后端模块拆分

src/shared/database/database.py

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+# shared/database/database.py
+import sys
+import os
+from pathlib import Path
+
+from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession, async_sessionmaker
+from sqlalchemy import text
+from sqlalchemy.orm import sessionmaker
+from shared.config.settings import settings
+import asyncio
+from contextlib import asynccontextmanager
+from shared.utils.logger import get_logger
+
+logger = get_logger(__name__)
+
+class DatabaseManager:
+    """数据库管理器"""
+    
+    def __init__(self):
+        self.engine = None
+        self.async_session = None
+        self.is_connected = False
+    
+    async def connect(self):
+        """连接数据库"""
+        if not settings.DATABASE_URL:
+            logger.warning("未配置数据库连接，跳过数据库初始化")
+            self.is_connected = False
+            return
+            
+        try:
+            # 创建异步引擎
+            self.engine = create_async_engine(
+                settings.DATABASE_URL,
+                echo=settings.DEBUG,
+                pool_size=20,
+                max_overflow=30,
+                pool_recycle=3600
+            )
+            
+            # 创建异步会话工厂
+            self.async_session = async_sessionmaker(
+                self.engine,
+                class_=AsyncSession,
+                expire_on_commit=False
+            )
+            
+            # 测试连接
+            async with self.engine.begin() as conn:
+                await conn.execute(text("SELECT 1"))
+            
+            self.is_connected = True
+            logger.info("数据库连接成功")
+            
+        except Exception as e:
+            logger.error(f"数据库连接失败: {e}")
+            self.is_connected = False
+            raise
+    
+    async def disconnect(self):
+        """断开数据库连接"""
+        if self.engine:
+            await self.engine.dispose()
+            self.is_connected = False
+            logger.info("数据库连接已断开")
+    
+    @asynccontextmanager
+    async def session(self):
+        """获取数据库会话的异步上下文管理器"""
+        if not self.is_connected:
+            await self.connect()
+        
+        session = self.async_session()
+        try:
+            yield session
+        finally:
+            await session.close()
+    
+    async def get_session(self) -> AsyncSession:
+        """获取数据库会话"""
+        if not self.is_connected:
+            await self.connect()
+        
+        return self.async_session()
+    
+    async def create_tables(self):
+        """创建数据库表"""
+        from models.database import Base
+        
+        try:
+            async with self.engine.begin() as conn:
+                await conn.run_sync(Base.metadata.create_all)
+            logger.info("数据库表创建成功")
+        except Exception as e:
+            logger.error(f"数据库表创建失败: {e}")
+            raise
+
+# 全局数据库管理器实例
+db_manager = DatabaseManager()
+
+# 数据库依赖注入
+async def get_db_session():
+    """获取数据库会话的依赖函数"""
+    session = await db_manager.get_session()
+    try:
+        yield session
+    finally:
+        await session.close()