使用python結合redis 開發ros2節點

目的

在ros2中，使用redis作爲實時數據共享，減少各個節點中的數據交互，從而減少系統開銷。

功能

1、每一秒發佈一次topic
2、每一秒寫一次數據庫，並調用

環境準備

1、已經安裝有ros2的ubuntu虛擬機
2、安裝python開發環境
3、redis已經安裝完成，如果沒有完成請參照：內存數據庫redis，pyhon操作-環境準備和簡單示例

程序示例

import rclpy
import os
from rclpy.node import Node
from std_msgs.msg import String
import pathlib
from redis import ConnectionPool
import redis
class robot_start(Node):
     def __init__(self):
        super().__init__('talker',namespace='test')
        self.i = 0
        self.pub = self.create_publisher(String, 'chatter')
        self.timer = self.create_timer(1.0, self.timer_callback)
        self.redis_conn = redis.Redis(host='localhost', port=6379, decode_responses=True)   
        self.redis_conn.set('name', 'aaa')
        self.count =1

    def timer_callback(self):
        msg = String()
        msg.data = 'Hello World: {0}'.format(self.i)
        self.i += 1
        self.get_logger().info('Publishing: "{0}"'.format(msg.data))
        self.pub.publish(msg)
        
        self.count += 1
        self.redis_conn.set('name', self.count)
        self.get_logger().info(self.redis_conn['name'])
        self.get_logger().info(self.redis_conn.get('name'))  

def main(args=None):
    rclpy.init(args=args)

    robotstart = robot_start()

    rclpy.spin(robotstart)
    
    robotstart.destroy_node()
    rclpy.shutdown()
 

if __name__ == '__main__':
    # Runs a talker node when this script is run directly (not through an entrypoint)
    main()

結果

[INFO] [test.talker]: Publishing: "Hello World: 0"
[INFO] [test.talker]: 2
[INFO] [test.talker]: 2
[INFO] [test.talker]: Publishing: "Hello World: 1"
[INFO] [test.talker]: 3
[INFO] [test.talker]: 3
[INFO] [test.talker]: Publishing: "Hello World: 2"
[INFO] [test.talker]: 4
[INFO] [test.talker]: 4
[INFO] [test.talker]: Publishing: "Hello World: 3"
[INFO] [test.talker]: 5
[INFO] [test.talker]: 5
[INFO] [test.talker]: Publishing: "Hello World: 4"
[INFO] [test.talker]: 6
[INFO] [test.talker]: 6
[INFO] [test.talker]: Publishing: "Hello World: 5"
[INFO] [test.talker]: 7
[INFO] [test.talker]: 7