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Future/generator expansion inside asyncio.coroutine
import asyncio
import contextlib
@asyncio.coroutine
def return_coroutine_object():
@asyncio.coroutine
def g():
yield from asyncio.sleep(0.01)
return "return_coroutine_object"
return g()
@asyncio.coroutine
def return_future():
fut = asyncio.Future()
fut.set_result("return_future")
return fut
@asyncio.coroutine
def generator_return_future():
yield from asyncio.sleep(0.01)
fut = asyncio.Future()
fut.set_result("generator_return_future")
return fut
if __name__ == "__main__":
loop = asyncio.get_event_loop()
with contextlib.closing(loop):
print("return_future:",
loop.run_until_complete(return_future()))
print("generator_return_future:",
loop.run_until_complete(generator_return_future()))
print("return_coroutine_object:",
loop.run_until_complete(return_coroutine_object()))
$ PYTHONASYNCIODEBUG=X python3 return_await.py
<CoroWrapper return_coroutine_object.<locals>.g() running at return_await.py:7, created at return_await.py:12> was never yielded from
Coroutine object created at (most recent call last):
File "return_await.py", line 44, in <module>
loop.run_until_complete(return_coroutine_object()))
File "/usr/lib/python3.4/asyncio/base_events.py", line 304, in run_until_complete
self.run_forever()
File "/usr/lib/python3.4/asyncio/base_events.py", line 276, in run_forever
self._run_once()
File "/usr/lib/python3.4/asyncio/base_events.py", line 1164, in _run_once
handle._run()
File "/usr/lib/python3.4/asyncio/events.py", line 120, in _run
self._callback(*self._args)
File "/usr/lib/python3.4/asyncio/tasks.py", line 238, in _step
result = next(coro)
File "/usr/lib/python3.4/asyncio/coroutines.py", line 79, in __next__
return next(self.gen)
File "/usr/lib/python3.4/asyncio/coroutines.py", line 141, in coro
res = func(*args, **kw)
File "return_await.py", line 12, in return_coroutine_object
return g()
return_future: return_future
generator_return_future: <Future finished result='generator_return_future' created at return_await.py:27>
return_coroutine_object: <CoroWrapper return_coroutine_object.<locals>.g() running at return_await.py:7, created at return_await.py:12>
$
$ python3 return_await.py
return_future: return_future
generator_return_future: <Future finished result='generator_return_future'>
return_coroutine_object: return_coroutine_object
$
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