Support use of JTA transaction ?

[scalajos]

Support use of JTA / XA transaction

JTA transactions have some strict threading constraint :
to be part of a JTA transaction, a jdbc action must execute within a thread already bound to a JTA transaction
More specifically:

• obtaining a connection from an xa datasource needs to be done with a thread already bound to a JTA transaction to enroll the jdbc connection (as a XAResource) into the transaction manager
• executing a jdbc statement or any action using a jdbc connection needs to be done with a thread already bound to a JTA transaction

Using blocking IO pool (eg blocking {...}) naively would prevent any use of the library in a JTA context (no way to set XA transaction in thread context of the blocking section)

Here 2 quick ideas I propose but you certainly will find much better ones

1. allow some scoped action in the 'blocking' block to have a chance to access thread and set/unset a JTA context for instance

val scopedEnterExitBlockingSectionAction: ZIO[Scope, ..., Unit] = ... // obtain the 'blocking' customizer

blocking {
  ZIO.scoped {
    for {
      // a scoped zio action (possibly no-op) which could access current thread and set thread context
      // for inst. bind/unbind the current thread with a JTA transaction 
      _ <- scopedEnterExitBlockingJdbcSectionAction 
      // get connection from XA datasource or use some jdbc action
      r <- jdbc action
    } yield r
  }
}

2. allow external custom blocking IO executor

val jdbcBlockIo = ZIO.attempt {
  jdbc action 
}

if (customExecutorDefined) jdbcBlockIo.onExecutor(customExecutor)
else blocking(jdbcBlockIo)

where customExecutor would provide a jdbc IO executor which thread is guaranteed to be bound to a JTA transaction

I understand these are very rough ideas but I really think supporting JTA/XA transactions would be a significant advantage for the library

Best regards

[jdegoes]

@scalajos Sounds good to me!

/bounty $100

[algora-pbc]

💎 $100 bounty • ZIO

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Attempt	Started (GMT+0)	Solution
🔴 @cacapouh	Jun 8, 2023, 8:32:04 AM	WIP

[cacapouh]

/attempt #54

[algora-pbc]

@cacapouh: Reminder that in 7 days the bounty will become up for grabs, so please submit a pull request before then 🙏

[algora-pbc]

The bounty is up for grabs! Everyone is welcome to /attempt #54 🙌