我如何 运行 在 Twisted 的 asyncioreactor 之上编写 asyncio 库代码？
How can I run asyncio library code on top of Twisted's asyncioreactor?
我已经设法 import/install Twisted 的 asyncioreactor 并执行了一个简单的异步函数：
from twisted.internet import asyncioreactor
asyncioreactor.install()
from twisted.internet import task
from twisted.internet.defer import inlineCallbacks
from twisted.internet.defer import ensureDeferred
async def sleepy(reactor):
print("SLEEPING")
await task.deferLater(reactor, 3.0, lambda: None)
print("done sleep")
return 42
@task.react
def main(reactor):
d = ensureDeferred(sleepy(reactor))
d.addCallback(print)
return d
我想在上述代码中混入一个 asyncio 库，例如 asyncio.sleep。我尝试了以下方法：
from twisted.internet import asyncioreactor
asyncioreactor.install()
from twisted.internet import task
from twisted.internet.defer import inlineCallbacks
from twisted.internet.defer import ensureDeferred
import asyncio
async def sleepy(reactor):
print("SLEEPING")
await asyncio.sleep(3)
print("done sleep")
return 42
@task.react
def main(reactor):
d = ensureDeferred(sleepy(reactor))
d.addCallback(print)
return d
产生以下错误：
$ python test.py
SLEEPING
main function encountered error
Traceback (most recent call last):
File "test.py", line 16, in <module>
@task.react
File "/Users/blz/.pyenv/versions/3.6.0/lib/python3.6/site-packages/twisted/internet/task.py", line 908, in react
finished = main(_reactor, *argv)
File "test.py", line 18, in main
d = ensureDeferred(sleepy(reactor))
File "/Users/blz/.pyenv/versions/3.6.0/lib/python3.6/site-packages/twisted/internet/defer.py", line 823, in ensureDeferred
return _inlineCallbacks(None, coro, Deferred())
--- <exception caught here> ---
File "/Users/blz/.pyenv/versions/3.6.0/lib/python3.6/site-packages/twisted/internet/defer.py", line 1301, in _inlineCallbacks
result = g.send(result)
File "test.py", line 11, in sleepy
await asyncio.sleep(3)
File "/Users/blz/.pyenv/versions/3.6.0/lib/python3.6/asyncio/tasks.py", line 476, in sleep
return (yield from future)
builtins.AssertionError: yield from wasn't used with future
很公平，我想，所以我尝试将 await asyncio.sleep(3) 与 await ensureDeferred(asyncio.sleep(3)) 和 await asyncio.ensure_future(asyncio.sleep(3)) 交换，但我得到了完全相同的错误。
如何在 asyncioreactor 使用的同一事件循环上将 aio 协程 (and/or Future) 安排到 运行？
哇，您遇到了一个有趣的边角案例！
通过使用 asyncio.sleep() 你触发了一些有趣的行为。
我认为您可能发现了一个错误
Twisted 与 Python 3 asyncioreactor 和 async/await 的集成。
您可能希望跟进 Twisted 邮件列表中的 Twisted 开发人员。
我不是 100% 确定，但这是我的想法。
asyncio.sleep() 的实现与 Python 紧密耦合 3
异步实现。它使用 asyncio.Future（类似于 Twisted 的延迟），并使用 get_event_loop()（类似于 Twisted 的反应器）。
asyncio.sleep是这样实现的：
@coroutine
def sleep(delay, result=None, *, loop=None):
"""Coroutine that completes after a given time (in seconds)."""
if delay == 0:
yield
return result
if loop is None:
loop = events.get_event_loop()
future = loop.create_future()
h = future._loop.call_later(delay,
futures._set_result_unless_cancelled,
future, result)
try:
return (yield from future)
finally:
h.cancel()
我稍微更改了您的代码示例以通过 Twisted 的
异步反应器事件循环进入 asyncio.sleep():
from twisted.internet import asyncioreactor
asyncioreactor.install()
from twisted.internet import reactor
from twisted.internet import task
from twisted.internet.defer import inlineCallbacks
from twisted.internet.defer import ensureDeferred
import asyncio
async def sleepy(reactor):
print("SLEEPING")
await asyncio.sleep(3, loop=reactor._asyncioEventloop)
print("done sleep")
return 42
@task.react
def main(reactor):
d = ensureDeferred(sleepy(reactor))
d.addCallback(print)
return d
我仍然遇到和你一样的错误：builtins.AssertionError: yield from wasn't used with future
堆栈跟踪看起来像：
main function encountered error
Traceback (most recent call last):
File "b.py", line 16, in <module>
@task.react
File "/Users/crodrigues/twisted8/src/twisted/internet/task.py", line 908, in react
finished = main(_reactor, *argv)
File "b.py", line 19, in main
d = ensureDeferred(sleepy(reactor))
File "/Users/crodrigues/twisted8/src/twisted/internet/defer.py", line 823, in ensureDeferred
return _inlineCallbacks(None, coro, Deferred())
--- <exception caught here> ---
File "/Users/crodrigues/twisted8/src/twisted/internet/defer.py", line 1301, in _inlineCallbacks
result = g.send(result)
File "b.py", line 12, in sleepy
await asyncio.sleep(3, loop=reactor._asyncioEventloop)
File "/usr/local/Cellar/python3/3.6.0/Frameworks/Python.framework/Versions/3.6/lib/python3.6/asyncio/tasks.py", line 478, in sleep
return (yield from future)
builtins.AssertionError: yield from wasn't used with future
我认为 asyncio.sleep() 是一个协程，应该 运行 完成
在 asyncio 循环上，但这并没有发生在这里，因此断言。
我认为问题是由 result = g.send(result) 引入的。
我不确定您是否可以 send() 到这样的协程并期望它能正常工作。
我建议您在 Twisted 邮件列表上提问以获得更详细的反馈。
so I tried swapping await asyncio.sleep(3) with await
ensureDeferred(asyncio.sleep(3)) and await
asyncio.ensure_future(asyncio.sleep(3))
你已经差不多了，你应该把两者结合起来，使用 Deferred.fromFuture 而不是 ensureDeferred:
await Deferred.fromFuture(asyncio.ensure_future(asyncio.sleep(3)))
规则是，async def 函数 运行ning 在 Twisted 上下文中（使用 ensureDeferred）只能在 Deferred 上等待，而 async def 函数 运行ning 在异步上下文中（使用 ensure_future）仅在异步 Future 上（总是可以等待其他协程对象（async def 函数调用的结果），但链最终将导致 Deferred/Future)。要从 asyncio Future 转换为 Deferred 使用 Deferred.fromFuture 并转换为 asyncio Future 使用 Deferred.asFuture.
可以将上下文从一个上下文切换到另一个上下文。在这个（人为的）示例中，我们从 sleepy_twisted 运行 开始
Twisted 上下文，它执行 Twisted 睡眠，然后它切换到异步上下文到 运行 sleepy_asyncio，它执行异步睡眠，但随后再次切换到 Twisted 上下文以进行 Twisted 睡眠：
from twisted.internet import asyncioreactor, task
from twisted.internet.defer import inlineCallbacks, ensureDeferred, Deferred
import asyncio
asyncioreactor.install()
async def sleepy_asyncio(reactor):
print("Sleep 2")
await asyncio.sleep(1)
print("Sleep 3")
await Deferred.asFuture(task.deferLater(reactor, 1, lambda: None), loop=asyncio.get_running_loop())
async def sleepy_twisted(reactor):
print("Sleep 1")
await task.deferLater(reactor, 1, lambda: None)
await Deferred.fromFuture(asyncio.ensure_future(sleepy_asyncio(reactor)))
print("done")
@task.react
def main(reactor):
return ensureDeferred(sleepy_twisted(reactor))
我已经设法 import/install Twisted 的 asyncioreactor 并执行了一个简单的异步函数：
from twisted.internet import asyncioreactor
asyncioreactor.install()
from twisted.internet import task
from twisted.internet.defer import inlineCallbacks
from twisted.internet.defer import ensureDeferred
async def sleepy(reactor):
print("SLEEPING")
await task.deferLater(reactor, 3.0, lambda: None)
print("done sleep")
return 42
@task.react
def main(reactor):
d = ensureDeferred(sleepy(reactor))
d.addCallback(print)
return d
我想在上述代码中混入一个 asyncio 库，例如 asyncio.sleep。我尝试了以下方法：
from twisted.internet import asyncioreactor
asyncioreactor.install()
from twisted.internet import task
from twisted.internet.defer import inlineCallbacks
from twisted.internet.defer import ensureDeferred
import asyncio
async def sleepy(reactor):
print("SLEEPING")
await asyncio.sleep(3)
print("done sleep")
return 42
@task.react
def main(reactor):
d = ensureDeferred(sleepy(reactor))
d.addCallback(print)
return d
产生以下错误：
$ python test.py
SLEEPING
main function encountered error
Traceback (most recent call last):
File "test.py", line 16, in <module>
@task.react
File "/Users/blz/.pyenv/versions/3.6.0/lib/python3.6/site-packages/twisted/internet/task.py", line 908, in react
finished = main(_reactor, *argv)
File "test.py", line 18, in main
d = ensureDeferred(sleepy(reactor))
File "/Users/blz/.pyenv/versions/3.6.0/lib/python3.6/site-packages/twisted/internet/defer.py", line 823, in ensureDeferred
return _inlineCallbacks(None, coro, Deferred())
--- <exception caught here> ---
File "/Users/blz/.pyenv/versions/3.6.0/lib/python3.6/site-packages/twisted/internet/defer.py", line 1301, in _inlineCallbacks
result = g.send(result)
File "test.py", line 11, in sleepy
await asyncio.sleep(3)
File "/Users/blz/.pyenv/versions/3.6.0/lib/python3.6/asyncio/tasks.py", line 476, in sleep
return (yield from future)
builtins.AssertionError: yield from wasn't used with future
很公平，我想，所以我尝试将 await asyncio.sleep(3) 与 await ensureDeferred(asyncio.sleep(3)) 和 await asyncio.ensure_future(asyncio.sleep(3)) 交换，但我得到了完全相同的错误。
如何在 asyncioreactor 使用的同一事件循环上将 aio 协程 (and/or Future) 安排到 运行？
哇，您遇到了一个有趣的边角案例！ 通过使用 asyncio.sleep() 你触发了一些有趣的行为。
我认为您可能发现了一个错误 Twisted 与 Python 3 asyncioreactor 和 async/await 的集成。 您可能希望跟进 Twisted 邮件列表中的 Twisted 开发人员。
我不是 100% 确定，但这是我的想法。
asyncio.sleep() 的实现与 Python 紧密耦合 3 异步实现。它使用 asyncio.Future（类似于 Twisted 的延迟），并使用 get_event_loop()（类似于 Twisted 的反应器）。
asyncio.sleep是这样实现的：
@coroutine
def sleep(delay, result=None, *, loop=None):
"""Coroutine that completes after a given time (in seconds)."""
if delay == 0:
yield
return result
if loop is None:
loop = events.get_event_loop()
future = loop.create_future()
h = future._loop.call_later(delay,
futures._set_result_unless_cancelled,
future, result)
try:
return (yield from future)
finally:
h.cancel()
我稍微更改了您的代码示例以通过 Twisted 的 异步反应器事件循环进入 asyncio.sleep():
from twisted.internet import asyncioreactor
asyncioreactor.install()
from twisted.internet import reactor
from twisted.internet import task
from twisted.internet.defer import inlineCallbacks
from twisted.internet.defer import ensureDeferred
import asyncio
async def sleepy(reactor):
print("SLEEPING")
await asyncio.sleep(3, loop=reactor._asyncioEventloop)
print("done sleep")
return 42
@task.react
def main(reactor):
d = ensureDeferred(sleepy(reactor))
d.addCallback(print)
return d
我仍然遇到和你一样的错误：builtins.AssertionError: yield from wasn't used with future
堆栈跟踪看起来像：
main function encountered error
Traceback (most recent call last):
File "b.py", line 16, in <module>
@task.react
File "/Users/crodrigues/twisted8/src/twisted/internet/task.py", line 908, in react
finished = main(_reactor, *argv)
File "b.py", line 19, in main
d = ensureDeferred(sleepy(reactor))
File "/Users/crodrigues/twisted8/src/twisted/internet/defer.py", line 823, in ensureDeferred
return _inlineCallbacks(None, coro, Deferred())
--- <exception caught here> ---
File "/Users/crodrigues/twisted8/src/twisted/internet/defer.py", line 1301, in _inlineCallbacks
result = g.send(result)
File "b.py", line 12, in sleepy
await asyncio.sleep(3, loop=reactor._asyncioEventloop)
File "/usr/local/Cellar/python3/3.6.0/Frameworks/Python.framework/Versions/3.6/lib/python3.6/asyncio/tasks.py", line 478, in sleep
return (yield from future)
builtins.AssertionError: yield from wasn't used with future
我认为 asyncio.sleep() 是一个协程，应该 运行 完成 在 asyncio 循环上，但这并没有发生在这里，因此断言。
我认为问题是由 result = g.send(result) 引入的。 我不确定您是否可以 send() 到这样的协程并期望它能正常工作。
我建议您在 Twisted 邮件列表上提问以获得更详细的反馈。
so I tried swapping await asyncio.sleep(3) with await ensureDeferred(asyncio.sleep(3)) and await asyncio.ensure_future(asyncio.sleep(3))
你已经差不多了，你应该把两者结合起来，使用 Deferred.fromFuture 而不是 ensureDeferred:
await Deferred.fromFuture(asyncio.ensure_future(asyncio.sleep(3)))
规则是，async def 函数 运行ning 在 Twisted 上下文中（使用 ensureDeferred）只能在 Deferred 上等待，而 async def 函数 运行ning 在异步上下文中（使用 ensure_future）仅在异步 Future 上（总是可以等待其他协程对象（async def 函数调用的结果），但链最终将导致 Deferred/Future)。要从 asyncio Future 转换为 Deferred 使用 Deferred.fromFuture 并转换为 asyncio Future 使用 Deferred.asFuture.
可以将上下文从一个上下文切换到另一个上下文。在这个（人为的）示例中，我们从 sleepy_twisted 运行 开始
Twisted 上下文，它执行 Twisted 睡眠，然后它切换到异步上下文到 运行 sleepy_asyncio，它执行异步睡眠，但随后再次切换到 Twisted 上下文以进行 Twisted 睡眠：
from twisted.internet import asyncioreactor, task
from twisted.internet.defer import inlineCallbacks, ensureDeferred, Deferred
import asyncio
asyncioreactor.install()
async def sleepy_asyncio(reactor):
print("Sleep 2")
await asyncio.sleep(1)
print("Sleep 3")
await Deferred.asFuture(task.deferLater(reactor, 1, lambda: None), loop=asyncio.get_running_loop())
async def sleepy_twisted(reactor):
print("Sleep 1")
await task.deferLater(reactor, 1, lambda: None)
await Deferred.fromFuture(asyncio.ensure_future(sleepy_asyncio(reactor)))
print("done")
@task.react
def main(reactor):
return ensureDeferred(sleepy_twisted(reactor))