python如何定时异步执行任务

import asyncio
import functools

# 下面我们将借助partial函数来说明如何使用关键字参数
def callback(arg, *, kwarg='default'):
    print(f'callback with {arg} and {kwarg}')

async def main(loop):
    print('register callbacks')
    # 还是通过get_event_loop 获取Eventloop
    loop.call_soon(callback, 1)
    # 使用partial函数，对kwarg参数进行控制
    wrapped = functools.partial(callback, kwarg='not default')
    loop.call_soon(wrapped, 2)
    # 上一篇中说过的，await用于等待，sleep也不是time.sleep
    await asyncio.sleep(0.1)

event_loop = asyncio.get_event_loop()
try:
    print('entering event loop')
    event_loop.run_until_complete(main(event_loop))
finally:
    print('closing event loop')
    event_loop.close()

import asyncio

def callback(n):
    print(f'callback with {n}')

async def main(loop):
    print('register callbacks')
    # 延迟0.2秒执行
    # 执行完后调用callback函数
    # callback的参数n
    loop.call_later(0.2, callback, 1)
    loop.call_later(0.1, callback, 2)
    # 再来看下和call_soon的区别
    loop.call_soon(callback, 3)

    await asyncio.sleep(0.4)

event_loop = asyncio.get_event_loop()
try:
    print('starting event_loop')
    event_loop.run_until_complete(main(event_loop))
finally:
    print('closing event_loop')
    event_loop.close()

import asyncio
import time

def callback(n, loop):
    print(f'callback with {n} at {loop.time()}')

async def main(loop):
    # 使用loop.time 而不是time和datetime模块
    now = loop.time()
    print(f'time模块的时间: {time.time()}')
    print(f'loop.time的时间: {now}')

    print('register callbacks')
    # 使用call_at指定当前时间后的0.2秒执行
    # 执行完了回掉callback
    # callback的n和loop参数
    loop.call_at(now + 0.2, callback, 1, loop)
    loop.call_at(now + 0.1, callback, 2, loop)
    # 和call_soon对比一下
    loop.call_soon(callback, 3, loop)

    await asyncio.sleep(1)


event_loop = asyncio.get_event_loop()
try:
    print('starting event_loop')
    event_loop.run_until_complete(main(event_loop))
finally:
    print('closing event_loop')
    event_loop.close()