https://stackoverflow.com/questions/58470766/

foo.scala

import monix.eval.Task
import monix.execution.Cancelable
import monix.execution.cancelables.CompositeCancelable

import scala.util.{Failure, Success, Try}


object Foo extends App {
  val things = Range(1, 10)
  val c = CompositeCancelable()
  implicit val scheduler = monix.execution.Scheduler.global

  val futures = things.map(e => {
    val f = t(e)
    (f, Cancelable(()=> {
      f // TODO ref to f?
      println("canceled")
    }))
  })
  // TODO how can the futures be added here / made cancellable?
    futures.foreach(f=> c += f._2)

  def t(i: Int) = Task.eval {
//        Try { // not using a try it at least fails & stops, but I want to also cancel the other tasks
    Thread.sleep(1000)
    val result = i + 1
    if (result > 5) {
      throw new Exception("asdf")
    }
    // i.e. write to file, that's why unit is returned
    println(result) // Effect
    "Result"
//        }
  }

  futures.foreach(f=> {

  })

  futures.par.foreach(_._1.runToFuture.onComplete {
    case Success(value) =>
      println(value)
    case Failure(ex) =>
      c.cancel
      System.err.println(ex)
      println("stopping with error")
      System.exit(1)
  })
}

When including:

futures.foreach(f=> c += f._2)

The result is:

4
2
5
3
Result
Result
Result
Result
java.lang.Exception: asdf
stopping with error
java.lang.Exception: asdf
stopping with error
java.lang.Exception: asdf
stopping with error
Process finished with exit code 1

I.e. a cancel is not performed.