1. 自定义srv消息

1.1 创建package(创建过可省略)

  1. ros2 pkg create --build-type ament_cmake msg_srv

可以修改package.xml文件如下信息

  1. <description>C++ client server tutorial</description>
  2. <maintainer email="you@email.com">Your Name</maintainer>
  3. <license>Apache License 2.0</license>

1.2 在工程下创建srv文件夹,创建AddThreeInts.srv并填写如下内容

  1. int64 a
  2. int64 b
  3. int64 c
  4. ---
  5. int64 sum

1.3 配置cmake

  1. find_package(rosidl_default_generators REQUIRED)
  3. rosidl_generate_interfaces(${PROJECT_NAME}
  4.   ...
  5.   "srv/AddThreeInts.srv"
  6. )

1.4 配置package.xml文件

  1. <build_depend>rosidl_default_generators</build_depend>
  3. <exec_depend>rosidl_default_runtime</exec_depend>
  5. <member_of_group>rosidl_interface_packages</member_of_group>

1.5 编译工程

  1. colcon build --packages-select msg_srv

1.6 显示消息详情

  1. ros2 interface show msg_srv/srv/AddThreeInts

2. 使用自定义的srv消息

client

  1. import rclpy
  2. from rclpy.node import Node
  3. from msg_srv.srv import AddThreeInts
  5. class MyNode(Node):
  6.     def __init__(self):
  7.         super(MyNode, self).__init__('client_py')
  8.         self.cli = self.create_client(AddThreeInts,'py_service')
  9.         while not self.cli.wait_for_service(timeout_sec=1.0):
  10.             self.get_logger().info('service not available,waiting again...')
  11.         self.req = AddThreeInts.Request()
  13.     def send_request(self,a,b,c):
  14.         self.req.a = int(a)
  15.         self.req.b = int(b)
  16.         self.req.c = int(c)
  17.         self.future = self.cli.call_async(self.req)
  19. def main():
  20.     rclpy.init()
  21.     node = MyNode()
  23.     # send request
  24.     node.send_request(10,20,30)
  25.     while rclpy.ok():
  26.         rclpy.spin_once(node)
  27.         if node.future.done():
  28.             try:
  29.                 response = node.future.result()
  30.             except Exception as e:
  31.                 node.get_logger().info(f'servie error:{e}')
  32.             else:
  33.                 node.get_logger().info(f'result:{response.sum}')
  34.                 break
  36.     node.destroy_node()
  37.     rclpy.shutdown()
  39. if __name__ == '__main__':
  40.     main()

server

  1. from msg_srv.srv import AddThreeInts
  2. import rclpy
  3. from rclpy.node import Node
  6. class MyServer(Node):
  7.     def __init__(self):
  8.         super(MyServer, self).__init__('py_server')
  9.         self.service = self.create_service(AddThreeInts, 'py_service', self.call_back)
  11.     def call_back(self, req, res):
  12.         res.sum = req.a + req.b + req.c
  13.         return res
  16. def main():
  17.     rclpy.init()
  18.     node = MyServer()
  19.     rclpy.spin(node)
  20.     rclpy.shutdown()
  23. if __name__ == '__main__':
  24.     main()

package.xml配置

  1. <depend>msg_srv</depend>

setup.py配置

  1. entry_points={
  2.     'console_scripts': [
  3.         ...
  4.         'client_srv = py_srvcli.client_srv:main',
  5.         'server_srv = py_srvcli.server_srv:main',
  6.     ],
  7. },

编译工程

  1. colcon build

运行节点

  1. ros2 run py_srvcli client_srv 
  2. ros2 run py_srvcli server_srv