Files
MoviePilot/app/runtime/extensions/plugin/admission.py
T

113 lines
3.8 KiB
Python

"""插件宿主可变事务的停机准入。"""
from __future__ import annotations
import threading
from collections.abc import Iterator
from contextlib import contextmanager
from contextvars import ContextVar
from dataclasses import dataclass
from app.schemas.exception import PluginMutationRejectedError
@dataclass(slots=True)
class _MutationContext:
"""记录一个可跨协程和受控线程传播的事务上下文。"""
admission: "PluginMutationAdmission"
holders: int = 0
open: bool = True
class PluginMutationAdmission:
"""在停机封口与插件可变事务之间维护真实 owner 计数。"""
def __init__(self) -> None:
"""初始化开放准入、活动 owner 计数和事务上下文。"""
self._condition = threading.Condition()
self._accepting = True
self._active_count = 0
self._current_context: ContextVar[_MutationContext | None] = ContextVar(
"plugin_mutation_context",
default=None,
)
@property
def active_count(self) -> int:
"""返回尚未退出的 lease 数量,用于停机诊断和严格卸载判断。"""
with self._condition:
return self._active_count
@property
def accepting(self) -> bool:
"""返回当前生命周期是否仍接纳新的根事务。"""
with self._condition:
return self._accepting
def is_held(self) -> bool:
"""判断当前执行上下文是否持有仍有效的本 admission lease。"""
context = self._current_context.get()
with self._condition:
return bool(
context
and context.admission is self
and context.open
and context.holders > 0
)
@contextmanager
def hold(self, operation: str) -> Iterator[None]:
"""取得可变事务 lease;封口后仅允许已获准事务的嵌套调用。"""
context = self._current_context.get()
context_token = None
acquired = False
try:
with self._condition:
nested = bool(
context
and context.admission is self
and context.open
and context.holders > 0
)
if not self._accepting and not nested:
raise PluginMutationRejectedError(operation)
if not nested:
context = _MutationContext(admission=self)
context_token = self._current_context.set(context)
assert context is not None
self._active_count += 1
context.holders += 1
acquired = True
yield
finally:
if acquired:
with self._condition:
self._active_count -= 1
context.holders -= 1
if context.holders == 0:
context.open = False
self._condition.notify_all()
if context_token is not None:
self._current_context.reset(context_token)
def seal(self) -> int:
"""原子停止接纳根事务,并返回封口瞬间的活动 lease 数量。"""
with self._condition:
self._accepting = False
return self._active_count
def wait_until_idle(self) -> None:
"""自然等待全部已获准 lease 退出,不取消或遗失其 owner。"""
with self._condition:
while self._active_count:
self._condition.wait()
def reopen(self) -> bool:
"""仅在没有遗留 lease 时为新的应用生命周期重新开放准入。"""
with self._condition:
if self._active_count:
return False
self._accepting = True
return True