Full featured Cron scheduling of akka streams

Question

In akka streams it is possible to do the following:

Source.tick(0.seconds, 15.seconds, "Hello")

And your stream will receive tick element "Hello" every 15 seconds. What I'm looking for is the possibility to do the same, but on cron-like schedule e.g. "every monday at 5 pm".

Answer 1

I figured it out. There is an akka plugin akka-quartz-scheduler which allow configuring some quartz schedule configuration like this: Add this section into akka.conf

akka {
  quartz.schedules {
    SomeSchedule {
      expression = "0 0 1 * * ?"
      timezone = "GMT-7"
      description = "Do something every day at 1 a.m. SF time."
    }
  }
}

Then schedule it

    case class Signal(someData: String)

    implicit val system: ActorSystem = ActorSystem("lebulbeaux-system")
    implicit val materializer: ActorMaterializer = ActorMaterializer()
    // needed for the future flatMap/onComplete in the end
    implicit val executionContext: ExecutionContextExecutor = system.dispatcher

    val source: Source[Signal, ActorRef] = Source.actorRef[Signal](100, OverflowStrategy.fail)

    val ref: ActorRef = Flow[Signal].to(Sink.foreach(signal => println(signal.someData))).runWith(source)

    import com.typesafe.akka.extension.quartz.QuartzSchedulerExtension

    QuartzSchedulerExtension(system).schedule("SomeSchedule", ref, Signal("Hello!"))

    // scroll

And now you'll receive a signal message every day at 1 a.m. SF time.

Also, take a look at this issue for more options of using Source.actorRef