Scala Play 2.4 run akka scheduler service on Application start - scala

Question

I want to use Akka scheduler to do some cron jobs in my Play application.
Since Play 2.4 GlobalSettings is not recommended. Anyone has some sample code on how to do that?
Even I tried the simple code from Play docs and it still not working.
class CustomApplicationLoader extends GuiceApplicationLoader() {
val logger: Logger = Logger(this.getClass)
override def builder(context: ApplicationLoader.Context): GuiceApplicationBuilder = {
logger.info("start")
val extra = Configuration("a" -> 1)
initialBuilder
.in(context.environment)
.loadConfig(extra ++ context.initialConfiguration)
.overrides(overrides(context): _*)
}
}
play.application.loader = "com.xxx.CustomApplicationLoader"
Why I can't get the logging message to print?
How I can use Akka on Application start?

Answer 1

This is how do it in my app:
Start of by defining a trait Scheduled.
package scheduled
import akka.actor.Cancellable
trait Scheduled {
var cancellable: Option[Cancellable] = None
val defaultInterval = 60
val secondsToWait = {
import scala.concurrent.duration._
10 seconds
}
def start()
def stop() = {
cancellable.map(_.cancel())
}
}
Then implement Scheduled with Akka magic
package scheduled
import akka.actor.ActorSystem
import play.api.{Configuration, Logger}
import com.google.inject.{Singleton, Inject}
import play.api.libs.concurrent.Execution.Implicits._
trait ScheduledWorker extends Scheduled
#Singleton
class ScheduledWorkerImpl #Inject()(
actorSystem: ActorSystem,
configuration: Configuration
) extends ScheduledWorker {
start()
lazy val intervalKey = "worker.interval"
lazy val jobEnabled = "worker.enabled"
override def start(): Unit = {
import scala.concurrent.duration._
lazy val i = configuration.getInt(intervalKey).getOrElse(defaultInterval)
lazy val isEnabled = Option(System.getProperty(jobEnabled)).getOrElse(
configuration.getString(jobEnabled).getOrElse("false")
).equals("true")
cancellable = isEnabled match {
case true =>
Some(
actorSystem.scheduler.schedule(0 seconds, i minutes) {
.. MAJOR COOL CODE!!! ;))) ...
}
)
case _ => None
}
}
}
create a module to eagerly start the scheduled stuff
package modules
import play.api.{Configuration, Environment}
import play.api.inject.Module
import scheduled.{ScheduledWorker}
class ScheduledModule extends Module {
def bindings(environment: Environment,
configuration: Configuration) = Seq(
bind[ScheduledWorker].to[ScheduledWorkerImpl].eagerly()
)
}
make sure that your config specifies ScheduledModule.
play.modules.enabled += "modules.ScheduledModule"
And voila you have a working scheduled task when your play 2.4 app starts =)