124 lines
4.4 KiB
Python
124 lines
4.4 KiB
Python
"""事件聚合器 (MVP-1 / P5 简化版)
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时间窗口去重: 对同一 ``(source_id, event_type, track_id_or_bbox_hash)``
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在配置窗口内只保留一条预警事件，重复命中时更新 ``last_seen``
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与 ``occurrence_count``，避免预警刷屏。
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后续 MVP-2 会扩展空间邻近合并、置信度加权融合等能力。
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"""
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from __future__ import annotations
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import logging
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import time
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from collections import OrderedDict
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from typing import Dict, List, Optional, Tuple
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from models.event_schemas import AlertEvent, UnifiedDetection
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logger = logging.getLogger(__name__)
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_AggKey = Tuple[Optional[str], str, str]
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class EventAggregator:
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"""基于时间窗口的预警去重 / 聚合器。
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Args:
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dedup_window_seconds: 去重窗口 (秒)，同 key 在窗口内不会重复产出
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max_active_events: 内存中最大活跃事件数，超过时按 LRU 淘汰
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"""
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def __init__(
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self,
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dedup_window_seconds: float = 30.0,
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max_active_events: int = 1000,
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) -> None:
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self.dedup_window_seconds = max(0.0, dedup_window_seconds)
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self.max_active_events = max(1, max_active_events)
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# 按插入顺序保存以便 LRU 淘汰
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self._active: "OrderedDict[_AggKey, AlertEvent]" = OrderedDict()
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# ------------------------------------------------------------------
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# 主入口
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# ------------------------------------------------------------------
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def aggregate(self, alerts: List[AlertEvent]) -> List[AlertEvent]:
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"""聚合一批预警事件，返回去重后真正应当对外发出的事件。"""
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now = time.time()
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self._evict_expired(now)
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emitted: List[AlertEvent] = []
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for alert in alerts:
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key = self._make_key(alert)
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existing = self._active.get(key)
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if existing is None:
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self._active[key] = alert
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self._active.move_to_end(key)
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emitted.append(alert)
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if len(self._active) > self.max_active_events:
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dropped_key, _ = self._active.popitem(last=False)
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logger.debug("聚合器 LRU 淘汰事件: %s", dropped_key)
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else:
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# 窗口内重复：仅更新统计
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existing.last_seen = now
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existing.occurrence_count += 1
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if alert.confidence > existing.confidence:
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existing.confidence = alert.confidence
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self._active.move_to_end(key)
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return emitted
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# ------------------------------------------------------------------
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# 内部
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# ------------------------------------------------------------------
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@staticmethod
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def _make_key(alert: AlertEvent) -> _AggKey:
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if alert.detections:
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target_id = EventAggregator._target_identity(alert.detections[0])
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else:
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target_id = "no_target"
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return (alert.source_id, alert.event_type.value, target_id)
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@staticmethod
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def _target_identity(det: UnifiedDetection) -> str:
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"""构造目标稳定标识：优先 track_id，否则用 bbox 网格哈希。"""
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if det.track_id is not None:
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return f"t{det.track_id}"
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# 按 50px 栅格归一，避免微小抖动导致漏聚合
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cx, cy = det.bbox.center
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return f"g{int(cx) // 50}_{int(cy) // 50}_{det.class_name}"
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def _evict_expired(self, now: float) -> None:
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if self.dedup_window_seconds <= 0:
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self._active.clear()
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return
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# 基于 first_seen 判断窗口过期：保证 "同一目标 30 秒内只产生 1 条事件"，
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# 同时窗口到期后允许再次触发 (而不会因为不断收到同类检测而无限延期)。
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expired_keys = [
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key
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for key, alert in self._active.items()
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if now - alert.first_seen > self.dedup_window_seconds
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]
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for key in expired_keys:
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self._active.pop(key, None)
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# ------------------------------------------------------------------
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# 自省
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# ------------------------------------------------------------------
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@property
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def active_count(self) -> int:
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return len(self._active)
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def snapshot(self) -> Dict[str, AlertEvent]:
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"""返回当前活跃事件的快照 (用于调试 / 监控)。"""
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return {f"{k[0]}|{k[1]}|{k[2]}": v for k, v in self._active.items()}
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__all__ = ["EventAggregator"]
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