threading experiments in python 3.7

q1-process-till-done.py

from threading import Thread
from queue import Queue
import time

num_worker_threads = 1

print("start", time.strftime("%Y-%m-%d %H:%M:%S", time.gmtime()))

def task(item):
    print("IN", item)
    time.sleep(item)
    print("OUT", item)

def worker():
    while True:
        item = q.get()
        task(item)
        q.task_done()

q = Queue()
for i in range(num_worker_threads):
     t = Thread(target=worker)
     t.daemon = True
     t.start()

for item in range(4):
    q.put(item)

q.join()

print("done", time.strftime("%Y-%m-%d %H:%M:%S", time.gmtime()))

q2-long-running.py

import time
from concurrent import futures

def task(item):
    print("IN", item)
    time.sleep(item)
    print("OUT", item)

exec = futures.ThreadPoolExecutor(max_workers=2)

for item in range(4):
    exec.submit(task, item)
print("checkpoint 1")

for item in range(4):
    exec.submit(task, item)
print("checkpoint 2")

long running python tread with ThreadPoolExecutor, satisfying