）
ros2 pkg create --build-type ament_cmake my_interfaces \
  --dependencies rosidl_default_generators

# 构建
colcon build --symlink-install
source install/setup.bash

# === 节点 ===
ros2 node list                    # 列出所有节点
ros2 node info /node_name         # 查看节点详情

# === 话题 ===
ros2 topic list                   # 列出所有话题
ros2 topic list -t                # 列出话题及类型
ros2 topic echo /topic_name       # 实时查看数据
ros2 topic info /topic_name       # 查看话题信息
ros2 topic hz /topic_name         # 查看发布频率
ros2 topic pub /topic std_msgs/msg/String "data: 'hello'"

# === 服务 ===
ros2 service list                 # 列出所有服务
ros2 service call /add_two_ints example_interfaces/srv/AddTwoInts "{a: 5, b: 3}"

# === 动作 ===
ros2 action list                  # 列出所有动作
ros2 action send_goal /fibonacci action_tutorials_interfaces/action/Fibonacci "{order: 10}"

# === 参数 ===
ros2 param list /node_name        # 列出节点的参数
ros2 param get /node_name param   # 获取参数值
ros2 param set /node_name param value  # 设置参数值

# === 数据记录 ===
ros2 bag record /topic1 /topic2   # 录制话题
ros2 bag play my_bag/             # 回放
ros2 bag info my_bag/             # 查看bag信息