Hi there, I'm trying to achieve pretty standard exponential back-off with capped max delay kinda th...

# arrow

[Ruslan Sierov]

Hi there,

I'm trying to achieve pretty standard exponential back-off with capped max delay kinda thing using arrow.resilience. So far I have this code that passes my tests, but the delay in doWhile doesn't seem right to me. I'm sure I'm missing some idiomatic way to achieve exactly that with arrow's operators.

suspend fun <L, R> withExponentialRetries(
    until: (Either<L, R>) -> Boolean = { it.isRight() },
    retries: Long = 4,
    delay: Duration = 500.milliseconds,
    maxDelayCap: Duration = Duration.INFINITE,
    block: suspend () -> Either<L, R>,
): Either<L, R> = Schedule.exponential<Either<L, R>>(base = delay)
    .doWhile { _, duration ->
        val proceedExponentially = duration < maxDelayCap
        // this delay is needed before switching to spaced
        // scheduler so we don't immediately call [block]
        if (!proceedExponentially) delay(maxDelayCap)
        proceedExponentially
    }
    .andThen(Schedule.spaced(maxDelayCap))
    .and(Schedule.recurs(retries))
    .doUntil { yielded, _ -> until(yielded) }
    .zipRight(Schedule.identity())
    .repeat(block)

and my tests are