Demonstrating issues between sys.exit and os._exit when active threads are running.

1_sys_exit.py

import logging
import os
import sys
import threading
import time

import six


logging.basicConfig(level=logging.INFO, format='%(name)s %(threadName)s %(thread)d [%(levelname)s]: %(message)s')


def bad_func(shared_state):
    time.sleep(1)
    try:
        raise Exception('This is a stupid')
    except:
        shared_state['exc_info'] = sys.exc_info()


def good_func():
    while True:
        time.sleep(1)
        logging.info('All good!')


logging.info('Python Version: %s', sys.version)
logging.info('PID: %s', os.getpid())
bad_state = {}
bad_thread = threading.Thread(target=bad_func, name='bad_thread', args=(bad_state,))
logging.info('bad_thread daemon: %r', bad_thread.daemon)
good_thread = threading.Thread(target=good_func, name='good_thread')
logging.info('good_thread daemon: %r', bad_thread.daemon)
good_thread.start()
bad_thread.start()
logging.info('Thread count: %d', threading.active_count())
try:
    while True:
        exc_info = bad_state.get('exc_info')
        if exc_info:
            six.reraise(*exc_info)
        good_thread.join(0.1)
        bad_thread.join(0.1)
except Exception as e:
    logging.error('Caught an exception, exiting: %r', e)
    sys.exit(2)

logging.info('Done from main.')

1_sys_exit.py.txt

root MainThread 140736469173184 [INFO]: Python Version: 2.7.11 (default, Jul 19 2016, 10:14:23)
[GCC 4.2.1 Compatible Apple LLVM 7.0.2 (clang-700.1.81)]
root MainThread 140736469173184 [INFO]: PID: 30663
root MainThread 140736469173184 [INFO]: bad_thread daemon: False
root MainThread 140736469173184 [INFO]: good_thread daemon: False
root MainThread 140736469173184 [INFO]: Thread count: 3
root good_thread 123145383870464 [INFO]: All good!
root MainThread 140736469173184 [ERROR]: Caught an exception, exiting: Exception('This is a stupid',)
root good_thread 123145383870464 [INFO]: All good!
root good_thread 123145383870464 [INFO]: All good!
root good_thread 123145383870464 [INFO]: All good!
root good_thread 123145383870464 [INFO]: All good!
root good_thread 123145383870464 [INFO]: All good!
root good_thread 123145383870464 [INFO]: All good!
root good_thread 123145383870464 [INFO]: All good!
root good_thread 123145383870464 [INFO]: All good!
root good_thread 123145383870464 [INFO]: All good!
...

3_os_exit.py

import logging
import os
import sys
import threading
import time

import six


logging.basicConfig(level=logging.INFO, format='%(name)s %(threadName)s %(thread)d [%(levelname)s]: %(message)s')


def bad_func(shared_state):
    time.sleep(1)
    try:
        raise Exception('This is a stupid')
    except:
        shared_state['exc_info'] = sys.exc_info()


def good_func():
    while True:
        time.sleep(1)
        logging.info('All good!')


logging.info('Python Version: %s', sys.version)
logging.info('PID: %s', os.getpid())
bad_state = {}
bad_thread = threading.Thread(target=bad_func, name='bad_thread', args=(bad_state,))
logging.info('bad_thread daemon: %r', bad_thread.daemon)
good_thread = threading.Thread(target=good_func, name='good_thread')
logging.info('good_thread daemon: %r', bad_thread.daemon)
good_thread.start()
bad_thread.start()
logging.info('Thread count: %d', threading.active_count())
try:
    while True:
        exc_info = bad_state.get('exc_info')
        if exc_info:
            six.reraise(*exc_info)
        good_thread.join(0.1)
        bad_thread.join(0.1)
except Exception as e:
    logging.error('Caught an exception, exiting: %r', e)
    exit_func = os._exit if threading.active_count() > 1 else sys.exit()
    exit_func(2)

logging.info('Done from main.')

4_os_exit.py.txt

root MainThread 140736469173184 [INFO]: Python Version: 2.7.11 (default, Jul 19 2016, 10:14:23)
[GCC 4.2.1 Compatible Apple LLVM 7.0.2 (clang-700.1.81)]
root MainThread 140736469173184 [INFO]: PID: 30554
root MainThread 140736469173184 [INFO]: bad_thread daemon: False
root MainThread 140736469173184 [INFO]: good_thread daemon: False
root MainThread 140736469173184 [INFO]: Thread count: 3
root good_thread 123145366458368 [INFO]: All good!
root MainThread 140736469173184 [ERROR]: Caught an exception, exiting: Exception('This is a stupid',)