Im quite new to ROS2 humble, so any advice would be appreciated. I am trying to build a socket inside the ROS2 node, so that I can receive some commands from other user. However, I get some build error when I try to build the package. The build error is mainly about:

AttributeError: module 'socket' has no attribute '_GLOBAL_DEFAULT_TIMEOUT'

The code I'm trying to execute is the following:

#!/usr/bin/env python3
# coding=utf-8

import socket
import rclpy
from std_msgs.msg import Char
from std_msgs.msg import Float64

class MySocket:
    def __init__(self, sock=None):
        if sock is None:
            self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            self.sock = sock
        self.host = ""
        self.port = 8
        self.MSGLEN = 1024

    def connect(self):
        self.sock.connect((self.host, self.port))

    def mysend(self, msg):
        if len(msg) != 1:
            raise ValueError("Accepting only the valid commands")
        totalsent = 0
        while totalsent < 1:  
            sent = self.sock.send(msg.encode())  
            if sent == 0:
                raise RuntimeError("Socket connection broken")
            totalsent += sent

    def distSend(self, msg):
        if not isinstance(msg, (int, float)):
            raise ValueError("Accepting only valid numeric values")
        msg_str = str(msg)
        totalsent = 0
        while totalsent < len(msg_str):
            sent = self.sock.send(msg_str[totalsent:].encode())
            if sent == 0:
                raise RuntimeError("Socket connection broken")
            totalsent += sent

    def myreceive(self):
        received_char = self.sock.recv(1).decode()
        if not received_char:
            raise RuntimeError("Socket connection broken")
        return received_char

global toMaster # command
global toMasterDist # current distance from the wall

def callback(msg: Char):
    global toMaster
    toMaster = msg.data

def dist_callback(msg: Float64):
    global toMasterDist
    toMasterDist = msg.data

def main():
    node = rclpy.create_node('socket')
    pub = node.create_publisher(Char, 'from_master', 10)
    sub = node.create_subscription(Char, 'to_master', callback, 10)
    dist_sub = node.create_subscription(Float64, 'to_master_dist', dist_callback, 10)
    s = MySocket()
    fm = Char()
    while 1:
        cmd = s.myreceive()
        if cmd == 'M':
            fm.data = 109
            while toMaster != 'A':
            if toMaster == 'A':
                toMaster = '0'
        elif cmd == 'D':
            fm.data = 100
            while toMaster != 'A':
            if toMaster == 'A':
                toMaster = '0'
        elif cmd == 'F':
            fm.data = 102
            while toMaster != 'A':
            if toMaster == 'A':
                toMaster = '0'


Are there drivers for TCP/IP to communicate with external environment outside of ROS2? Thanks in advance

  • $\begingroup$ Suggest you post the whole output so we can see what leads up that error. $\endgroup$
    – billy
    Nov 21 at 8:23


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