from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker
from app.config import settings

# 配置连接池参数以避免连接丢失问题
engine = create_engine(
    settings.DATABASE_URL,
    pool_pre_ping=True,  # 连接前测试连接是否有效
    pool_recycle=300,    # 每5分钟重新创建连接
    pool_size=10,        # 连接池大小
    max_overflow=20,     # 最大溢出连接数
    echo=False           # 关闭SQL日志（生产环境）
)
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)

Base = declarative_base()

def get_db():
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()