subprocess-util/src/p1st/repeat.py

import time
from pathlib import Path

from p1st.exec_print_capture import execute_print_capture
from p1st.unix_sock_input import wait_for_message


def repeat_until_successful(command: list[str],
                            socket_file: Path,
                            retries: int = 0,
                            retry_delay_seconds: float = 5) -> str:
    """
    Executes the given `command` and returns its stdout.

    If the command has failed, it is executed at most `retires` times again, until successful.
    Between each retry we wait for `retry_delay_seconds`.

    If no more retries are left, a UNIX socket is created at `socket_file`
    and we wait for user input.
    """
    while True:
        returncode: int
        stdout: str
        returncode, stdout, _stderr = execute_print_capture(command)

        # If no error occurred, return stdout of subprocess.
        if returncode == 0:
            return stdout
        # Else, an error has occurred.

        print(f'\n'
              f'Error while executing:\n'
              f'\t{command}\n'
              f'\tFor details, see above output.')

        # If retry attempts are left,
        # wait `retry_delay_seconds` and then execute the command again.
        if retries > 0:
            print(f'\tRetrying the failed command in {retry_delay_seconds} seconds.'
                  f'\n')
            time.sleep(retry_delay_seconds)
            retries -= 1
            continue
        # Else, no more retry attempts are left.

        # Print message and wait for user input.
        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()}"')
        wait_for_message(socket_file, [b'OK\n'])
        print()