Hey, does `DataLoader`support kotlin coroutines? U...

# graphql-kotlin

[Robert]

Hey, does `DataLoader`support kotlin coroutines?
Using version 2.1.0

Java Example:
https://github.com/ExpediaGroup/graphql-kotlin/blob/master/examples/spring/src/main/kotlin/com/expediagroup/graphql/examples/dataloaders/DataLoaderConfiguration.kt

[Dariusz Kuc]

afaik not natively

[Dariusz Kuc]

you could invoke coroutines from within the data loader logic but i guess you would have to create your own scope

[Dariusz Kuc]

which i guess would break the structured concurrency

[Robert]

any plans, as this lib is called
graphql-kotlin 😇
Or use CompletableFuture.completedFuture
and use a coroutine to return that value?

[Dariusz Kuc]

*I might be wrong as we don’t use it and don’t have much experience with it.

[Dariusz Kuc]

linked config just registers a data loader so unsure how much we would get form it being a coroutine

[Dariusz Kuc]

org.dataloader.DataLoader signatures we dont control

[Dariusz Kuc]

I would love to drop the graphql-java dependency on CompletableFuture and provide some native execution engine

[Dariusz Kuc]

but unsure when (or if) that ever happens

[Robert]

Good Point 👍
Maybe I don't even need a DataLoader at all .. as there are queries with corutines https://github.com/ExpediaGroup/graphql-kotlin/blob/master/examples/spring/src/main/kotlin/com/expediagroup/graphql/examples/query/CoroutineQuery.kt

[Dariusz Kuc]

we don’t use data loader within Expedia so don’t have much experience with using it

[Dariusz Kuc]

my understanding is that it provides you some batching/caching capabilities

[Dariusz Kuc]

guess its usefulness would really depend on the type of the queries you got

[Dariusz Kuc]

for us its not that useful

[Dariusz Kuc]

and yeah all our queries are implemented as coroutines

[Dariusz Kuc]

https://expediagroup.github.io/graphql-kotlin/docs/execution/async-models#coroutines

[Robert]

perfect, will read through that

[Dariusz Kuc]

note: unfortunately due to the dependency on graphql-java CompletableFuture there is still broken parent-child relationship between query handler (e.g. web filters, routing and construction of gql request) and actual query execution

[Dariusz Kuc]

so currently we have coroutine -> completable future -> coroutine

[Dariusz Kuc]

if you need custom coroutine scope (e.g. MDC) for your queries you will need some custom data fetcher that populates it

[Dariusz Kuc]

*thats what we currently do internally, if you find better way let me know 🙂

[Robert]

will let you know