multiproc.py

import time
import queue
import sys
import ctypes
import multiprocessing as mp
import traceback

def fn(n, out_q):
    print(f'return {n}*5')
    result = n*5
    out_q.put(result)

def fn_timeout(n, out_q):
    print('sleeping 11 secs')
    time.sleep(11)
    result = n*5
    out_q.put(result)

def fn_exception(n, out_q):
    try:
        time.sleep(1)
        raise TypeError('just raise')
        result = n*5
        out_q.put(result)
    except Exception as e:
        out_q.put(e)

def fn_coredump(n, out_q):
    time.sleep(1)
    #https://codegolf.stackexchange.com/a/22383
    ctypes.string_at(1)
    result = n*5
    out_q.put(result)


print('running..')
try:
    outqueue = mp.Queue(maxsize=1)
    p = mp.Process(target=fn, args=(5, outqueue))
    p.start()
    p.join(timeout=5)
    result = outqueue.get()
    print(f'result = {result}')

except Exception as e:
    print(f'exception {type(e)}')

print('running timeout')
try:
    outqueue = mp.Queue(maxsize=1)
    p = mp.Process(target=fn_timeout, args=(6, outqueue))
    p.start()
    p.join(timeout=5)
    result = outqueue.get(timeout=0)
    print(f'result = {result}')
except queue.Empty as e:
    print(type(e), ''.join(traceback.format_tb(e.__traceback__)))
    p.terminate()
    print('this is timeout')

print('running exception')
try:
    outqueue = mp.Queue(maxsize=1)
    p = mp.Process(target=fn_exception, args=(6, outqueue))
    p.start()
    p.join(timeout=5)
    result = outqueue.get(timeout=0)
    if type(result) != int:
        raise result
    else:
        print(f'result = {result}')
except Exception as e:
    print(type(e), ''.join(traceback.format_tb(e.__traceback__)))
    print('this is exception')

print('running coredump')
try:
    outqueue = mp.Queue(maxsize=1)
    p = mp.Process(target=fn_coredump, args=(6, outqueue))
    p.start()
    p.join(timeout=5)
    result = outqueue.get(timeout=0)
    print(f'result = {result}')
except queue.Empty as e:
    if not p.is_alive() and p.exitcode < 0: # sigsegv is -11
        print(f'exitcode: {p.exitcode}')
        print(type(e), ''.join(traceback.format_tb(e.__traceback__)))
        print('this is coredump')
    else:
        print('timeout but still alive and has unexpected exitcode. unexpected')

except Exception as e:
    print(type(e), ''.join(traceback.format_tb(e.__traceback__)))
    print('unexpect')