339 lines
10 KiB
Python
339 lines
10 KiB
Python
"""
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基于内存的 Agent 缓存管理模块
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使用 cachetools 库实现 TTLCache 和 LRUCache
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"""
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import os
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import logging
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import time
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import threading
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from typing import Any, Optional, Dict, Tuple
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from collections import OrderedDict
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from datetime import datetime, timedelta
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import cachetools
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logger = logging.getLogger('app')
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class AgentMemoryCacheManager:
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"""
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使用 cachetools 实现的内存缓存管理器
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- 基于内存存储，访问速度快
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- 支持自动过期时间（TTL）
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- 支持缓存大小限制和 LRU 淘汰策略
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- 支持访问时自动延长过期时间
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- 线程安全（使用 threading.Lock）
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"""
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def __init__(
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self,
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max_size: int = 1000, # 默认最多缓存 1000 个 Agent
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default_ttl: int = 180, # 默认 3 分钟过期
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auto_renew: bool = True # 访问时自动延长过期时间
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):
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"""
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初始化内存缓存管理器
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Args:
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max_size: 最大缓存项数
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default_ttl: 默认过期时间（秒）
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auto_renew: 是否在访问时自动延长过期时间
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"""
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# 使用 TTLCache 实现带过期时间的缓存
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self.cache = cachetools.TTLCache(
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maxsize=max_size,
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ttl=default_ttl,
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timer=time.monotonic
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)
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# 用于存储每个键的过期时间信息（支持自动续期）
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self._expire_times: Dict[str, float] = {}
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# 用于存储创建时间
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self._create_times: Dict[str, float] = {}
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# 锁，确保线程安全
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self._lock = threading.RLock()
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self.default_ttl = default_ttl
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self.auto_renew = auto_renew
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self.max_size = max_size
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# 统计信息
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self._hits = 0
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self._misses = 0
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self._sets = 0
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self._evictions = 0
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logger.info(f"AgentMemoryCacheManager initialized with max_size: {max_size}, "
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f"default_ttl: {default_ttl}s, auto_renew: {auto_renew}")
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def get(self, cache_key: str) -> Optional[Any]:
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"""
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获取缓存的 Agent
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Args:
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cache_key: 缓存键
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Returns:
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Agent 对象或 None
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"""
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with self._lock:
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current_time = time.monotonic()
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# 首先检查是否过期
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if cache_key in self._expire_times:
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if current_time > self._expire_times[cache_key]:
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# 已过期，清理
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self._remove_expired(cache_key)
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self._misses += 1
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logger.debug(f"Cache miss (expired) for key: {cache_key}")
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return None
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# 尝试从缓存获取
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try:
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value = self.cache[cache_key]
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# 如果启用自动续期
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if self.auto_renew:
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self._expire_times[cache_key] = current_time + self.default_ttl
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logger.debug(f"Cache hit and renewed for key: {cache_key}")
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else:
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logger.debug(f"Cache hit for key: {cache_key}")
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self._hits += 1
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return value
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except KeyError:
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self._misses += 1
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logger.debug(f"Cache miss for key: {cache_key}")
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return None
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def set(self, cache_key: str, agent: Any, ttl: Optional[int] = None) -> bool:
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"""
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缓存 Agent 对象
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Args:
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cache_key: 缓存键
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agent: 要缓存的 Agent 对象
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ttl: 过期时间（秒），如果为 None 则使用默认值
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Returns:
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是否成功设置缓存
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"""
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with self._lock:
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try:
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if ttl is None:
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ttl = self.default_ttl
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current_time = time.monotonic()
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expire_time = current_time + ttl
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# 检查是否需要驱逐项
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evicted_key = None
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if cache_key not in self.cache and len(self.cache) >= self.max_size:
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# cachetools 的 TTLCache 会自动驱逐，但我们要记录
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# 先获取可能被驱逐的键
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oldest_key = next(iter(self.cache)) if self.cache else None
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if oldest_key:
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evicted_key = oldest_key
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# 设置缓存
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self.cache[cache_key] = agent
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self._expire_times[cache_key] = expire_time
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self._create_times[cache_key] = current_time
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# 清理被驱逐的项的元数据
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if evicted_key and evicted_key != cache_key:
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self._cleanup_metadata(evicted_key)
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self._evictions += 1
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logger.debug(f"Evicted cache key: {evicted_key}")
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self._sets += 1
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logger.info(f"Cached agent for key: {cache_key}, ttl: {ttl}s")
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return True
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except Exception as e:
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logger.error(f"Error setting cache for key {cache_key}: {e}")
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return False
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def delete(self, cache_key: str) -> bool:
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"""
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删除特定的缓存项
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Args:
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cache_key: 缓存键
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Returns:
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是否成功删除
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"""
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with self._lock:
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try:
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# 从缓存中删除
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deleted = cache_key in self.cache
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if deleted:
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del self.cache[cache_key]
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# 清理元数据
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self._cleanup_metadata(cache_key)
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if deleted:
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logger.info(f"Deleted cache for key: {cache_key}")
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else:
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logger.warning(f"Cache key not found for deletion: {cache_key}")
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return deleted
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except Exception as e:
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logger.error(f"Error deleting cache for key {cache_key}: {e}")
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return False
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def _remove_expired(self, cache_key: str):
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"""移除过期的缓存项"""
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if cache_key in self.cache:
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del self.cache[cache_key]
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self._cleanup_metadata(cache_key)
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def _cleanup_metadata(self, cache_key: str):
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"""清理指定键的元数据"""
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self._expire_times.pop(cache_key, None)
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self._create_times.pop(cache_key, None)
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def clear_all(self) -> bool:
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"""
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清空所有缓存
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Returns:
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是否成功清空
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"""
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with self._lock:
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try:
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count = len(self.cache)
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self.cache.clear()
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self._expire_times.clear()
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self._create_times.clear()
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# 重置统计信息
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self._hits = 0
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self._misses = 0
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self._sets = 0
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self._evictions = 0
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logger.info(f"Cleared all cache entries, total: {count}")
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return True
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except Exception as e:
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logger.error(f"Error clearing all cache: {e}")
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return False
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def get_stats(self) -> Dict[str, Any]:
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"""
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获取缓存统计信息
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Returns:
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包含统计信息的字典
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"""
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with self._lock:
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total_requests = self._hits + self._misses
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hit_rate = (self._hits / total_requests * 100) if total_requests > 0 else 0
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return {
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"type": "memory",
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"total_items": len(self.cache),
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"max_size": self.max_size,
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"default_ttl": self.default_ttl,
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"auto_renew": self.auto_renew,
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"hits": self._hits,
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"misses": self._misses,
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"hit_rate_percent": round(hit_rate, 2),
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"sets": self._sets,
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"evictions": self._evictions,
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"memory_usage_mb": round(self._estimate_memory_usage() / 1024 / 1024, 2)
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}
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def _estimate_memory_usage(self) -> int:
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"""估算内存使用量（字节）"""
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# 这是一个粗略的估算
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import sys
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total_size = 0
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# 估算缓存项的大小
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for key, value in self.cache.items():
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total_size += sys.getsizeof(key)
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total_size += sys.getsizeof(value)
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# 估算元数据的大小
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total_size += sys.getsizeof(self._expire_times)
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total_size += sys.getsizeof(self._create_times)
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return total_size
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def cleanup_old_entries(self, max_age_seconds: int = 3600) -> int:
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"""
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清理超过指定时间的所有缓存项
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Args:
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max_age_seconds: 最大存在时间（秒）
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Returns:
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清理的缓存项数量
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"""
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with self._lock:
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current_time = time.monotonic()
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keys_to_delete = []
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# 查找超过最大时间的项
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for cache_key, create_time in self._create_times.items():
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age_seconds = current_time - create_time
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if age_seconds > max_age_seconds:
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keys_to_delete.append(cache_key)
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# 删除旧项
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deleted_count = 0
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for key in keys_to_delete:
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if self.delete(key):
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deleted_count += 1
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logger.info(f"Cleaned up {deleted_count} old cache entries older than {max_age_seconds}s")
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return deleted_count
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def get_keys(self) -> list:
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"""
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获取所有缓存键
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Returns:
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缓存键列表
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"""
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with self._lock:
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return list(self.cache.keys())
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def __len__(self) -> int:
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"""返回缓存中的项数"""
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return len(self.cache)
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# 全局缓存管理器实例
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_global_cache_manager: Optional[AgentMemoryCacheManager] = None
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def get_memory_cache_manager() -> AgentMemoryCacheManager:
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"""
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获取全局内存缓存管理器实例（单例模式）
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Returns:
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AgentMemoryCacheManager 实例
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"""
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global _global_cache_manager
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if _global_cache_manager is None:
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# 从环境变量或使用默认值
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max_size = int(os.getenv("AGENT_CACHE_MAX_SIZE", "20"))
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default_ttl = int(os.getenv("AGENT_CACHE_TTL", "180"))
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auto_renew = os.getenv("AGENT_CACHE_AUTO_RENEW", "true").lower() == "true"
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_global_cache_manager = AgentMemoryCacheManager(
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max_size=max_size,
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default_ttl=default_ttl,
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auto_renew=auto_renew
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)
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return _global_cache_manager |