pexpect's interact() reported "Inappropriate ioctl for device" when running on a VM with PowerCLI

Question

I have a simple script (child.py) as below:

#!/usr/bin/env python
import pexpect

def ency():
    child = pexpect.spawn("cryptsetup luksChangeKey /mnt/ency")
    child.expect('Enter passphrase to be changed:')
    child.sendline('password-old')
    child.expect('Enter .*: ')
    child.sendline('password-new')
    child.expect('Verify .*: ')
    child.sendline('password-new')
    child.interact()

ency()

I invoke this script using a different script (master.sh)

#!/bin/bash
python child.py 

The code run successfully when I run child.py, but when I envoke child.py using master.sh, I get the following error:

Traceback (most recent call last):
  File "child.py", line 15, in <module>
    ency()
  File "child.py", line 13, in ency
    child.interact()
  File "/usr/lib/python2.7/site-packages/pexpect-4.2.1-py2.7.egg/pexpect/pty_spawn.py", line 740, in interact
    mode = tty.tcgetattr(self.STDIN_FILENO)
termios.error: (25, 'Inappropriate ioctl for device')

Note that I am invoking master.sh using PowerCLI. I also tried to invoke child.py directly using PowerCLI's Invoke-vmscript –vm vmname –scripttext “python child.py” and still get the same behavior.

Any ideas or suggestions on how to resolve this?

Thanks

Answer 1

Since you are running the pexpect script on a VM I suppose you don't really need to interact with it. So just replace

child.interact()

with

child.expect(pexpect.EOF)  # also use the `timeout` argument if necessary

to wait for the child to complete.

---

According to the doc, interact()

gives control of the child process to the interactive user (the human at the keyboard). Keystrokes are sent to the child process, ...