asyncio 使用记录_python asyncio async ensure声明的函数能有返回值吗?

 
import asyncio
import time
import requests
from concurrent.futures import ALL_COMPLETED,FIRST_COMPLETED,FIRST_EXCEPTION
 
async def task2():
    print('task2')
    # res = requests.get('https://www.baidu.com',verify=False)
    # print(res.status_code)
    await asyncio.sleep(3)
    # print('sleep 3 task2')
    return 111
async def task(num):
    print('task')
    t = loop.create_task(task2())
    await asyncio.sleep(num)
    await t
    print('sleep 2 task')
    if num == 2:
        raise NotImplemented
 
    return f'task res {num}'
 
async def main(loop):
    # 正确的写法1
    task1 = [loop.create_task(task(1)) for _ in range(1100)] # 3.7 可用 asysico.create_task()
    task22 = loop.create_task(task2())
    for t in task1:
        await t
    await task22
    # 写法2
    # res1 = asyncio.gather(task(1))
    # res2 = asyncio.gather(task(1))
    # res3 = asyncio.wait([task(1),task(3)],return_when=FIRST_COMPLETED)
    # res3 = asyncio.wait([task(1) for i in range(100)],return_when=ALL_COMPLETED) # wait方式如果不一次写全 会导致异步失败
    # res4 = asyncio.wait([task(1) for i in range(100)],return_when=ALL_COMPLETED)
    # # await res1
    # # await res2
    # pending,done = await res3
    # print(pending,done,"*"*11)
    # res = await asyncio.gather(task(1))
    # res = await asyncio.gather(task(1))
    # print(res)
    # t1 = [asyncio.ensure_future(task(5)) for _ in range(20) ]
    # t2 = asyncio.ensure_future(task2())
    # for t in t1:
    #     res = await t
    #     print(f'res = {res}')
    # await t2
 
 
    # 错误的写法1  假异步
    # await loop.create_task(task())
    # await loop.create_task(task2())
    # 错误的写法2  假异步
    # await asyncio.ensure_future(task2())
    # await asyncio.ensure_future(task2())
 
 
 
if __name__ == '__main__':
    # 创建任务的方法
    # 1. asyncio.gather  全称黑盒  只告诉结果
    # 2. asyncio.wait     状态+结果  有参数 选择返回的时机 done,pending = awit res
    # 3. loop.create_task
    # 4. asyncio.ensure_future 无返回值
    # 5. asyncio.create_task  # 3.7
    # 6. asyncio.shield  # 确保任务完成 即使cancel 也会被执行得到结果
 
    start = time.perf_counter()
    loop = asyncio.get_event_loop()
    # method 1
    # tasks =asyncio.gather(*[task(_) for _ in range(1000)],return_exceptions=True) # 方式一  gather
    # loop.run_until_complete(tasks)
    # print(tasks.result())
    # # end 1
 
    # method 2
 
    # tasks = loop.create_task(task())
    # loop.run_until_complete(tasks)
 
    # method 3 asyncio.wait
    tasks = asyncio.wait([task2() for _ in range(1000)])
    done,pending =  loop.run_until_complete(tasks)
    print(done)
 
    # method 4 main 中 创建
    # loop.run_until_complete(loop.create_task(main(loop)))
    # loop.run_forever()
    loop.time()
    print(f'耗时{time.perf_counter()-start}s')
'
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