from asyncio import sleep
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from typing import TYPE_CHECKING, Any, Awaitable, Callable, Tuple, Type, TypeVar
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from redis.exceptions import ConnectionError, RedisError, TimeoutError
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from redis.retry import AbstractRetry
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T = TypeVar("T")
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if TYPE_CHECKING:
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from redis.backoff import AbstractBackoff
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class Retry(AbstractRetry[RedisError]):
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__hash__ = AbstractRetry.__hash__
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def __init__(
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self,
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backoff: "AbstractBackoff",
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retries: int,
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supported_errors: Tuple[Type[RedisError], ...] = (
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ConnectionError,
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TimeoutError,
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),
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):
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super().__init__(backoff, retries, supported_errors)
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def __eq__(self, other: Any) -> bool:
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if not isinstance(other, Retry):
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return NotImplemented
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return (
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self._backoff == other._backoff
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and self._retries == other._retries
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and set(self._supported_errors) == set(other._supported_errors)
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)
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async def call_with_retry(
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self, do: Callable[[], Awaitable[T]], fail: Callable[[RedisError], Any]
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) -> T:
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"""
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Execute an operation that might fail and returns its result, or
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raise the exception that was thrown depending on the `Backoff` object.
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`do`: the operation to call. Expects no argument.
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`fail`: the failure handler, expects the last error that was thrown
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"""
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self._backoff.reset()
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failures = 0
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while True:
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try:
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return await do()
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except self._supported_errors as error:
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failures += 1
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await fail(error)
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if self._retries >= 0 and failures > self._retries:
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raise error
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backoff = self._backoff.compute(failures)
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if backoff > 0:
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await sleep(backoff)
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