I need to process a set of Ids and return the result as zio.Task[List[RelevantReadingRow]]
def getBaselinesForRequestIds(baseLineReqIds: Set[String]): Task[List[RelevantReadingRow]] =
dynamoConnection
.run(
table.getAll("baseline_req_id" in baseLineReqIds)
)
.flatMap(_.toList.separate match {
case (err :: _, _) => ZIO.fail(new Throwable(describe(err)))
case (Nil, relevantReadings) => ZIO.succeed(relevantReadings)
})
The code above works but I need to process them in batches of 25 element as mutch. I have try this but then I get a List of zio.Task
def getBaselinesForRequestIds(baseLineReqIds: Set[String]): Task[List[RelevantReadingRow]] = {
val subSet = baseLineReqIds.grouped(25).toList
val res = for {
rows <- subSet.map(reqIds => dynamoConnection
.run(
table.getAll("baseline_req_id" in reqIds)
).flatMap(e => e.toList.separate match {
case (err :: _, _) => ZIO.fail(new Throwable(describe(err)))
case (Nil, relevantReadings) => ZIO.succeed(relevantReadings)
}))
} yield rows
res // this is List[zio.Task[List[RelevantReadingRow]]]
}
I dont know how to convert back to a zio.Task[List[RelevantReadingRow]]
any sugestion?
CodePudding user response:
You can use ZIO.collectAll to convert List[Task] to Task[List], I thought it was ZIO.sequence..., maybe I'm getting confused with cats...
Following example works with Zio2
package sample
import zio._
object App extends ZIOAppDefault {
case class Result(value: Int) extends AnyVal
val data: List[Task[List[Result]]] = List(
Task { List(Result(1), Result(2)) },
Task { List(Result(3)) }
)
val flattenValues: Task[List[Result]] = for {
values <- ZIO.collectAll { data }
} yield values.flatten
val app = for {
values <- flattenValues
_ <- Console.putStrLn { values }
} yield()
def run = app
}
In particular for your sample ... and assuming that 'separate' it's just an extension method to collect some errors (returns a tuple of error list and result list), and ignoring the method 'describe' to turn an err into a throwable
https://scastie.scala-lang.org/jgoday/XKxVP2ECSFOv4chgSFCckg/7
package sample
import zio._
object App extends ZIOAppDefault {
class DynamoMock {
def run: Task[List[RelevantReadingRow]] = Task {
List(
RelevantReadingRow(1),
RelevantReadingRow(2),
)
}
}
case class RelevantReadingRow(value: Int) extends AnyVal
implicit class ListSeparate(list: List[RelevantReadingRow]) {
def separate: (List[String], List[RelevantReadingRow]) =
(Nil, list)
}
def getBaselinesForRequestIds(baseLineReqIds: Set[String]): Task[List[RelevantReadingRow]] = {
val dynamoConnection = new DynamoMock()
val subSet = baseLineReqIds.grouped(25).toList
val res: List[Task[List[RelevantReadingRow]]] = for {
rows <- subSet.map(reqIds => dynamoConnection
.run.flatMap(e => e.toList.separate match {
case (err :: _, _) => ZIO.fail(new Throwable(err))
case (Nil, relevantReadings) => ZIO.succeed(relevantReadings)
}))
} yield rows
for {
rows <- ZIO.collectAll(res)
} yield rows.flatten
}
val app = for {
values <- getBaselinesForRequestIds(Set("id1", "id2"))
_ <- Console.putStrLn { values }
} yield()
def run = app
}
CodePudding user response:
So, here is an alternative solution based on @jgoday answer
def getBaselinesForRequestIds(baseLineReqIds: Set[String]): Task[List[RelevantReadingRow]] =
for {
values <- ZIO.foreachPar(baseLineReqIds.grouped(25).toList) {
reqIds =>
dynamoConnection
.run(
table.getAll("baseline_req_id" in reqIds)
).flatMap(e => e.toList.separate match {
case (err :: _, _) => ZIO.fail(new Throwable(describe(err)))
case (Nil, relevantReadings) => ZIO.succeed(relevantReadings)
})
}
} yield values.flatten