[Python] my python asyncio server won't stop even after all clients are disconnected

My asyncio server won't shut down if a client has connected even if the client closes the socket. Why won't it stop? If a client does not connect within 10 seconds it shuts down and the program closes.

My procedure:

• run server.py
• run client.py - client connects and immediately closes the socket.

Result:

• server hangs and won't close

I found that adding writer.close() in the clientHandler solved the issue but why? Where is this documented/explained?

# server
from os import path as ospath
import asyncio
import socket as Socket
import logger as log

logger = log.getLogger(fileName=ospath.join('log', 'server.log'), initialize=True)

class Client():
def __init__(self, socket:Socket=None, addr:tuple=None) -> None:
self.socket = socket
self.addr = addr
self.connected = False

class App():
def __init__(self) -> None:
self.quit = False
self.clients = []

async def clientHandler(reader, writer):
logger.info('client handler starting')

async def main():
logger.info("server app starting")
app = App()

# start socket server
ipaddr = Socket.gethostbyname(Socket.gethostname())
port = 32843
logger.info(f'starting socket server ({ipaddr}:{port})')
server = await asyncio.start_server(clientHandler, ipaddr, port=32843)

logger.info('waiting for client to connect...')
await asyncio.sleep(10)
logger.info('closing server')
server.close()

await server.wait_closed()
logger.info('server closed')

if __name__ == '__main__':
asyncio.run(main())


# client
import socket

dest_ip = socket.gethostbyname(socket.gethostname())
dest_port = 32843
encoder = "utf-8"

client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client_socket.connect((dest_ip, dest_port))

client_socket.shutdown(socket.SHUT_RDWR)
client_socket.close()

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