tasks.py

# -*- coding:utf-8 -*-
import asyncio
from asyncio.futures import Future
from functools import partial


@asyncio.coroutine
def open_content():
    yield from asyncio.sleep(2)
    print("[0] open")


@asyncio.coroutine
def push_content():
    yield from asyncio.sleep(0.5)
    print("[1] push_content")


@asyncio.coroutine
def close_content():
    print("[2] close")


@asyncio.coroutine
def run():
    yield from open_content()
    yield from push_content()
    yield from close_content()
    yield from asyncio.sleep(1)
    loop.stop()


@asyncio.coroutine
def run_broken():
    asyncio.async(open_content())
    asyncio.async(push_content())
    asyncio.async(close_content())
    yield from asyncio.sleep(1)
    loop.stop()


@asyncio.coroutine
def run_parallel():
    sentinel = Future(loop=loop)
    tasks = [asyncio.async(open_content()),
             asyncio.async(push_content()),
             asyncio.async(close_content())]
    results = [None] * len(tasks)
    N = 0

    def _done_callback(i, f):
        nonlocal N
        results[i] = f._result
        N += 1
        if N == len(tasks):
            sentinel.set_result(results)

    for i, t in enumerate(tasks):
        t.add_done_callback(partial(_done_callback, i))

    yield from sentinel
    loop.stop()


@asyncio.coroutine
def run_parallel2():
    yield from asyncio.gather(open_content(),
                              push_content(),
                              close_content())
    loop.stop()


loop = asyncio.get_event_loop()
asyncio.async(run_parallel2())
loop.run_forever()
print("Pending tasks at exit: %s" % asyncio.Task.all_tasks(loop))
loop.close()