# app.py
import os,socket,threading,sys

port=int(os.getenv("PORT","5678"))
print("echo tcp on",port,flush=True)

def handle(c,a):
    print("conn",a,flush=True)
    while (d:=c.recv(1024)):
        print("recv",d.decode(errors="ignore").strip(),flush=True)
        c.sendall(d)
    c.close()
    print("disc",a,flush=True)

s=socket.socket()
s.setsockopt(socket.SOL_SOCKET,socket.SO_REUSEADDR,1)
s.bind(("0.0.0.0",port))
s.listen()

while True:
    threading.Thread(target=handle,args=s.accept(),daemon=True).start()