python3 asyncio

1. 引入 asyncio 模块

import asyncio

2. 定义一个协程函数

async def do_something(x):
    print('waiting: ', x)

    await asyncio.sleep(x)
    return x

3. 协程不能直接运行，把协程加入到事件循环（loop）。asyncio.get_event_loop 方法可以创建一个事件循环，然后使用 run_until_complete 将协程注册到事件循环，并启动事件循环。
   使用 asyncio.ensure_future(coroutine) 创建 task ，方便在后面读取任务结果

coroutine1 = do_something(1)
coroutine2 = do_something(4)

tasks = [
    asyncio.ensure_future(coroutine1),
    asyncio.ensure_future(coroutine2)
]

loop = asyncio.get_event_loop()
loop.run_until_complete(asyncio.wait(tasks))

4. 获取 task 执行结果，并打印

for task in tasks:
    print('task result: ', task.result())

main.py 完整例子

import asyncio

import time
print('1')
now = lambda: time.time()

async def do_something(x):
    print('waiting: ', x)

    await asyncio.sleep(x)
    return x

start = now()
print('2')
coroutine1 = do_something(1)
coroutine2 = do_something(4)

tasks = [
    asyncio.ensure_future(coroutine1),
    asyncio.ensure_future(coroutine2)
]

loop = asyncio.get_event_loop()
loop.run_until_complete(asyncio.wait(tasks))

print('123')
time.sleep(10)
print('333333')


for task in tasks:
    print('task result: ', task.result())

print('time: ', now() - start)