echo_server.py

import socket
import sys
import traceback


def server(log_buffer=sys.stderr):
    # set an address for our server
    address = ('127.0.0.1', 10000)

    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM, socket.IPPROTO_TCP)
    sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)

    # log that we are building a server
    print("making a server on {0}:{1}".format(*address), file=log_buffer)

    sock.bind(address)
    sock.listen(1)
    sock.settimeout(5)

    while True:
        # the outer loop controls the creation of new connection sockets. The
        # server will handle each incoming connection one at a time.
        try:
            print('waiting for a connection', file=log_buffer)

            conn, addr = sock.accept()
            try:
                print('connection - {0}:{1}'.format(*addr), file=log_buffer)

                while True:
                    data = conn.recv(16)
                    print('received "{0}"'.format(data.decode('utf8')))

                    conn.sendall(data)
                    print('sent "{0}"'.format(data.decode('utf8')))

                    if len(data) < 16:
                        break
            except Exception as e:
                traceback.print_exc()
                sys.exit(1)

            finally:
                conn.close()
                print(
                    'echo complete, client connection closed', file=log_buffer
                )
        except socket.timeout:
            continue

        except KeyboardInterrupt:
            print('quitting echo server', file=log_buffer)
            sock.close()


if __name__ == '__main__':
    server()
    sys.exit(0)