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# arrow
j
Jörg Winter
10/16/2023, 5:48 AMHi,
with Arrow 1.2.1, would this be the most idiomatic way to use high-level concurrency (parZip) and not short-circuiting (by using Either results) and finally, if all results are Either.right, making the insert in some database (in this case) ?
Logging/Aggregating also goes in a separate call to "onLeft", as I think there is no handler for it in "zipOrAccumulate" (?)
Copy code
suspend fun collectData() {
parZip(
{ catch { fetchFromHttp1() } },
{ catch { fetchFromHttp2() } },
{ catch { fetchFromHttp3() } }
) { result1, result2, result3 ->
val result = zipOrAccumulate(result1, result2, result3) { r1, r2, r3 ->
dbRepository.save(Entity(r1, r2, r3))
}
result.onLeft {
log.error(it.map { it.message }.joinToString("\n", "\n"))
}
}
}s
simon.vergauwen
10/16/2023, 6:00 AMHey @Jörg Winter,
There is also
parZipOrAccumulate Copy code
suspend fun collectData() {
parZipOrAccumulate(
{ catch { fetchFromHttp1() }.bind() },
{ catch { fetchFromHttp2() }.bind() },
{ catch { fetchFromHttp3() }.bind() }
) { r1, r2, r3 ->
dbRepository.save(Entity(r1, r2, r3))
.onLeft {
log.error(it.map { it.message }.joinToString("\n", "\n"))
}
}
}j
Jörg Winter
10/16/2023, 6:04 AMI am using 1.2.1 but I can not use that construct, seems to require transform fn as first param, and bind is deprecated (?)
a
Alejandro Serrano.Mena
10/16/2023, 7:00 AMoh, weird, bind should never be deprecated (unless used in Effect)
j
Jörg Winter
10/16/2023, 7:06 AMparZipOrAccumulate is not even suggested by Intellij in my code, so I am not sure if I am in the necessary context maybe…
s
simon.vergauwen
10/16/2023, 8:06 AMAha.. it's defined on
Raise<E> Copy code
suspend fun collectData() = either {
parZipOrAccumulate(
{ catch { fetchFromHttp1() }.bind() },
{ catch { fetchFromHttp2() }.bind() },
{ catch { fetchFromHttp3() }.bind() }
) { r1, r2, r3 ->
dbRepository.save(Entity(r1, r2, r3))
.onLeft {
log.error(it.map { it.message }.joinToString("\n", "\n"))
}
}
}There is 1
bindobject ResultEffectobjectEither<Throwable, A>#getOrThrowHIDDENj
Jörg Winter
10/16/2023, 12:23 PMtrying your latest suggestion gives me:
or this, without the type parameters:
s
simon.vergauwen
10/16/2023, 12:32 PMCould you provide a small snippet with imports?
j
Jörg Winter
10/16/2023, 1:01 PM Copy code
import arrow.core.Either.Companion.catch
import arrow.core.raise.either
import arrow.fx.coroutines.parZipOrAccumulate
import org.springframework.stereotype.Service
@Service
class DataCollectionService(
) {
suspend fun collectAndSave() {
either {
parZipOrAccumulate(
{ catch { fetchSomeHttp1() }.bind() },
{ catch { fetchSomeHttp2() }.bind() },
{ catch { fetchSomeHttp3() }.bind() }
) { result1: String, result2: String, result3: String ->
// TODO what ever with results
}
}
}
private fun fetchSomeHttp1(): String {
return "r1"
}
private fun fetchSomeHttp2(): String {
return "r2"
}
private fun fetchSomeHttp3(): String {
return "r3"
}
}..in which
s
simon.vergauwen
10/16/2023, 1:51 PMAh, ye it's not able to automatically infer the type 😞 So I think you need,
either<Throwable, A> { }j
Jörg Winter
10/16/2023, 3:58 PMyep.. almost. I had to provide a transformation as 1st parameter also, now it works nicely:
Copy code
either<Throwable, Unit> {
parZipOrAccumulate(
{ throwable, throwable2 -> RuntimeException(throwable.message + throwable2.message) },
{ catch { fetchSomeHttp1() }.bind() },
{ catch { fetchSomeHttp2() }.bind() },
{ catch { fetchSomeHttp3() }.bind() }
) { result1, result2, result3 ->
// some side-effect of type Unit
}
}.onLeft { left -> log.error(left.message) }Thanks
definetly nicer than my initial attempt
s
simon.vergauwen
10/17/2023, 6:29 AMOh, I'm sorry 😄 If you put
either<NonEmptyList<Throwable>, Unit> { }throwable.apply { addSuppressed(throwable2) }4 Views