Uni using withBackoff and until

[manofthepeace]

I have a case where I am trying a http call and I want to retry with a delay until a predicate. So I am using something a little like this;

myhttpService.doCall().onFailure().retry().withBackoff(min,max).until(myPredicate)

In short I want to wait a certain amount of time before retrying the http call, until a predicate which decide it does not make sense anymore to retry. The above gives me the following error;

java.lang.IllegalArgumentException: Invalid retry configuration, `when` cannot be used with a back-off configuration

I find the error above not exactly clear since I am not using when, but I understand until eventually calls when. But I also am not sure to understand that limitation. Is there a way I can achieve the above? i.e. retry a http call every minute or so.

Thanks,
Alex

[jponge]

Indeed you cannot mix a backoff retry with a custom predicate.

One thing you could try is to have a predicate that both evaluates wether to retry or not, and blocks so you can have a hold on the timing aspect. That being said this won't play well with an event-loop, so you'd need to offset that blocking code to an executor with emitOn/subscribeOn.

[manofthepeace]

Thank you for your reply. Ultimately I went with something like this, which seem to be eventloop friedly. Does that seem right to you?

myhttpService.doCall()
.onFailure(MyCustomException.class).call(t->Uni.createFrom().nullItem().delayIt().by(SomeDuration))
.onFailure(MyCustomException.class).retry().until(myPredicate);

[jponge]

That's actually quite smart 👍