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|
"""
Asyncio compatibility functions.
"""
import asyncio
from greenlet import GreenletExit
from .greenthread import spawn, getcurrent
from .event import Event
from .hubs import get_hub
from .hubs.asyncio import Hub as AsyncioHub
__all__ = ["spawn_for_awaitable"]
def spawn_for_awaitable(coroutine):
"""
Take a coroutine or some other object that can be awaited
(``asyncio.Future``, ``asyncio.Task``), and turn it into a ``GreenThread``.
Known limitations:
* The coroutine/future/etc. don't run in their own
greenlet/``GreenThread``.
* As a result, things like ``eventlet.Lock``
won't work correctly inside ``async`` functions, thread ids aren't
meaningful, and so on.
"""
if not isinstance(get_hub(), AsyncioHub):
raise RuntimeError(
"This API only works with eventlet's asyncio hub. "
+ "To use it, set an EVENTLET_HUB=asyncio environment variable."
)
def _run():
# Convert the coroutine/Future/Task we're wrapping into a Future.
future = asyncio.ensure_future(coroutine, loop=asyncio.get_running_loop())
# Ensure killing the GreenThread cancels the Future:
def _got_result(gthread):
try:
gthread.wait()
except GreenletExit:
future.cancel()
getcurrent().link(_got_result)
# Wait until the Future has a result.
has_result = Event()
future.add_done_callback(lambda _: has_result.send(True))
has_result.wait()
# Return the result of the Future (or raise an exception if it had an
# exception).
return future.result()
# Start a GreenThread:
return spawn(_run)
|
