Class RestartFlow
Flow
that gets restarted when it completes or fails.
They are useful for graphs that need to run for longer than the Flow
can necessarily guarantee it will, for
example, for Flow
streams that depend on a remote server that may crash or become partitioned. The
RestartFlow ensures that the graph can continue running while the Flow
restarts.
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptiononFailuresWithBackoff
(RestartSettings settings, Creator<Flow<In, Out, ?>> flowFactory) withBackoff
(RestartSettings settings, Creator<Flow<In, Out, ?>> flowFactory)
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Constructor Details
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RestartFlow
public RestartFlow()
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Method Details
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withBackoff
public static <In,Out> Flow<In,Out, withBackoffNotUsed> (RestartSettings settings, Creator<Flow<In, Out, ?>> flowFactory) Wrap the givenFlow
with aFlow
that will restart it when it fails or complete using an exponential backoff.This
Flow
will not cancel, complete or emit a failure, until the opposite end of it has been cancelled or completed. Any termination by theFlow
before that time will be handled by restarting it as long as maxRestarts is not reached. Any termination signals sent to thisFlow
however will terminate the wrappedFlow
, if it's running, and then theFlow
will be allowed to terminate without being restarted.The restart process is inherently lossy, since there is no coordination between cancelling and the sending of messages. A termination signal from either end of the wrapped
Flow
will cause the other end to be terminated, and any in transit messages will be lost. During backoff, thisFlow
will backpressure.This uses the same exponential backoff algorithm as
pekko.pattern.BackoffOpts
.- Parameters:
settings
-RestartSettings
defining restart configurationflowFactory
- A factory for producing theFlow
to wrap.
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onFailuresWithBackoff
public static <In,Out> Flow<In,Out, onFailuresWithBackoffNotUsed> (RestartSettings settings, Creator<Flow<In, Out, ?>> flowFactory) Wrap the givenFlow
with aFlow
that will restart only when it fails that restarts using an exponential backoff.This new
Flow
will not emit failures. Any failure by the originalFlow
(the wrapped one) before that time will be handled by restarting it as long as maxRestarts is not reached. However, any termination signals, completion or cancellation sent to thisFlow
will terminate the wrappedFlow
, if it's running, and then theFlow
will be allowed to terminate without being restarted.The restart process is inherently lossy, since there is no coordination between cancelling and the sending of messages. A termination signal from either end of the wrapped
Flow
will cause the other end to be terminated, and any in transit messages will be lost. During backoff, thisFlow
will backpressure.This uses the same exponential backoff algorithm as
pekko.pattern.BackoffOpts
.- Parameters:
settings
-RestartSettings
defining restart configurationflowFactory
- A factory for producing theFlow
to wrap.
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