92 lines
2.6 KiB
Python
92 lines
2.6 KiB
Python
import time
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from math import isfinite
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from typing import Callable, Optional
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from .logger import rootlog
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class PollingConditionError(Exception):
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pass
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class PollingCondition:
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condition: Callable[[], bool]
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seconds_interval: float
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description: Optional[str]
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last_called: float
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entry_count: int
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def __init__(
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self,
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condition: Callable[[], Optional[bool]],
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seconds_interval: float = 2.0,
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description: Optional[str] = None,
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):
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self.condition = condition # type: ignore
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self.seconds_interval = seconds_interval
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if description is None:
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if condition.__doc__:
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self.description = condition.__doc__
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else:
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self.description = condition.__name__
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else:
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self.description = str(description)
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self.last_called = float("-inf")
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self.entry_count = 0
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def check(self, force: bool = False) -> bool:
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if (self.entered or not self.overdue) and not force:
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return True
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with self, rootlog.nested(self.nested_message):
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time_since_last = time.monotonic() - self.last_called
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last_message = (
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f"Time since last: {time_since_last:.2f}s"
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if isfinite(time_since_last)
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else "(not called yet)"
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)
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rootlog.info(last_message)
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try:
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res = self.condition() # type: ignore
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except Exception:
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res = False
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res = res is None or res
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rootlog.info(self.status_message(res))
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return res
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def maybe_raise(self) -> None:
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if not self.check():
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raise PollingConditionError(self.status_message(False))
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def status_message(self, status: bool) -> str:
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return f"Polling condition {'succeeded' if status else 'failed'}: {self.description}"
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@property
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def nested_message(self) -> str:
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nested_message = ["Checking polling condition"]
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if self.description is not None:
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nested_message.append(repr(self.description))
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return " ".join(nested_message)
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@property
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def overdue(self) -> bool:
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return self.last_called + self.seconds_interval < time.monotonic()
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@property
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def entered(self) -> bool:
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# entry_count should never dip *below* zero
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assert self.entry_count >= 0
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return self.entry_count > 0
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def __enter__(self) -> None:
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self.entry_count += 1
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def __exit__(self, exc_type, exc_value, traceback) -> None: # type: ignore
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assert self.entered
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self.entry_count -= 1
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self.last_called = time.monotonic()
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