Retrying the retry design by Michał Płachta | Scalar Conference 2025 скачать в хорошем качестве

Retrying the retry design by Michał Płachta | Scalar Conference 2025

Retrying failed side-effectful actions is the bread & butter for all programmers. Whether you use Python, Ruby, Java, or Scala, you’ll use the same retry strategies: usually some backoff and randomness. In functional Scala, we use the powers of referential transparency (RT). If your API call is described as an IO value, you just create a new IO value that adds the retry logic of your choice. Easy, right? Things get nasty very quickly when an API or a DB you call has more constraints. Imagine a retry strategy that starts with a 5ms delay and uses a Fibonacci backoff, but each individual delay is capped at 5s and you always do a final retry after the timeout passes. How would you make sure it’s working correctly? Is referential transparency helpful? In this talk, Michał will discuss why it's hard to use the power of RT to test side-effect-heavy apps. The main problem is that our APIs and library APIs don't use the full power of RT: they focus too much on side effects and not the value representation of these side effects. This in turn makes testing such apps very difficult. He will present some alternative ideas for a better, more RT-friendly design for retries and many more side-effectful APIs. http://scalar-conf.com/ Scalar Conference 2025 powered by SoftwareMill #scalarconf