echo_server.py

import socket
import sys,traceback


def server(log_buffer=sys.stderr):
    # set an address for our server
    address = ('127.0.0.1', 10000)
    # TODO: Replace the following line with your code which will instantiate
    #       a TCP socket with IPv4 Addressing, call the socket you make 'sock'
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM, socket.IPPROTO_TCP)


    # TODO: You may find that if you repeatedly run the server script it fails,
    #       claiming that the port is already used.  You can set an option on
    #       your socket that will fix this problem. We DID NOT talk about this
    #       in class. Find the correct option by reading the very end of the
    #       socket library documentation:
    #       http://docs.python.org/3/library/socket.html#example
    sock.setsockopt(socket.SOL_SOCKET,socket.SO_REUSEADDR,1)
    sock.bind(address)
    sock.listen(1)

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

    # TODO: bind your new sock 'sock' to the address above and begin to listen
    #       for incoming connections

    try:
        # the outer loop controls the creation of new connection sockets. The
        # server will handle each incoming connection one at a time.
        while True:
            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:
                traceback.print_exc()

            finally:

                conn.close()
                print('echo complete, client connection closed', file=log_buffer)

    except KeyboardInterrupt:
        sock.close()


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