service通信client-python

service通信client

service通信分为server和client端

实现

1. 创建package(如果创建过可省略)

ros2 pkg create --build-type ament_python py_srvcli --dependencies rclpy example_interfaces

可以修改package.xml文件如下信息

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

2. 编写client节点代码

2.1 编写代码

1. 在package的py_srvcli下创建client.py文件,代码如下

import rclpy
from rclpy.node import Node
from example_interfaces.srv import AddTwoInts
import time

class MyNode(Node):
    def __init__(self):
        super(MyNode, self).__init__('py_client')
        self.cli = self.create_client(AddTwoInts,'py_service')
        while not self.cli.wait_for_service(timeout_sec=1.0):
            self.get_logger().info('service not available,waiting again...')
        self.req = AddTwoInts.Request()
        time.sleep(3)
        self.send_request(10,20)

    def send_request(self,a,b):
        self.req.a = int(a)
        self.req.b = int(b)
        self.future = self.cli.call_async(self.req)
        self.future.add_done_callback(self.call_back)

    def call_back(self,future):
        self.get_logger().info(f'receive response {future.result().sum}')


def main():
    rclpy.init()
    node = MyNode()
    rclpy.spin(node)
    node.destroy_node()
    rclpy.shutdown()

if __name__ == '__main__':
    main()

2.2 添加配置

1. 打开setup.py文件,在console_scripts节点下添加配置

'client = py_srvcli.client:main',

3. 编译工程

colcon build

4. 运行节点

ros2 run py_srvcli client