Scala-Slick: only part of sequence of actions executed - mysql

Question

Have a piece of code that adds/updates a Product and also associates one or more tags to it. Tags are actually added to a TagGroup and that is associated with the Product.
Issue I am facing is that only "part" of addOrUpdateProductWithTags() executes. Product is updated or created but Tags are not added. If I comment the last query (see comment) then everything works. Have turned on "" to confirm this.
lazy val pRetId = prods returning prods.map(_.id)
def addTags(keywords: Seq[String]) = {
for {
k <- keywords
} yield {
tags.filter(_.keyword === k).take(1).result.headOption.flatMap {
case Some(tag) => {
Logger.debug("Using existing tag: " + k)
DBIO.successful(tag.id)
}
case None => {
Logger.debug("Adding new tag: " + k)
tags.returning(tags.map(_.id)) += Tag(k, Some("DUMMY"))
}
}
}
}
def addOrUpdateProductWithTags(prod: Product, tagSet: Seq[String]): Future[Option[Long]] = {
// handle add or update product
val prodObject = prod.id match {
case 0L => pRetId += prod
case _ => prods.withFilter(_.id === prod.id).update(prod)
}
val action = for {
pid <- prodObject
tids <- DBIO.sequence(addTags(tagSet))
} yield (tids, pid)
val finalAction = action.flatMap {
case (tids, pid) => {
val prodId = if (prod.id > 0L) prod.id else pid.asInstanceOf[Number].longValue
val delAction = tagGroups.filter(_.prodId === prodId).delete
val tgAction = for {
tid <- tids
} yield {
tagGroups += TagGroup("Ignored-XX", prodId, tid)
}
delAction.flatMap { x => DBIO.sequence(tgAction) }
// IF LINE BELOW IS COMMENTED THEN TagGroup is created else even delete above doesn't happen
prods.filter(_.id === prodId).map(_.id).result.headOption
}
}
db.run(finalAction.transactionally)
}
This is the snippet in the controller where this method is called from. My suspicion is that caller doesn't wait long enough but not sure...
val prod = Prod(...)
val tagSet = generateTags(prod.tags)
val add = prodsService.addOrUpdateProductWithTags(prod, tagSet)
add.map { value =>
Redirect(controllers.www.routes.Dashboard.dashboard)
}.recover {
case th =>
InternalServerError("bad things happen in life: " + th)
}
Any clue what's wrong with the query ?
Stack: Scala 2.11.7, play version 2.5.4, play-slick 2.0.0 (slick 3.1)

Answer 1

Finally figured out a solution:
In place of the following 2 lines:
delAction.flatMap { x => DBIO.sequence(tgAction) }
prods.filter(_.id === prodId).map(_.id).result.headOption
I combined the actions with andThen operators as follows:
delAction >> DBIO.sequence(tgAction) >> prods.filter(_.id === prodId).map(_.id).result.headOption
Now the entire sequence gets executed. I still don't know what's wrong with the original solution but this works.