Generic circuit breaker backend wrapper about sttp

[adamw]

I'm not really sure if we should do this task, or not. There's resilience4j, but there's also akka's circuit breaker and monix's one. Maybe a resilience4j integration module makes sense: I don't know the library, and hence I don't know how hard it is to integrate with it.

But in Akka and Monix's case, you wrap any => Future[T]/Task[T]. In our case this might be the result of request.send(). I think there's nothing specific in making http calls that would require special integration. So while having an out-of-the box circuit breakers etc. in sttp would be great, I fear this might be too specialised and generally a waste of code.

Btw. - same considerations apply to a retry backend / rate-limiting backend etc.

Either way we go, we should document how to create a circuit breaker / rate-limiter etc. :) And maybe the right way to approach this is to create resilience4s or extend monix-catnap (which already has the circuit breaker)?

[ghostbuster91]

Since hystrix is no longer actively developed I think that we should use resilience4j-circuitbreaker from https://github.com/resilience4j/resilience4j. There are integrators for retrofit and feign so we can look how they were made.

[adamw]

Given that there's quite a lot of circuit breakers out there, and that integration with them is mostly trivial, we decided to document how to do that, instead of providing multiple integrations. See: https://sttp.readthedocs.io/en/latest/backends/custom.html#example-backend-with-circuit-breaker