63 lines
1.9 KiB
Python
63 lines
1.9 KiB
Python
from abc import ABC, abstractmethod
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from datetime import timedelta
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from types import TracebackType
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from typing import Any, Protocol, Self, Union, runtime_checkable
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CACHE_EXPIRE_TIME = timedelta(weeks=4)
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MAX_CACHE_ITEM = 1000
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@runtime_checkable
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class AsyncLock(Protocol):
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"""Protocol for async context manager locks (compatible with redis.asyncio.lock.Lock and NoopLock)."""
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async def __aenter__(self) -> Self: ...
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async def __aexit__(
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self,
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exc_type: type[BaseException] | None,
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exc_val: BaseException | None,
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exc_tb: TracebackType | None,
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) -> None: ...
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class NoopLock:
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"""
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A no-op lock implementation for use when distributed locking is not available.
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Acts as an async context manager that does nothing - suitable for OSS/local deployments.
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"""
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def __init__(self, lock_name: str, blocking_timeout: int = 5, timeout: int = 10) -> None:
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self.lock_name = lock_name
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self.blocking_timeout = blocking_timeout
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self.timeout = timeout
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async def __aenter__(self) -> "NoopLock":
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return self
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async def __aexit__(
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self,
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exc_type: type[BaseException] | None,
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exc_val: BaseException | None,
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exc_tb: TracebackType | None,
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) -> None:
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pass
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class BaseCache(ABC):
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@abstractmethod
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async def set(self, key: str, value: Any, ex: Union[int, timedelta, None] = CACHE_EXPIRE_TIME) -> None:
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pass
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@abstractmethod
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async def get(self, key: str) -> Any:
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pass
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def get_lock(self, lock_name: str, blocking_timeout: int = 5, timeout: int = 10) -> AsyncLock:
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"""
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Get a distributed lock for the given name.
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Default implementation returns a no-op lock for OSS deployments.
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Cloud implementations should override this to use Redis locks.
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"""
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return NoopLock(lock_name, blocking_timeout, timeout)
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