import asyncio
import random
import time


async def worker(name, queue):
    while True:
        #get a work item out of the queue.
        sleep_for = await queu.get()

        #sleep for the 'sleep for' seconds.
        await asyncio.sleep(sleep_for)

        #notify the queue that the work item has been processed.
        queue.task_done()

        print(f'{name} has slept for {sleep_for:.2f} seconds')




async def main():
    #create a queue that we will use to store our workload
    queue = asyncio.Queue()
    
    #generate random timings and put them into the queue
    total_sleep_time = 0
    for _ in range(2):
        sleep_for = random.uniform(0.05, 1.0)
        total_sleep_time += sleep_for
        queue.put_nowait(sleep_for)

    #create three worker tasks to process teh queue concurrently
    tasks = []
    for i in range(3):
        task = asyncio.create_task(worker(f'worker-{i}', queue))
        tasks.append(task)

    started_at = time.monotonic()
    await queue.join()

    total_sleep_time = time.monotonic() - started_at

    #cancel our worker tasks
    for task in tasks:
        task.cancel()

    #wait until all worker tasks are cancelled.
    await asyncio.gather(*tasks, return_exceptions=True)

    print('===')
    print(f'3 workers slept in parallel for {total_slept_for:.2f} seconds')
    print(f'total expected sleep time: {total_sleep_time:.2f} seconds')

asyncio.run(main())