fs2-cron

Examples

import cats.effect.IO
import cats.effect.unsafe.implicits.global
import fs2.Stream
import java.time.LocalTime
val printTime = Stream.eval(IO(println(LocalTime.now)))

Using Cron4s library

import cron4s.Cron
import eu.timepit.fs2cron.cron4s.Cron4sScheduler
val cronScheduler = Cron4sScheduler.systemDefault[IO]
// cronScheduler: eu.timepit.fs2cron.Scheduler[IO, cron4s.expr.CronExpr] = eu.timepit.fs2cron.cron4s.Cron4sScheduler$$anon1ドル@25eea02a
val evenSeconds = Cron.unsafeParse("*/2 * * ? * *")
// evenSeconds: cron4s.package.CronExpr = CronExpr(
// seconds = */2,
// minutes = *,
// hours = *,
// daysOfMonth = ?,
// months = *,
// daysOfWeek = *
// )
val scheduled = cronScheduler.awakeEvery(evenSeconds) >> printTime
// scheduled: Stream[[x]IO[x], Unit] = Stream(..)
scheduled.take(3).compile.drain.unsafeRunSync()
// 12:17:48.032770646
// 12:17:50.001097222
// 12:17:52.000732258

val everyFiveSeconds = Cron.unsafeParse("*/5 * * ? * *")
// everyFiveSeconds: cron4s.package.CronExpr = CronExpr(
// seconds = */5,
// minutes = *,
// hours = *,
// daysOfMonth = ?,
// months = *,
// daysOfWeek = *
// )
val scheduledTasks = cronScheduler.schedule(List(
 evenSeconds -> Stream.eval(IO(println(LocalTime.now.toString + " task 1"))),
 everyFiveSeconds -> Stream.eval(IO(println(LocalTime.now.toString + " task 2")))
))
// scheduledTasks: Stream[IO, Unit] = Stream(..)
scheduledTasks.take(9).compile.drain.unsafeRunSync()
// 12:17:54.001309092 task 1
// 12:17:55.002303004 task 2
// 12:17:56.001378253 task 1
// 12:17:58.001008992 task 1
// 12:18:00.001058382 task 2
// 12:18:00.001275186 task 1
// 12:18:02.001425277 task 1
// 12:18:04.002083568 task 1
// 12:18:05.001522523 task 2

Cancelling the scheduled task

import cats.effect._
import cron4s.Cron
import eu.timepit.fs2cron.cron4s.Cron4sScheduler
import fs2.Stream
import fs2.concurrent.SignallingRef
import java.time.LocalTime
import scala.concurrent.duration._
object TestApp extends IOApp.Simple {
 val printTime = Stream.eval(IO(println(LocalTime.now)))
 override def run: IO[Unit] = {
 val cronScheduler = Cron4sScheduler.systemDefault[IO]
 val evenSeconds = Cron.unsafeParse("*/2 * * ? * *")
 val scheduled = cronScheduler.awakeEvery(evenSeconds) >> printTime
 val cancel = SignallingRef[IO, Boolean](false)
 for {
 c <- cancel
 s <- scheduled.interruptWhen(c).repeat.compile.drain.start
 //prints about 5 times before stop
 _ <- Temporal[IO].sleep(10.seconds) >> c.set(true)
 } yield s
 }
}

Using Calev library

import com.github.eikek.calev.CalEvent
import eu.timepit.fs2cron.calev.CalevScheduler
val calevScheduler = CalevScheduler.systemDefault[IO]
// calevScheduler: eu.timepit.fs2cron.Scheduler[IO, CalEvent] = eu.timepit.fs2cron.calev.CalevScheduler$$anon1ドル@19ab8621
val oddSeconds = CalEvent.unsafe("*-*-* *:*:1/2")
// oddSeconds: CalEvent = CalEvent(
// weekday = All,
// date = DateEvent(year = All, month = All, day = All),
// time = TimeEvent(
// hour = All,
// minute = All,
// seconds = List(values = Vector(Single(value = 1, rep = Some(value = 2))))
// ),
// zone = None
// )
val calevScheduled = calevScheduler.awakeEvery(oddSeconds) >> printTime
// calevScheduled: Stream[[x]IO[x], Unit] = Stream(..)
calevScheduled.take(3).compile.drain.unsafeRunSync()
// 12:18:07.018297857
// 12:18:09.000317064
// 12:18:11.000249817

val everyFourSeconds = CalEvent.unsafe("*-*-* *:*:0/4")
// everyFourSeconds: CalEvent = CalEvent(
// weekday = All,
// date = DateEvent(year = All, month = All, day = All),
// time = TimeEvent(
// hour = All,
// minute = All,
// seconds = List(values = Vector(Single(value = 0, rep = Some(value = 4))))
// ),
// zone = None
// )
val calevScheduledTasks = calevScheduler.schedule(List(
 oddSeconds -> Stream.eval(IO(println(LocalTime.now.toString + " task 1"))),
 everyFourSeconds -> Stream.eval(IO(println(LocalTime.now.toString + " task 2")))
))
// calevScheduledTasks: Stream[IO, Unit] = Stream(..)
calevScheduledTasks.take(9).compile.drain.unsafeRunSync()
// 12:18:12.000451379 task 2
// 12:18:13.000994389 task 1
// 12:18:15.000405413 task 1
// 12:18:16.001177876 task 2
// 12:18:17.001266828 task 1
// 12:18:19.000612835 task 1
// 12:18:20.000679117 task 2
// 12:18:21.000881674 task 1
// 12:18:23.000535002 task 1

Using fs2-cron

libraryDependencies ++= Seq(
 "eu.timepit" %% "fs2-cron-cron4s" % "0.10.2" //and/or
 "eu.timepit" %% "fs2-cron-calev" % "0.10.2"
)

License