subprocess-util/rsync_inform.py

import socket
from pathlib import Path

from exec_print_capture import execute_print_capture


def rsync_inform(rsync_cmd: list[str],
                 inform_cmd: list[str],
                 user_input_file: Path):
    """
    First, this method transfers files to a remote pc.

    Then, it informs the remote pc.

    If some error occurs during the above steps,
    it waits for user input (via a UNIX-socket) and repeats the failed step.

    :param rsync_cmd:
    :param inform_cmd:
    :param user_input_file:
    :return:
    """

    # - rsync to remote pc
    #   - catch error
    #   - wait until user input, then repeat
    _execute_loop_until_successful(rsync_cmd, user_input_file)

    #   - inform remote pc about complete rsync
    #     - catch error
    #     - wait until user input, then repeat
    _execute_loop_until_successful(inform_cmd, user_input_file)


def _execute_loop_until_successful(cmd: list[str], user_input_file: Path):
    while True:
        returncode, _out, _err = execute_print_capture(cmd)
        if returncode == 0:
            break
        else:
            print(f'\n'
                  f'Error while executing:\n'
                  f'\t{cmd}\n'
                  f'\tFor details, see above output.')
            _wait_for_user(user_input_file)
            print()


def _wait_for_user(socket_file: Path):
    """
    Waits until user writes 'OK\n' to UNIX-socket.
    """

    # INSPIRATION: https://pymotw.com/3/socket/uds.html

    print(f'Info:\n'
          f'\tPlease fix the above error first. Then continue here:\n'
          f'\tsudo pacman -S --needed openbsd-netcat\n'
          f'\techo "OK" | nc -U "{socket_file.absolute()}"')

    sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
    sock.bind(str(socket_file))
    sock.listen(1)

    while True:
        connection, client_address = sock.accept()
        try:
            b: bytes = connection.recv(32)
            if b == b'OK\n':
                print('Received "OK" from user.')
                break
            else:
                print(f'Received unknown message: {b}')
        except Exception as e:
            print(f'Error while reading message: {e}')
        finally:
            connection.close()

    sock.close()
    socket_file.unlink(missing_ok=False)