mirror of
https://github.com/PiBrewing/craftbeerpi4.git
synced 2024-11-10 01:17:42 +01:00
115 lines
3.6 KiB
Python
115 lines
3.6 KiB
Python
import asyncio
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import sys
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from types import TracebackType
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from typing import Optional, Type, Any # noqa
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__version__ = '3.0.1'
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PY_37 = sys.version_info >= (3, 7)
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class timeout:
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"""timeout context manager.
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Useful in cases when you want to apply timeout logic around block
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of code or in cases when asyncio.wait_for is not suitable. For example:
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>>> with timeout(0.001):
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... async with aiohttp.get('https://github.com') as r:
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... await r.text()
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timeout - value in seconds or None to disable timeout logic
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loop - asyncio compatible event loop
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"""
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def __init__(self, timeout: Optional[float],
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*, loop: Optional[asyncio.AbstractEventLoop] = None) -> None:
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self._timeout = timeout
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if loop is None:
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loop = asyncio.get_event_loop()
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self._loop = loop
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self._task = None # type: Optional[asyncio.Task[Any]]
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self._cancelled = False
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self._cancel_handler = None # type: Optional[asyncio.Handle]
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self._cancel_at = None # type: Optional[float]
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def __enter__(self) -> 'timeout':
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return self._do_enter()
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def __exit__(self,
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exc_type: Type[BaseException],
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exc_val: BaseException,
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exc_tb: TracebackType) -> Optional[bool]:
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self._do_exit(exc_type)
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return None
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async def __aenter__(self) -> 'timeout':
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return self._do_enter()
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async def __aexit__(self,
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exc_type: Type[BaseException],
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exc_val: BaseException,
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exc_tb: TracebackType) -> None:
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self._do_exit(exc_type)
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@property
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def expired(self) -> bool:
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return self._cancelled
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@property
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def remaining(self) -> Optional[float]:
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if self._cancel_at is not None:
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return max(self._cancel_at - self._loop.time(), 0.0)
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else:
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return None
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def _do_enter(self) -> 'timeout':
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# Support Tornado 5- without timeout
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# Details: https://github.com/python/asyncio/issues/392
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if self._timeout is None:
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return self
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self._task = current_task(self._loop)
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if self._task is None:
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raise RuntimeError('Timeout context manager should be used '
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'inside a task')
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if self._timeout <= 0:
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self._loop.call_soon(self._cancel_task)
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return self
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self._cancel_at = self._loop.time() + self._timeout
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self._cancel_handler = self._loop.call_at(
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self._cancel_at, self._cancel_task)
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return self
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def _do_exit(self, exc_type: Type[BaseException]) -> None:
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if exc_type is asyncio.CancelledError and self._cancelled:
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self._cancel_handler = None
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self._task = None
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raise asyncio.TimeoutError
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if self._timeout is not None and self._cancel_handler is not None:
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self._cancel_handler.cancel()
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self._cancel_handler = None
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self._task = None
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return None
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def _cancel_task(self) -> None:
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if self._task is not None:
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self._task.cancel()
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self._cancelled = True
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def current_task(loop: asyncio.AbstractEventLoop) -> 'asyncio.Task[Any]':
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if PY_37:
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task = asyncio.current_task(loop=loop) # type: ignore
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else:
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task = asyncio.Task.current_task(loop=loop)
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if task is None:
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# this should be removed, tokio must use register_task and family API
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if hasattr(loop, 'current_task'):
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task = loop.current_task() # type: ignore
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return task
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