Package org.apache.pekko.actor.typed

Class SupervisorStrategy

java.lang.Object

org.apache.pekko.actor.typed.SupervisorStrategy

Direct Known Subclasses:

BackoffSupervisorStrategy, RestartSupervisorStrategy

public abstract class SupervisorStrategy
extends Object

Not for user extension

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	SupervisorStrategy.Backoff$
static class	SupervisorStrategy.Restart$
static interface	SupervisorStrategy.RestartOrBackoff	INTERNAL API
static class	SupervisorStrategy.Resume$
static class	SupervisorStrategy.Stop$

Constructor Summary

Constructors

Constructor	Description
SupervisorStrategy()

Method Summary

Modifier and Type	Method	Description
abstract boolean	loggingEnabled()
abstract org.slf4j.event.Level	logLevel()
static RestartSupervisorStrategy	restart()	Restart immediately without any limit on number of restart retries.
static BackoffSupervisorStrategy	restartWithBackoff(Duration minBackoff, Duration maxBackoff, double randomFactor)	Java API: It supports exponential back-off between the given minBackoff and maxBackoff durations.
static BackoffSupervisorStrategy	restartWithBackoff(scala.concurrent.duration.FiniteDuration minBackoff, scala.concurrent.duration.FiniteDuration maxBackoff, double randomFactor)	Scala API: It supports exponential back-off between the given minBackoff and maxBackoff durations.
static SupervisorStrategy	resume()	Resume means keeping the same state as before the exception was thrown and is thus less safe than restart.
static SupervisorStrategy	stop()	Stop the actor
abstract SupervisorStrategy	withLoggingEnabled(boolean enabled)
abstract SupervisorStrategy	withLogLevel(org.slf4j.event.Level level)

Methods inherited from class java.lang.Object

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

Constructor Details

SupervisorStrategy

public SupervisorStrategy()

Method Details

resume

public static SupervisorStrategy resume()

Resume means keeping the same state as before the exception was thrown and is thus less safe than restart.

If the actor behavior is deferred and throws an exception on startup the actor is stopped (restarting would be dangerous as it could lead to an infinite restart-loop)

restart

public static RestartSupervisorStrategy restart()

Restart immediately without any limit on number of restart retries. A limit can be added with RestartSupervisorStrategy.withLimit.

If the actor behavior is deferred and throws an exception on startup the actor is stopped (restarting would be dangerous as it could lead to an infinite restart-loop)

stop

public static SupervisorStrategy stop()

Stop the actor

restartWithBackoff

public static BackoffSupervisorStrategy restartWithBackoff(scala.concurrent.duration.FiniteDuration minBackoff,
 scala.concurrent.duration.FiniteDuration maxBackoff,
 double randomFactor)

Scala API: It supports exponential back-off between the given minBackoff and maxBackoff durations. For example, if minBackoff is 3 seconds and maxBackoff 30 seconds the start attempts will be delayed with 3, 6, 12, 24, 30, 30 seconds. The exponential back-off counter is reset if the actor is not terminated within the minBackoff duration.

In addition to the calculated exponential back-off an additional random delay based the given randomFactor is added, e.g. 0.2 adds up to 20% delay. The reason for adding a random delay is to avoid that all failing actors hit the backend resource at the same time.

During the back-off incoming messages are dropped.

If no new exception occurs within (minBackoff + maxBackoff) / 2 the exponentially increased back-off timeout is reset. This can be overridden by explicitly setting resetBackoffAfter using withResetBackoffAfter on the returned strategy.

The strategy is applied also if the actor behavior is deferred and throws an exception during startup.

A maximum number of restarts can be specified with BackoffSupervisorStrategy.withMaxRestarts(int)

Parameters:

minBackoff - minimum (initial) duration until the child actor will started again, if it is terminated

maxBackoff - the exponential back-off is capped to this duration

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.

restartWithBackoff

public static BackoffSupervisorStrategy restartWithBackoff(Duration minBackoff,
 Duration maxBackoff,
 double randomFactor)

Java API: It supports exponential back-off between the given minBackoff and maxBackoff durations. For example, if minBackoff is 3 seconds and maxBackoff 30 seconds the start attempts will be delayed with 3, 6, 12, 24, 30, 30 seconds. The exponential back-off counter is reset if the actor is not terminated within the minBackoff duration.

In addition to the calculated exponential back-off an additional random delay based the given randomFactor is added, e.g. 0.2 adds up to 20% delay. The reason for adding a random delay is to avoid that all failing actors hit the backend resource at the same time.

During the back-off incoming messages are dropped.

If no new exception occurs within (minBackoff + maxBackoff) / 2 the exponentially increased back-off timeout is reset. This can be overridden by explicitly setting resetBackoffAfter using withResetBackoffAfter on the returned strategy.

The strategy is applied also if the actor behavior is deferred and throws an exception during startup.

Parameters:

minBackoff - minimum (initial) duration until the child actor will started again, if it is terminated

maxBackoff - the exponential back-off is capped to this duration

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.

loggingEnabled

public abstract boolean loggingEnabled()

logLevel

public abstract org.slf4j.event.Level logLevel()

withLoggingEnabled

public abstract SupervisorStrategy withLoggingEnabled(boolean enabled)

withLogLevel

public abstract SupervisorStrategy withLogLevel(org.slf4j.event.Level level)