Package akka.stream.scaladsl

Class RestartWithBackoffSink<T>

java.lang.Object

akka.stream.stage.GraphStageWithMaterializedValue<S,NotUsed>

akka.stream.stage.GraphStage<SinkShape<T>>

akka.stream.scaladsl.RestartWithBackoffSink<T>

All Implemented Interfaces:

Graph<SinkShape<T>,NotUsed>

public final class RestartWithBackoffSink<T>
extends GraphStage<SinkShape<T>>

Wrap the given Sink with a Sink that will restart it when it fails or complete using an exponential backoff.

This Sink will not cancel as long as maxRestarts is not reached, since cancellation by the wrapped Sink is handled by restarting it. The wrapped Sink can however be completed by feeding a completion or error into this Sink. When that happens, the Sink, if currently running, will terminate and will not be restarted. This can be triggered simply by the upstream completing, or externally by introducing a KillSwitch right before this Sink in the graph.

The restart process is inherently lossy, since there is no coordination between cancelling and the sending of messages. When the wrapped Sink does cancel, this Sink will backpressure, however any elements already sent may have been lost.

This uses the same exponential backoff algorithm as Backoff.

param: minBackoff minimum (initial) duration until the child actor will started again, if it is terminated param: maxBackoff the exponential back-off is capped to this duration param: randomFactor after calculation of the exponential back-off an additional random delay based on this factor is added, e.g. 0.2 adds up to 20% delay. In order to skip this additional delay pass in 0. param: maxRestarts the amount of restarts is capped to this amount within a time frame of minBackoff. Passing 0 will cause no restarts and a negative number will not cap the amount of restarts. param: sinkFactory A factory for producing the Sink to wrap.

Constructor Summary

Constructors

Constructor	Description
RestartWithBackoffSink(scala.Function0<Sink<T,?>> sinkFactory, scala.concurrent.duration.FiniteDuration minBackoff, scala.concurrent.duration.FiniteDuration maxBackoff, double randomFactor, int maxRestarts)

Method Summary

Modifier and Type	Method	Description
RestartWithBackoffLogic<SinkShape<T>>	createLogic(Attributes inheritedAttributes)
Inlet<T>	in()
SinkShape<T>	shape()	The shape of a graph is all that is externally visible: its inlets and outlets.

Methods inherited from class akka.stream.stage.GraphStage

createLogicAndMaterializedValue

Methods inherited from class akka.stream.stage.GraphStageWithMaterializedValue

createLogicAndMaterializedValue, initialAttributes, traversalBuilder, withAttributes

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface akka.stream.Graph

addAttributes, async, async, async, named

Constructor Detail

RestartWithBackoffSink

public RestartWithBackoffSink(scala.Function0<Sink<T,?>> sinkFactory,
                              scala.concurrent.duration.FiniteDuration minBackoff,
                              scala.concurrent.duration.FiniteDuration maxBackoff,
                              double randomFactor,
                              int maxRestarts)

Method Detail

createLogic

public RestartWithBackoffLogic<SinkShape<T>> createLogic(Attributes inheritedAttributes)

Specified by:

createLogic in class GraphStage<SinkShape<T>>

in

public Inlet<T> in()

shape

public SinkShape<T> shape()

Description copied from interface: Graph

The shape of a graph is all that is externally visible: its inlets and outlets.

Returns:

(undocumented)