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