login_and_source_config.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import pexpect
import signal
import fcntl
import termios
import struct


def login_and_source_config(command_spawn, config_file):
    c = pexpect.spawn(command_spawn, timeout=3)

    prompt = ['.*$']
    try:
        c.expect(prompt)

        with open(config_file) as f:
            config = f.read()

            c.sendline('CONFIG_FILE=$(mktemp)')
            c.expect(prompt)
            c.sendline("""cat << EOF > $TMP_CONFIG_FILE
{config}
EOF
""".format(config=config))
            c.expect(prompt)
            c.sendline('source $TMP_CONFIG_FILE')
            c.expect(prompt)

        def sigwinch_passthrough(sig, data):
            # @see https://github.com/pexpect/pexpect/blob/master/examples/script.py
            # Check for buggy platforms (see pexpect.setwinsize()).
            if 'TIOCGWINSZ' in dir(termios):
                TIOCGWINSZ = termios.TIOCGWINSZ
            else:
                TIOCGWINSZ = 1074295912 # assume
            s = struct.pack("HHHH", 0, 0, 0, 0)
            a = struct.unpack('HHHH', fcntl.ioctl(sys.stdout.fileno(), TIOCGWINSZ, s))
            c.setwinsize(a[0], a[1])

        signal.signal(signal.SIGWINCH, sigwinch_passthrough)
        c.interact()

    except pexpect.TIMEOUT:
        return


if __name__ == '__main__':
    import sys

    config_file_for_source = sys.argv[1]
    login_command = " ".join(sys.argv[2:])

    login_and_source_config(login_command, config_file_for_source)