itv / quartz4s   1.0.4

GitHub

Quarts scheduler library based on cats-effect

Scala versions: 2.12 2.13 3.x

quartz4s

Quarts scheduler library using cats-effect queues for handling results.

Import

libraryDependencies ++= Seq(
  "com.itv" %% "quartz4s-core"     % "1.0.5+12-d29e6643-SNAPSHOT",
)

The project uses a quartz scheduler, and as scheduled messages are generated from Quartz they are decoded and put onto an cats.effect.std.Queue.

Components for scheduling jobs:

  • a QuartzTaskScheduler[F[_], A] which schedules jobs of type A
  • a JobDataEncoder[A] which encodes job data in a map for the given job of type A

Components for responding to scheduled messages:

  • a job factory which is triggered by quartz when a scheduled task occurs and creates messages to put on the queue
  • a JobDecoder[A] which decodes the incoming message data map into an A
  • the decoded message is put onto the provided cats.effect.std.Queue

Usage:

Create some job types

We need to have a set of types to encode and decode. We provide the ability to encode/decode an object as a Map[String, String], which works perfectly for putting data into the quartz JobDataMap. (Heavily inspired by extruder).

import com.itv.scheduler.{JobDataEncoder, JobDecoder}
import com.itv.scheduler.extruder.semiauto._

sealed trait ParentJob
case object ChildObjectJob     extends ParentJob
case class UserJob(id: String) extends ParentJob

object ParentJob {
  implicit val jobDataEncoder: JobDataEncoder[ParentJob] = deriveJobEncoder[ParentJob]
  implicit val jobDecoder: JobDecoder[ParentJob]         = deriveJobDecoder[ParentJob]
  //or, simply: implicit val jobCodec: JobCodec[ParentJob] = deriveJobCodec[ParentJob]
}

Create a JobFactory

There are 2 options when creating a CallbackJobFactory: auto-acked and manually acked messages.

Auto-Acked messages

Scheduled jobs from quartz are immediately acked and the resulting message of type A is placed on a Queue[F, A]. If the message taken from the queue isn't handled cleanly then the resulting quartz job won't be re-run, as it has already been marked as successful.

import cats.effect._
import com.itv.scheduler._
import cats.effect.std.Queue
import cats.effect.unsafe.implicits.global

val jobMessageQueue = Queue.unbounded[IO, ParentJob].unsafeRunSync()
// jobMessageQueue: Queue[[A >: Nothing <: Any] => IO[A], ParentJob] = cats.effect.std.Queue$BoundedQueue@461ee05a
val autoAckJobFactory = MessageQueueJobFactory.autoAcking[IO, ParentJob](jobMessageQueue)
// autoAckJobFactory: Resource[[A >: Nothing <: Any] => IO[A], AutoAckingQueueJobFactory[[A >: Nothing <: Any] => IO[A], ParentJob]] = Bind(
//   source = Bind(
//     source = Bind(
//       source = Allocate(
//         resource = cats.effect.kernel.Resource$$$Lambda$15134/0x0000000804148840@7bb872ea
//       ),
//       fs = cats.effect.kernel.Resource$$Lambda$15136/0x000000080414a040@4c3acfdb
//     ),
//     fs = cats.effect.std.Dispatcher$$$Lambda$15137/0x000000080414b040@89f3d7e
//   ),
//   fs = cats.effect.kernel.Resource$$Lambda$15136/0x000000080414a040@5de0523b
// )

Manually Acked messages

Scheduled jobs are received but only acked with quartz once the handler has completed via an acker: MessageAcker[F, A].

Scheduled jobs from quartz are bundled into a message: A and an acker: MessageAcker[F, A]. The items in the queue are each a Resource[F, A] which uses the message and acks the message as the Resource is used.

Alternatively the lower-level way of handling each message is via a queue of AckableMessage[F, A](message: A, acker: MessageAcker[F, A]) items where the message is explicitly acked by the user.

In both cases, the quartz job is only marked as complete once the acker.complete(result: Either[Throwable, Unit]) is called.

// each message is wrapped as a `Resource` which acks on completion
val ackableJobResourceMessageQueue = Queue.unbounded[IO, Resource[IO, ParentJob]].unsafeRunSync()
// ackableJobResourceMessageQueue: Queue[[A >: Nothing <: Any] => IO[A], Resource[[A >: Nothing <: Any] => IO[A], ParentJob]] = cats.effect.std.Queue$BoundedQueue@12b71557
val ackingResourceJobFactory: Resource[IO, AckingQueueJobFactory[IO, Resource, ParentJob]] =
  MessageQueueJobFactory.ackingResource(ackableJobResourceMessageQueue)
// ackingResourceJobFactory: Resource[[A >: Nothing <: Any] => IO[A], AckingQueueJobFactory[[A >: Nothing <: Any] => IO[A], Resource, ParentJob]] = Bind(
//   source = Bind(
//     source = Bind(
//       source = Allocate(
//         resource = cats.effect.kernel.Resource$$$Lambda$15134/0x0000000804148840@86954cd
//       ),
//       fs = cats.effect.kernel.Resource$$Lambda$15136/0x000000080414a040@796cec73
//     ),
//     fs = cats.effect.std.Dispatcher$$$Lambda$15137/0x000000080414b040@264218ef
//   ),
//   fs = cats.effect.kernel.Resource$$Lambda$15136/0x000000080414a040@c75acdd
// )

// each message is wrapped as a `AckableMessage` which acks on completion
val ackableJobMessageQueue = Queue.unbounded[IO, AckableMessage[IO, ParentJob]].unsafeRunSync()
// ackableJobMessageQueue: Queue[[A >: Nothing <: Any] => IO[A], AckableMessage[[A >: Nothing <: Any] => IO[A], ParentJob]] = cats.effect.std.Queue$BoundedQueue@4ef85ea2
val ackingJobFactory: Resource[IO, AckingQueueJobFactory[IO, AckableMessage, ParentJob]] =
  MessageQueueJobFactory.acking(ackableJobMessageQueue)
// ackingJobFactory: Resource[[A >: Nothing <: Any] => IO[A], AckingQueueJobFactory[[A >: Nothing <: Any] => IO[A], [F >: Nothing <: [_$3 >: Nothing <: Any] => Any, A >: Nothing <: Any] => AckableMessage[F, A], ParentJob]] = Bind(
//   source = Bind(
//     source = Bind(
//       source = Allocate(
//         resource = cats.effect.kernel.Resource$$$Lambda$15134/0x0000000804148840@50e92c7a
//       ),
//       fs = cats.effect.kernel.Resource$$Lambda$15136/0x000000080414a040@665ac3e8
//     ),
//     fs = cats.effect.std.Dispatcher$$$Lambda$15137/0x000000080414b040@47e898ba
//   ),
//   fs = cats.effect.kernel.Resource$$Lambda$15136/0x000000080414a040@4b69c3ab
// )

Creating a scheduler

val quartzProperties = QuartzProperties(new java.util.Properties())
// quartzProperties: QuartzProperties = QuartzProperties(properties = {})
val schedulerResource: Resource[IO, QuartzTaskScheduler[IO, ParentJob]] =
  autoAckJobFactory.flatMap { jobFactory => 
    QuartzTaskScheduler[IO, ParentJob](quartzProperties, jobFactory)
  }
// schedulerResource: Resource[[A >: Nothing <: Any] => IO[A], QuartzTaskScheduler[[A >: Nothing <: Any] => IO[A], ParentJob]] = Bind(
//   source = Bind(
//     source = Bind(
//       source = Bind(
//         source = Allocate(
//           resource = cats.effect.kernel.Resource$$$Lambda$15134/0x0000000804148840@7bb872ea
//         ),
//         fs = cats.effect.kernel.Resource$$Lambda$15136/0x000000080414a040@4c3acfdb
//       ),
//       fs = cats.effect.std.Dispatcher$$$Lambda$15137/0x000000080414b040@89f3d7e
//     ),
//     fs = cats.effect.kernel.Resource$$Lambda$15136/0x000000080414a040@5de0523b
//   ),
//   fs = repl.MdocSession$MdocApp$$Lambda$15141/0x000000080414e840@43998d42
// )

Using the scheduler

import java.time.Instant
import org.quartz.{CronExpression, JobKey, TriggerKey}

def scheduleCronJob(scheduler: QuartzTaskScheduler[IO, ParentJob]): IO[Option[Instant]] =
  scheduler.scheduleJob(
    JobKey.jobKey("child-object-job"),
    ChildObjectJob,
    TriggerKey.triggerKey("cron-test-trigger"),
    CronScheduledJob(new CronExpression("* * * ? * *"))
  )

def scheduleSingleJob(scheduler: QuartzTaskScheduler[IO, ParentJob]): IO[Option[Instant]] =
  scheduler.scheduleJob(
    JobKey.jobKey("single-user-job"),
    UserJob("user-123"),
    TriggerKey.triggerKey("scheduled-single-test-trigger"),
    JobScheduledAt(Instant.now.plusSeconds(2))
  )