50 lines
1.8 KiB
Python
50 lines
1.8 KiB
Python
"""SQLAlchemy 引擎工厂（B7 · 开发计划挂账⑥）。
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按库名缓存单例 Engine：deps / risk / simulate 路由每请求实例化 Repository 时
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复用同一连接池，不再每次 create_engine（B6 复审 P3：实例化点泄漏）；应用
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shutdown 经 dispose_engines 统一释放（B7 评审 P1-1：显式 Engine.dispose()，
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不依赖 GC 兜底）。测试直传 engine= 参数的用法不受影响；
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monkeypatch settings 后须先 dispose_engines() 清缓存。
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"""
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from __future__ import annotations
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import threading
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from sqlalchemy import create_engine
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from sqlalchemy.engine import Engine
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from app.config.settings import settings
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_engines: dict[str, Engine] = {}
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_engines_lock = threading.Lock()
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def get_engine(database: str) -> Engine:
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"""取指定库的单例 Engine（进程内共享连接池）。"""
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with _engines_lock:
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engine = _engines.get(database)
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if engine is None:
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pwd = settings.mysql_password
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auth = f"{settings.mysql_user}:{pwd}" if pwd else settings.mysql_user
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url = (
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f"mysql+pymysql://{auth}@{settings.mysql_host}:{settings.mysql_port}"
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f"/{database}?charset=utf8mb4"
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)
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engine = create_engine(url, pool_pre_ping=True)
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_engines[database] = engine
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return engine
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def dispose_engines() -> None:
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"""释放全部缓存 Engine（lifespan shutdown / 测试隔离）。
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逐个 Engine.dispose() 关闭连接池空闲连接后清空缓存；调用方仍持有的
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checked-out 连接不受影响，归还时由旧池关闭。dispose 后再 get_engine
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按当前 settings 重建（测试 monkeypatch 配置依赖此语义）。
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"""
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with _engines_lock:
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for engine in _engines.values():
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engine.dispose()
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_engines.clear()
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