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