example5.py

# ch10/example5.py

from concurrent.futures import ThreadPoolExecutor
import asyncio
import time

def count_down(name, delay):
    indents = (ord(name) - ord('A')) * '\t'

    n = 3
    while n:
        time.sleep(delay)

        duration = time.perf_counter() - start
        print('-' * 40)
        print('%.4f \t%s%s = %i' % (duration, indents, name, n))

        n -= 1

async def main():
    futures = [loop.run_in_executor(
        executor,
        count_down,
        *args
    ) for args in [('A', 1), ('B', 0.8), ('C', 0.5)]]

    await asyncio.gather(*futures)

    print('-' * 40)
    print('Done.')

start = time.perf_counter()
executor = ThreadPoolExecutor(max_workers=3)
loop = asyncio.get_event_loop()
loop.run_until_complete(main())