Program continues to execute after exit

Question

After reading in an ip address from the user I want to exit out if not valid. It seems to continue executing the code in the function before exiting. I would like it to exit immediately. I have even tried using quit() and exit() in the expection but all had the same result.

Function:

def f_validate_args(test_args):
 try:
  socket.inet_aton(test_args.server)
 except socket.error as SE:
  raise SystemExit(SE)

 print 'Everything is OK!'

Main:

validation = f_validate_args(io_args)

print(io_args)

Running program with an Invalid IP:

Everything is OK
illegal IP address string passed to inet_aton

Running program with a Valid IP:

Everything is OK!
Namespace(...)

Answer 1

You can try os.system package, to kill from bash:

import os

def f_validate_args(test_args):
 try:
  socket.inet_aton(test_args.server)
 except socket.error as SE:
  os.system('pkill your_program_name')
  raise SystemExit(SE)

Answer 2

There may be resources (socket related) that prevent the program to exit cleanly.

Maybe dirty but sure to work: call os._exit . It calls low-level exit without using the exception mechanism that sys.exit uses.

def f_validate_args(test_args):
 try:
  socket.inet_aton(test_args.server)
 except socket.error as SE:
  print(str(SE))
  os._exit(1)

 print('Everything is OK!')

Of course, python doesn't have a chance to exit gracefully. Do this only if you can't do otherwise.

Answer 3

When an invalid IP is provided, the function will raise an OSError. So you will need to catch it with

def f_validate_args(test_args):
 try:
  socket.inet_aton(test_args.server)
 except OSError:
  # your error handling here
 except socket.error as SE:
  raise SystemExit(SE)

 print 'Everything is OK!'

Source: https://docs.python.org/3/library/socket.html#socket.inet_aton