mirror of
https://github.com/jxxghp/MoviePilot.git
synced 2026-10-29 11:27:43 +08:00
141 lines
4.3 KiB
Python
141 lines
4.3 KiB
Python
"""
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插件宿主可变事务的停机准入。
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"""
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from __future__ import annotations
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import threading
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from collections.abc import Iterator
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from contextlib import contextmanager
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from contextvars import ContextVar
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from dataclasses import dataclass
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from app.schemas.exception import PluginMutationRejectedError
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@dataclass(slots=True)
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class _MutationContext:
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"""
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记录一个可跨协程和受控线程传播的事务上下文。
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:param admission: 负责本次变更事务准入的控制器
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:param holders: 持有该上下文的调用数，初始为 0
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:param open: 上下文是否仍接受后续持有者，初始为 True
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"""
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admission: "PluginMutationAdmission"
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holders: int = 0
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open: bool = True
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class PluginMutationAdmission:
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"""
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在停机封口与插件可变事务之间维护真实 owner 计数。
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"""
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def __init__(self) -> None:
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"""
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初始化开放准入、活动 owner 计数和事务上下文。
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"""
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self._condition = threading.Condition()
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self._accepting = True
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self._active_count = 0
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self._current_context: ContextVar[_MutationContext | None] = ContextVar(
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"plugin_mutation_context",
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default=None,
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)
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@property
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def active_count(self) -> int:
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"""
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返回尚未退出的 lease 数量，用于停机诊断和严格卸载判断。
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"""
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with self._condition:
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return self._active_count
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@property
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def accepting(self) -> bool:
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"""
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返回当前生命周期是否仍接纳新的根事务。
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"""
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with self._condition:
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return self._accepting
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def is_held(self) -> bool:
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"""
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判断当前执行上下文是否持有仍有效的本 admission lease。
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"""
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context = self._current_context.get()
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with self._condition:
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return bool(
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context
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and context.admission is self
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and context.open
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and context.holders > 0
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)
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@contextmanager
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def hold(self, operation: str) -> Iterator[None]:
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"""
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取得可变事务 lease；封口后仅允许已获准事务的嵌套调用。
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"""
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context = self._current_context.get()
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context_token = None
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acquired = False
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try:
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with self._condition:
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nested = bool(
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context
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and context.admission is self
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and context.open
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and context.holders > 0
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)
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if not self._accepting and not nested:
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raise PluginMutationRejectedError(operation)
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if not nested:
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context = _MutationContext(admission=self)
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context_token = self._current_context.set(context)
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assert context is not None
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self._active_count += 1
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context.holders += 1
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acquired = True
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yield
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finally:
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if acquired:
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# acquired 只会在上下文已验证且 owner 计数增加后置为 True。
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assert context is not None
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with self._condition:
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self._active_count -= 1
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context.holders -= 1
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if context.holders == 0:
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context.open = False
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self._condition.notify_all()
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if context_token is not None:
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self._current_context.reset(context_token)
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def seal(self) -> int:
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"""
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原子停止接纳根事务，并返回封口瞬间的活动 lease 数量。
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"""
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with self._condition:
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self._accepting = False
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return self._active_count
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def wait_until_idle(self) -> None:
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"""
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自然等待全部已获准 lease 退出，不取消或遗失其 owner。
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"""
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with self._condition:
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while self._active_count:
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self._condition.wait()
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def reopen(self) -> bool:
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"""
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仅在没有遗留 lease 时为新的应用生命周期重新开放准入。
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"""
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with self._condition:
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if self._active_count:
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return False
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self._accepting = True
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return True
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