109 lines
3.4 KiB
Python
109 lines
3.4 KiB
Python
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"""
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会话记忆管理器
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管理每个用户的对话上下文，支持多轮对话状态机。
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内存缓存，10 分钟 TTL 自动清除。
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"""
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import time
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from typing import Dict, List, Optional
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from app.utils.logger import logger
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SESSION_TTL = 600 # 10 分钟
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class UserSession:
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"""单个用户的会话上下文"""
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def __init__(self, user_id: str):
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self.user_id = user_id
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self.state = "idle" # idle / waiting_location / waiting_confirm / waiting_close_photo
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self.pending_image_url = "" # 暂存的图片 COS key
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self.pending_analysis = "" # VLM 分析结果描述
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self.pending_alarm_type = "" # VLM 识别的告警类型
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self.pending_order_id = "" # 待结单的工单 ID
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self.pending_alarm_id = "" # 关联的告警 ID
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self.history: List[Dict] = [] # 对话历史 [{"role": "user/assistant", "content": ...}]
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self.updated_at = time.time()
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def is_expired(self) -> bool:
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return time.time() - self.updated_at > SESSION_TTL
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def touch(self):
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self.updated_at = time.time()
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def reset(self):
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"""重置状态机（保留 history）"""
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self.state = "idle"
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self.pending_image_url = ""
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self.pending_analysis = ""
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self.pending_alarm_type = ""
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self.pending_order_id = ""
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self.pending_alarm_id = ""
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def add_history(self, role: str, content):
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"""添加对话记录，content 可以是 str 或 list（多模态）"""
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self.history.append({"role": role, "content": content})
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# 保留最近 10 轮（20 条消息）
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if len(self.history) > 20:
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self.history = self.history[-20:]
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self.touch()
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def get_history_for_vlm(self) -> List[Dict]:
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"""获取用于 VLM 调用的 history（过滤掉过大的图片内容）"""
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return self.history.copy()
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class SessionManager:
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"""全局会话管理器（单例）"""
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def __init__(self):
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self._sessions: Dict[str, UserSession] = {}
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self._last_cleanup = time.time()
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def get(self, user_id: str) -> UserSession:
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"""获取或创建用户会话"""
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# 定期清理过期会话（每 5 分钟）
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if time.time() - self._last_cleanup > 300:
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self._cleanup_expired()
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session = self._sessions.get(user_id)
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if session and not session.is_expired():
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session.touch()
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return session
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# 过期或不存在，创建新会话
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session = UserSession(user_id)
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self._sessions[user_id] = session
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return session
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def clear(self, user_id: str):
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"""清除用户会话"""
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if user_id in self._sessions:
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self._sessions[user_id].reset()
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self._sessions[user_id].history.clear()
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def _cleanup_expired(self):
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"""清理过期会话"""
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expired = [uid for uid, s in self._sessions.items() if s.is_expired()]
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for uid in expired:
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del self._sessions[uid]
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if expired:
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logger.debug(f"清理 {len(expired)} 个过期会话")
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self._last_cleanup = time.time()
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@property
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def active_count(self) -> int:
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return sum(1 for s in self._sessions.values() if not s.is_expired())
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_session_manager: Optional[SessionManager] = None
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def get_session_manager() -> SessionManager:
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global _session_manager
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if _session_manager is None:
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_session_manager = SessionManager()
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return _session_manager
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