keepalive_demo.py

import argparse
import socket

parser = argparse.ArgumentParser(description="keepalive example")
parser.add_argument("mode", choices=("server", "client"))


def server():
    listener = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    listener.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    listener.bind(('localhost', 9999))
    listener.listen(1)
    client, _ = listener.accept()
    client.recv(1024)


def client():
    client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    # Activate TCP keep alive.
    client.setsockopt(socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1)
    # Wait one minute before sending a keep alive segment.
    client.setsockopt(socket.IPPROTO_TCP, socket.TCP_KEEPIDLE, 60)
    client.connect(('localhost', 9999))
    client.recv(1024)


{"client": client, "server": server}[parser.parse_args().mode]()