我需要定期调用任务,但是(a)等待时间几乎超过了周期。
在下面的代码中,如何运行do_somthing()任务而无需等待结果?
import asyncio
import time
from random import randint
period = 1 # Second
def get_epoch_ms():
return int(time.time() * 1000.0)
async def do_somthing(name):
print("Start :", name, get_epoch_ms())
try:
# Do something which may takes more than 1 secs.
slp = randint(1, 5)
print("Sleep :", name, get_epoch_ms(), slp)
await asyncio.sleep(slp)
except Exception as e:
print("Error :", e)
print("Finish :", name, get_epoch_ms())
async def main():
i = 0
while True:
i += 1
# Todo : this line should be change
await do_somthing('T' + str(i))
await asyncio.sleep(period)
asyncio.get_event_loop().run_until_complete(main())
答案 0 :(得分:0)
调用asyncio.create_task
而不是await
创建协程,以生成在后台运行的任务对象。在下一次迭代时,您可以检查任务是否完成,并相应地等待/取消。 (否则,asyncio将抱怨未完成的任务被垃圾回收。)
答案 1 :(得分:0)
您的问题是使用run_until_complete(main())
不能满足您的并发目的,因此假设您的协同程序任务(do_somthing()
)绑定到5
,您的代码将如下所示:
import time
from random import randint
period = 1 # Second
def get_epoch_ms():
return int(time.time() * 1000.0)
async def do_somthing(name):
print("Start :", name, get_epoch_ms())
try:
# Do something which may takes more than 1 secs.
slp = randint(1, 5)
print("Sleep :", name, get_epoch_ms(), slp)
await asyncio.sleep(slp)
except Exception as e:
print("Error :", e)
print("Finish :", name, get_epoch_ms())
loop = asyncio.get_event_loop()
futures = [loop.create_task(do_somthing('T' + str(i)))
for i in range(5)]
loop.run_forever()
for f in futures:
f.cancel()
这是其输出中的并发工作流:
Start : T0 1558937750705
Sleep : T0 1558937750705 5
Start : T1 1558937750705
Sleep : T1 1558937750705 1
Start : T2 1558937750705
Sleep : T2 1558937750705 4
Start : T3 1558937750705
Sleep : T3 1558937750705 5
Start : T4 1558937750705
Sleep : T4 1558937750705 5
Finish : T1 1558937751707
Finish : T2 1558937754709
Finish : T0 1558937755707
Finish : T3 1558937755708
Finish : T4 1558937755708
但是,如果协程任务不受限制,则可以执行以下操作:
...
async def main(loop):
i = 0
while True:
i += 1
loop.create_task(do_somthing('T' + str(i)))
await asyncio.sleep(period)
loop = asyncio.get_event_loop()
loop.run_until_complete(main(loop))