69 lines
2.2 KiB
Python
69 lines
2.2 KiB
Python
# -*- coding: utf-8 -*-
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"""看板聚合结果的内存 TTL 缓存。
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缓存键包含数据库路径和数据版本；版本存放在 ``kv``（``cache:v:<group>``），
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因此同一个进程内的调度任务和 Web 线程都会看到一致的失效，跨进程的 CLI
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导入也可以通过提升版本让旧缓存失效。
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"""
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from __future__ import annotations
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import threading
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import time
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from typing import Any, Callable, Hashable
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TTL_VIDEOS = 3600
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TTL_FANS = 86400
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class TTLCache:
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def __init__(self, *, clock: Callable[[], float] = time.time, max_items: int = 256) -> None:
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self._clock = clock
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self._max_items = max(16, int(max_items))
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self._lock = threading.RLock()
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self._items: dict[Hashable, tuple[float, Any]] = {}
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def get(self, key: Hashable) -> Any | None:
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with self._lock:
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entry = self._items.get(key)
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if entry is None:
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return None
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expires_at, value = entry
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if expires_at <= self._clock():
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self._items.pop(key, None)
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return None
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return value
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def set(self, key: Hashable, ttl: float, value: Any) -> None:
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with self._lock:
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now = self._clock()
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self._items[key] = (now + float(ttl), value)
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if len(self._items) > self._max_items:
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expired = [k for k, (exp, _) in self._items.items() if exp <= now]
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for item in expired:
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self._items.pop(item, None)
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if len(self._items) > self._max_items:
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oldest = sorted(self._items.items(), key=lambda kv: kv[1][0])
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for item, _ in oldest[: len(self._items) - self._max_items]:
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self._items.pop(item, None)
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def clear(self) -> None:
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with self._lock:
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self._items.clear()
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def __len__(self) -> int:
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with self._lock:
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return len(self._items)
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DASHBOARD_CACHE = TTLCache()
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def build_cache_key(
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scope: str,
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group: str,
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version: int,
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params: dict[str, Any] | None = None,
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) -> tuple[Any, ...]:
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frozen = tuple(sorted((str(key), str(value)) for key, value in (params or {}).items()))
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return (scope, group, int(version), frozen) |