'How to exit the entire application from a Python thread?

How can I exit my entire Python application from one of its threads? sys.exit() only terminates the thread in which it is called, so that is no help.

I would not like to use an os.kill() solution, as this isn't very clean.

pythonmultithreading


Solution 1:[1]

Short answer: use os._exit.

Long answer with example:

I yanked and slightly modified a simple threading example from a tutorial on DevShed:

import threading, sys, os

theVar = 1

class MyThread ( threading.Thread ):

   def run ( self ):

      global theVar
      print 'This is thread ' + str ( theVar ) + ' speaking.'
      print 'Hello and good bye.'
      theVar = theVar + 1
      if theVar == 4:
          #sys.exit(1)
          os._exit(1)
      print '(done)'

for x in xrange ( 7 ):
   MyThread().start()

If you keep sys.exit(1) commented out, the script will die after the third thread prints out. If you use sys.exit(1) and comment out os._exit(1), the third thread does not print (done), and the program runs through all seven threads.

os._exit "should normally only be used in the child process after a fork()" -- and a separate thread is close enough to that for your purpose. Also note that there are several enumerated values listed right after os._exit in that manual page, and you should prefer those as arguments to os._exit instead of simple numbers like I used in the example above.

Solution 2:[2]

Using thread.interrupt_main() may not help in some situation. KeyboardInterrupts are often used in command line applications to exit the current command or to clean the input line.

In addition, os._exit will kill the process immediately without running any finally blocks in your code, which may be dangerous (files and connections will not be closed for example).

The solution I've found is to register a signal handler in the main thread that raises a custom exception. Use the background thread to fire the signal.

import signal
import os
import threading
import time


class ExitCommand(Exception):
    pass


def signal_handler(signal, frame):
    raise ExitCommand()


def thread_job():
    time.sleep(5)
    os.kill(os.getpid(), signal.SIGUSR1)


signal.signal(signal.SIGUSR1, signal_handler)
threading.Thread(target=thread_job).start()  # thread will fire in 5 seconds
try:
    while True:
        user_input = raw_input('Blocked by raw_input loop ')
        # do something with 'user_input'
except ExitCommand:
    pass
finally:
    print('finally will still run')

Related questions:

Solution 3:[3]

The easiest way to exit the whole program is, we should terminate the program by using the process id (pid).

import os
import psutil

current_system_pid = os.getpid()

ThisSystem = psutil.Process(current_system_pid)
ThisSystem.terminate()

To install psutl:- "pip install psutil"

Solution 4:[4]

For Linux you can use the kill() command and pass the current process' ID and the SIGINT signal to start the end steps to exit the app.

os.kill(os.getpid(), signal.SIGINT)

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1 Mark Rushakoff
Solution 2
Solution 3 GR Tech School
Solution 4 Skatox

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