test_async_approaches.py

test_async_approaches.py

from concurrent.futures import ThreadPoolExecutor, wait
from multiprocessing import cpu_count

import asyncio


def proc(arg):
    print(arg)


async def aproc(arg):
    print(arg)


def main(args):
    executor = ThreadPoolExecutor(max_workers=cpu_count())
    futures = [executor.submit(proc, i) for i in args]
    completed, pending = wait(futures)
    print("done main", len(completed), "/", len(pending))


async def amain(args):
    tasks = []

    for arg in args:
        tasks.append(asyncio.create_task(aproc(arg)))

    results = await asyncio.gather(*tasks)

    print("done async main", len(results))


if __name__ == "__main__":
    args = range(10)
    main(args)
    asyncio.run(amain(args))

• ThreadPoolExecutor
  • This allows to switch between thread pool, and process pool
  • Control number of parallel executions
  • Allows some control on blocking
  • does not color functions, a single thread is a single thread
• async/await
  • This allows to "nest" all the async colored functions, potentially more performant if multiple functions do IO
  • colored functions, can call sync code, but async functions can not be reused in sync contest
  • asyncio event loop does not rely on threading and is most performant even for smaller python tasks