Async Retry with Exponential Backoff

import asyncio
import random
from typing import Awaitable, Callable, TypeVar

T = TypeVar("T")

async def aretry(
    fn: Callable[[], Awaitable[T]],
    attempts: int = 5,
    base: float = 0.2,
    should_retry: Callable[[BaseException], bool] = lambda _: True,
) -> T:
    last: BaseException | None = None
    for i in range(1, attempts + 1):
        try:
            return await fn()
        except BaseException as e:
            last = e
            if i == attempts or not should_retry(e):
                raise
            delay = base * (2 ** (i - 1))
            await asyncio.sleep(delay + random.random() * delay)
    raise RuntimeError("unreachable") from last

async def flaky():
    if random.random() < 0.8:
        raise ConnectionError("oops")
    return "ok"

print(asyncio.run(aretry(flaky, attempts=10)))