fs2-cron
fs2-cron is a microlibrary that provides FS2 streams based on Cron4s cron expressions.
Examples
import cats.effect.{IO, Timer}
import cron4s.Cron
import eu.timepit.fs2cron.awakeEveryCron
import fs2.Stream
import java.time.LocalTime
import scala.concurrent.ExecutionContext
implicit val timer: Timer[IO] = IO.timer(ExecutionContext.global)
val evenSeconds = Cron.unsafeParse("*/2 * * ? * *")
// evenSeconds: cron4s.CronExpr = */2 * * ? * *
val printTime = Stream.eval(IO(println(LocalTime.now)))
// printTime: fs2.Stream[cats.effect.IO,Unit] = Stream(..)
val scheduled = awakeEveryCron[IO](evenSeconds) >> printTime
// scheduled: fs2.Stream[[x]cats.effect.IO[x],Unit] = Stream(..)
scheduled.take(3).compile.drain.unsafeRunSync
// 05:44:52.290
// 05:44:54.006
// 05:44:56.005
import cats.effect.ContextShift
import eu.timepit.fs2cron.schedule
implicit val ctxShift: ContextShift[IO] = IO.contextShift(ExecutionContext.global)
val everyFiveSeconds = Cron.unsafeParse("*/5 * * ? * *")
// everyFiveSeconds: cron4s.CronExpr = */5 * * ? * *
val scheduledTasks = schedule(List(
evenSeconds -> Stream.eval(IO(println(LocalTime.now.toString + " task 1"))),
everyFiveSeconds -> Stream.eval(IO(println(LocalTime.now.toString + " task 2")))
))
// scheduledTasks: fs2.Stream[[+A]cats.effect.IO[A],Unit] = Stream(..)
scheduledTasks.take(9).compile.drain.unsafeRunSync
// 05:44:58.003 task 1
// 05:45:00.007 task 1
// 05:45:00.007 task 2
// 05:45:02.006 task 1
// 05:45:04.007 task 1
// 05:45:05.006 task 2
// 05:45:06.007 task 1
// 05:45:08.005 task 1
// 05:45:10.004 task 2
// 05:45:10.004 task 1
Using fs2-cron
The latest version of the library is available for Scala 2.12 and 2.13.
If you're using sbt, add the following to your build:
libraryDependencies ++= Seq(
"eu.timepit" %% "fs2-cron-core" % "0.2.2"
)
License
fs2-cron is licensed under the Apache License, Version 2.0, available at http://www.apache.org/licenses/LICENSE-2.0 and also in the LICENSE file.