49 lines
1.6 KiB
Python
49 lines
1.6 KiB
Python
"""同账套任务串行锁；独立持有 MySQL 连接，跨分页 commit 仍保持有效。"""
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import hashlib
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from contextlib import contextmanager
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from sqlalchemy import text
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from sqlalchemy.orm import Session
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class TPlusBusyError(RuntimeError):
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"""已有任务持有执行锁。"""
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def lock_name(session: Session) -> str:
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"""生成不含地址、账号或密码的固定长度锁名。"""
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database = session.get_bind().url.database or "default"
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return "ys:tplus:read:" + hashlib.sha256(database.encode()).hexdigest()[:24]
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@contextmanager
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def sync_lock(session: Session):
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"""只在取得锁后执行；释放失败时使连接失效，防止带锁回池。"""
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engine = session.get_bind()
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if engine.dialect.name != "mysql":
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raise RuntimeError("T+ 执行协调需要 MySQL 命名锁")
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connection = engine.connect()
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acquired = False
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try:
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acquired = (
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connection.execute(
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text("SELECT GET_LOCK(:name, 0)"), {"name": lock_name(session)}
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).scalar_one()
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== 1
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)
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if not acquired:
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raise TPlusBusyError("已有 T+ 任务正在执行，请稍后重试")
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yield
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finally:
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if acquired:
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try:
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released = connection.execute(
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text("SELECT RELEASE_LOCK(:name)"), {"name": lock_name(session)}
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).scalar_one()
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if released != 1:
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connection.invalidate()
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except Exception:
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connection.invalidate()
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connection.close()
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