wehub-resource-sync
48 lines
1.5 KiB
Python
48 lines
1.5 KiB
Python
import time
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from collections import deque
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from typing import Deque, Tuple
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class TimeWindowAverageCalculator:
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"""A utility class to calculate the average of values reported in a time window."""
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def __init__(
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self,
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window_s: float,
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):
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assert window_s > 0
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# Time window in seconds.
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self._window_s = window_s
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# Buffer the values reported in the time window, each value is a
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# tuple of (time, value).
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self._values: Deque[Tuple[float, float]] = deque()
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# Sum of all values in the time window.
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self._sum: float = 0
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def report(self, value: float):
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"""Report a value to the calculator."""
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now = time.time()
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self._values.append((now, value))
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self._sum += value
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self._trim(now)
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def get_average(self):
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"""Get the average of values reported in the time window,
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or None if no values reported in the last time window.
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"""
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self._trim(time.time())
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if len(self._values) == 0:
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return None
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return self._sum / len(self._values)
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def _trim(self, now):
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"""Remove the values reported outside of the time window."""
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while len(self._values) > 0 and now - self._values[0][0] > self._window_s:
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_, value = self._values.popleft()
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self._sum -= value
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# Set sum to 0 if there are no values to avoid accumulated floating-point error
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# from repeated += / -= operations.
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if len(self._values) == 0:
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self._sum = 0
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