con_futures.py

from concurrent.futures import ProcessPoolExecutor
from concurrent.futures.process import BrokenProcessPool
import time
import requests
import sys
import ctypes
import traceback
import signal
import psutil
import os
def handler(signum, frame):
    print("Forever is over!")
    raise TimeoutError("end of time")

def fn(n):
    print(f'return {n}*5')
    return n*5

def fn_timeout(n):
    print('sleeping 11 secs')
    time.sleep(11)
    print('fn_timeout finished running')
    return n*5

def fn_timeout_signal(n):
    signal.signal(signal.SIGALRM, handler)
    signal.alarm(5)
    print('sleeping 11 secs')
    time.sleep(11)
    print('fn_timeout finished running')
    signal.alarm(0)
    return n*5

def fn_exception(n):
    time.sleep(1)
    raise TypeError('just raise')
    return n*5

def fn_coredump(n):
    time.sleep(1)
    #https://codegolf.stackexchange.com/a/22383
    ctypes.string_at(1)
    return n*5

print('running..')
with ProcessPoolExecutor(max_workers=1) as executor:
    future = executor.submit(fn, 4)
    outputs = future.result(timeout=5)
print(f'output from future: {outputs}')

print('running timeout')
try:
    with ProcessPoolExecutor(max_workers=1) as executor:
        future = executor.submit(fn_timeout, 5)
        try:
            outputs = future.result(timeout=5)
        except TimeoutError as e:
            print(type(e), ''.join(traceback.format_tb(e.__traceback__)))
            print('this is timeout')
            # thanks to https://stackoverflow.com/questions/42782953/python-concurrent-futures-how-to-make-it-cancelable
            def kill_child_processes(parent_pid, sig=signal.SIGTERM):
                try:
                    parent = psutil.Process(parent_pid)
                except psutil.NoSuchProcess:
                    return
                children = parent.children(recursive=True)
                for process in children:
                    process.send_signal(sig)
            print('close and kill')
            executor.shutdown(wait=False)
            kill_child_processes(os.getpid())
except Exception as e:
    print(type(e), ''.join(traceback.format_tb(e.__traceback__)))
    print('should not be here')

print('running timeout signal')
try:
    with ProcessPoolExecutor(max_workers=1) as executor:
        future = executor.submit(fn_timeout_signal, 5)
        outputs = future.result() # fully trust installed signal to raise exception
except TimeoutError as e:
    print(type(e), ''.join(traceback.format_tb(e.__traceback__)))
    print('this is timeout with sigalarm')

print('running exception')
try:
    with ProcessPoolExecutor(max_workers=1) as executor:
         future = executor.submit(fn_exception, 6)
         outputs = future.result(timeout=5)
except Exception as e:
    print(type(e), ''.join(traceback.format_tb(e.__traceback__)))
    print('this is exception')

print('running crash')
try:
    with ProcessPoolExecutor(max_workers=1) as executor:
         future = executor.submit(fn_coredump, 7)
         outputs = future.result(timeout=5)
except BrokenProcessPool as e:
    print(type(e), ''.join(traceback.format_tb(e.__traceback__)))
    print('this is crash')