feat: 交易日9:31清空全部缓存，保证开盘后数据全新

- services/cache.py 新增 clear_all() 清空整个 cache 表
- daily_collector.py 新增 cache_cleanup_loop() 后台循环：精确 sleep 到最近一个
  工作日 9:31 清空缓存，跳过周末，出错1分钟重试
- main.py lifespan 启动清理任务，与采集任务一同优雅退出

与既有"非交易时段 TTL 截止到下次开盘前"的惰性过期形成双保险

Co-Authored-By: Claude <noreply@anthropic.com>

backend/main.py

@@ -8,7 +8,7 @@ from dotenv import load_dotenv
 
 from database import init_db
 from routes import stock, collections, shares, sectors, themes, core_stocks
-from services.daily_collector import collector_loop
+from services.daily_collector import collector_loop, cache_cleanup_loop
 
 load_dotenv()
 
@@ -17,14 +17,17 @@ load_dotenv()
 async def lifespan(app: FastAPI):
     init_db()
     collector_task = asyncio.create_task(collector_loop())
+    cache_cleanup_task = asyncio.create_task(cache_cleanup_loop())
     try:
         yield
     finally:
-        collector_task.cancel()
-        try:
-            await collector_task
-        except asyncio.CancelledError:
-            pass
+        for t in (collector_task, cache_cleanup_task):
+            t.cancel()
+        for t in (collector_task, cache_cleanup_task):
+            try:
+                await t
+            except asyncio.CancelledError:
+                pass
 
 
 app = FastAPI(title="AUV API", version="1.0.0", lifespan=lifespan)

backend/services/cache.py

@@ -56,3 +56,13 @@ def clean_expired():
         conn.commit()
     finally:
         conn.close()
+
+
+def clear_all():
+    """清空全部缓存（每日开盘后 9:31 调用，保证当日数据全新）"""
+    conn = get_connection()
+    try:
+        conn.execute("DELETE FROM cache")
+        conn.commit()
+    finally:
+        conn.close()

backend/services/daily_collector.py

@@ -9,6 +9,7 @@ from datetime import datetime, time as dtime, timezone, timedelta
 from typing import Optional
 
 from database import get_connection
+from services.cache import clear_all
 from services.themes import fetch_theme_list, _build_theme_graph
 
 _CST = timezone(timedelta(hours=8))
@@ -22,6 +23,9 @@ HOTMAP_TOP_N = 50           # 热点穿透采样题材数：涨幅榜+热度榜
 HOTMAP_CORE_LIMIT = 100     # 热点穿透核心股前100（按覆盖题材数降序）
 CORE_COVER_THRESHOLD = 2    # 热点穿透核心股门槛：覆盖题材数 ≥2
 
+# 每日缓存清理：交易日 9:31 清空全部缓存，保证开盘后数据全新
+CLEANUP_TIME = dtime(9, 31)
+
 
 def _is_trading_day(d: datetime) -> bool:
     """仅按工作日判断：周一至周五视为交易日，不处理法定节假日"""
@@ -185,3 +189,45 @@ async def collector_loop(stop: Optional[asyncio.Event] = None) -> None:
         if stop is not None and stop.is_set():
             break
         await asyncio.sleep(CHECK_INTERVAL_SECONDS)
+
+
+def _next_cleanup_dt(now: datetime) -> datetime:
+    """计算下一个缓存清理时刻：最近一个工作日 9:31（今天已过则取下一个工作日）"""
+    for days in range(0, 8):
+        d = (now + timedelta(days=days)).date()
+        if d.weekday() >= 5:  # 跳过周末
+            continue
+        dt = datetime(d.year, d.month, d.day, CLEANUP_TIME.hour, CLEANUP_TIME.minute, tzinfo=_CST)
+        if dt > now:
+            return dt
+    return now + timedelta(days=1)  # 兜底：理论不可达
+
+
+async def cache_cleanup_loop(stop: Optional[asyncio.Event] = None) -> None:
+    """后台循环：每个交易日 9:31 清空全部缓存，保证开盘后读到全新数据
+
+    到点前精确 sleep 至 9:31；若进程在 9:31 后启动，则等下一个交易日。
+    """
+    while True:
+        try:
+            now = datetime.now(_CST)
+            next_dt = _next_cleanup_dt(now)
+            delay = max(0, int((next_dt - now).total_seconds()))
+            if stop is not None:
+                try:
+                    await asyncio.wait_for(stop.wait(), timeout=delay)
+                except asyncio.TimeoutError:
+                    pass  # 到点
+                if stop.is_set():
+                    break
+            else:
+                await asyncio.sleep(delay)
+
+            clear_all()
+            print(f"[cache-cleanup] 已清空全部缓存: {datetime.now(_CST).strftime('%Y-%m-%d %H:%M:%S')}")
+        except asyncio.CancelledError:
+            raise
+        except Exception:
+            print("[cache-cleanup] 清理异常：")
+            traceback.print_exc()
+            await asyncio.sleep(60)  # 出错 1 分钟后再试