https://github.com/j5ik2o/akka-backoff-supervisor-enhancement

Akka BackOffSupervisor Enhancement
https://github.com/j5ik2o/akka-backoff-supervisor-enhancement

akka scala

Last synced: 2 days ago
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Akka BackOffSupervisor Enhancement

• Host: GitHub
• URL: https://github.com/j5ik2o/akka-backoff-supervisor-enhancement
• Owner: j5ik2o
• License: mit
• Created: 2017-03-09T05:09:57.000Z (over 7 years ago)
• Default Branch: develop
• Last Pushed: 2023-12-15T20:19:05.000Z (11 months ago)
• Last Synced: 2024-05-02T01:16:54.546Z (6 months ago)
• Topics: akka, scala
• Language: Scala
• Homepage:
• Size: 36.1 KB
• Stars: 2
• Watchers: 3
• Forks: 0
• Open Issues: 2
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# akka-backoff-supervisor-enhancement

This product is enhancement library to BackOffSupervisor of Akka.

I'm going to propose this enhancement method to akka team after this experiment.

Please give me your opinion.

## Installation

Add the following to your sbt build (Scala 2.11.x, 2.12.x):

### Release Version

```scala

resolvers += "Sonatype OSS Release Repository" at "https://oss.sonatype.org/content/repositories/releases/"

libraryDependencies += "com.github.j5ik2o" %% "akka-backoff-supervisor-enhancement" % "1.0.2"

```

### Snapshot Version

```scala

resolvers += "Sonatype OSS Snapshot Repository" at "https://oss.sonatype.org/content/repositories/snapshots/"

libraryDependencies += "com.github.j5ik2o" %% "akka-backoff-supervisor-enhancement" % "1.0.1-SNAPSHOT"

```

## Usage

You can use the following enhancement methods, and standard methods provided by akka.

These methods provide functions to handle start and stop events of child actors under BackOffSupervisor.

### How to register `onStartChildHandler`/`onStopChildHandler`

The handler that registered by `withOnStartChildHandler`/`withOnStopChildHandler` is called by `BackOffSupervisor` when the child actor is started/stopped.

```scala

val childProps = Props(classOf[ChildActor])

val stopBackOffOptions = Backoff.onStop(childProps, "c1", 100.millis, 3.seconds, 0.2)

    .withOnStartChildHandler { case (supervisorRef, exOpt) =>

        system.log.info(s"on start child: $supervisorRef, $exOpt")

        exOpt.foreach(supervisorRef ! _) // retry to send a message

}.withOnStopChildHandler { supervisorRef => 

  system.log.info(s"on stop child: $supervisorRef")

}

val stopBackOffSupervisor = system.actorOf(BackoffSupervisor.props(stopBackOffOptions))

```

### How to send `ChildStarted`/`ChildStopped` message to EventSubscriber

The `ChildStarted`/`ChildStopped` message is sent by `BackOffSupervisor` when the child actor is started/stopped.

```scala

object EventSubscriber {

  def props: Props = Props[EventSubscriber]

}

class EventSubscriber extends Actor with ActorLogging {

  override def receive: Receive = {

    case ChildStarted(Some(ChildException(msg))) =>

      log.info(s"child actor was started: $ex")

      sender() ! msg // retry to send a message

    case ChildStopped =>

      log.info("child actor was stopped")

  }

}

val eventSubscriber = system.actorRef(EventSubscriber.props)

val childProps = Props(classOf[ChildActor])

val stopBackOffOptions = Backoff.onStop(childProps, "c1", 100.millis, 3.seconds, 0.2)

  .withEventSubscriber(Some(eventSubscriber))

val stopBackOffSupervisor = system.actorOf(BackoffSupervisor.props(stopBackOffOptions))

```

### How to make Custom BackOffSupervisor implementation

The Custom BackOffSupervisor is supported by `BackoffOnRestartSupervisor` or `BackoffSupervisor` if you want to use the `Actor`. This BackOffSupervisor retries to send the message by self.

```scala

object CustomBackOffSupervisor {

  def props(backoffOptions: BackoffOptions): Props =

    Props(new Supervisor(backoffOptions))

}

class CustomBackOffSupervisor(backoffOptions: BackoffOptions)

  extends BackoffOnRestartSupervisor {

  override val minBackoff = backoffOptions.minBackoff

  override val maxBackoff = backoffOptions.maxBackoff

  override val randomFactor = backoffOptions.randomFactor

  override val reset = backoffOptions

    .reset.getOrElse(AutoReset(minBackoff))

  override def childProps: Props = ChildActor.props

  override def childName: String = "child"

  override def handleCommand: Receive = {

    case msg =>

      child.get forward msg

  }

  override def onStartChild(exOpt: Option[Throwable]): Unit =

    exOpt.foreach { case ChildException(msg) =>

      child.get ! msg // retry to send a message

    }

}

val childProps = Props(classOf[ChildActor])

val backOffOptions = Backoff.custom(childProps, "c1", 100.millis, 3.seconds, 0.2)

val backOffSupervisor = system.actorOf(CustomBackOffSupervisor.props(backOffOptions))

```