How to integrate Quarkus with JetBrains Exposed?

[micheljung]

I'm trying to integrate Quarkus JTA with JetBrains Exposed, see also: Integrate with Quarkus/JTA

The problem is basically how to inject a Exposed-aware transaction manager into Narayana Transaction Manager, like it is somehow done for Hibernate ORM:

https://quarkus.io/guides/hibernate-orm#automatic-integration

I tried to copy from https://github.com/quarkusio/quarkus/tree/9070ad725ed552de597a1683c6f864f856ede3b9/extensions/hibernate-orm but I was unable to find the code that does it.

Any hints?

[micheljung]

Found this:

quarkus/extensions/hibernate-orm/runtime/src/main/java/io/quarkus/hibernate/orm/runtime/customized/QuarkusJtaPlatform.java

Line 41 in 9070ad7

public TransactionManager retrieveTransactionManager() {

I don't understand this yet but it seems to be the other way around; the Hibernate ORM extension delegates to JTA?

[mschorsch]

@micheljung It should work out-of-the-box If you inject an AgroalDataSource (https://quarkus.io/guides/datasource#consuming-the-datasource) and use the DataSource as input for Exposed because the DataSource ist Transaction aware. Something like this: Database.connect(dataSource). We do something similar with JOOQ and it works great.

[mschorsch]

The only thing that could be problematic ist that Exposed ist using/creating it's own Transaction Manager...

[florentsorel]

@micheljung FYI, I found a solution, but I can't use @Transactional annotation. One day I hope I'll find a way to use @Transactional but it's not today :(

class ActorRepositoryImpl : ActorRepository {
    override fun findAll(): List<Actor> {
        return transaction {
            ActorTable
                .selectAll()
                .map { fromRow(it) }
        }
    }
}

[micheljung]

@florentsorel yes, that's what you're forced to do. But if you want to make 2 repository calls in the same transaction, you're out of luck. Then you need to wrap both calls in a transaction { }. Where would you do that? In the service? In the HTTP endpoint? Whatever you choose, this layer will be polluted with knowledge about Exposed - something that should be an implementation detail of your Repository ☹️ This I wanted to avoid.

[florentsorel]

@micheljung And the @Transacionnal annotation fix what you said? 🤔
Maybe I'll try Ktorm, I just want a query builder not ORM and I like Exposed DSL approach but I think I need someone smarter than me 😞

[mschorsch]

... I just want a query builder not ORM ...

I would recommend JOOQ. It's easy to use, generates typesafe SQL and works out of the box with JTA (e.g. Transactional).

[micheljung]

@florentsorel if @Transactional worked with Exposed, you could use it e.g. in your HTTP endpoint and have your entire request run in a single transaction. Because @Transactional is Jakarta EE API, it's technology-neutral, so the underlying DB client or ORM wouldn't matter and can easily be replaced without touching the way you do transactions. With transaction { } from exposed, this is not possible.