CircuitBreakerBidi

A bidi GraphStage that is joined with a Flow to add Circuit Breaker functionality. When the joined Flow is having trouble responding in time or is responding with failures, then based on the provided settings, it short circuits the Flow: Instead of pushing an element to the joined Flow, it directly pushes down a Failure or a fallback response to downstream, given that there is downstream demand.

CircuitBreakerSettings.circuitBreakerState that keeps circuit breaker state. The user can select a CircuitBreakerState implementation that is right for the use case. Please note, in many scenarios, a CircuitBreakerState might need to be shared across materializations or even different streams. In such scenarios, make sure to select a CircuitBreakerState implementation that can work across materializations concurrently.

A CircuitBreakerSettings.fallback function provides an alternative response when circuit is OPEN.

The joined Flow pushes down a Try. By default, any Failure is considered a problem and causes the circuit breaker failure count to be incremented. However, CircuitBreakerSettings.failureDecider can be used to decide on if an element passed by the joined Flow is actually considered a failure. For instance, if Circuit Breaker is joined with an Akka HTTP flow, a Success Http Response with status code 500 internal server error should be considered a failure.

Emits when an element is available from the joined Flow or a short circuited element is available

Backpressures when the downstream backpressures

Completes when upstream completes

Cancels when downstream cancels

Please note, if the upstream does not control the throughput, then the throughput of the stream might temporarily increase once the circuit is OPEN: The downstream demand will be addressed with short circuit/fallback messages, which might (or might not) take less time than it takes the joined Flow to process an element. To eliminate this problem, a throttle can be applied specifically for circuit breaker related messages.

                       +------+
      (In, Context) ~> |      | ~> (In, Context)
                       | bidi |
(Try[Out], Context) <~ |      | <~ (Try[Out], Context)
                       +------+

In: the type of the elements pulled from the upstream along with the Context and pushed down to joined flow
Out: the type that's contained in a Try and pushed downstream along with the Context
Context: the type of the context that is carried around along with the elements. The context may be of any type that can be used to uniquely identify each element

Linear Supertypes

GraphStage[BidiShape[(In, Context), (In, Context), (Try[Out], Context), (Try[Out], Context)]], GraphStageWithMaterializedValue[BidiShape[(In, Context), (In, Context), (Try[Out], Context), (Try[Out], Context)], NotUsed], Graph[BidiShape[(In, Context), (In, Context), (Try[Out], Context), (Try[Out], Context)], NotUsed], AnyRef, Any

Type Members

type Shape = BidiShape[(In, Context), (In, Context), (Try[Out], Context), (Try[Out], Context)]

Definition Classes
Graph

Value Members

final def !=(arg0: Any): Boolean

Definition Classes
AnyRef → Any
final def ##(): Int

Definition Classes
AnyRef → Any
final def ==(arg0: Any): Boolean

Definition Classes
AnyRef → Any
def addAttributes(attr: Attributes): Graph[BidiShape[(In, Context), (In, Context), (Try[Out], Context), (Try[Out], Context)], NotUsed]

Definition Classes
Graph
final def asInstanceOf[T0]: T0

Definition Classes
Any
def async: Graph[BidiShape[(In, Context), (In, Context), (Try[Out], Context), (Try[Out], Context)], NotUsed]

Definition Classes
Graph
def clone(): AnyRef

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( ... )
def createLogic(inheritedAttributes: Attributes): GraphStageLogic

Definition Classes
CircuitBreakerBidi → GraphStage
final def createLogicAndMaterializedValue(inheritedAttributes: Attributes): (GraphStageLogic, NotUsed)

Definition Classes
GraphStage → GraphStageWithMaterializedValue
final def eq(arg0: AnyRef): Boolean

Definition Classes
AnyRef
def equals(arg0: Any): Boolean

Definition Classes
AnyRef → Any
def finalize(): Unit

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( classOf[java.lang.Throwable] )
final def getClass(): Class[_]

Definition Classes
AnyRef → Any
def hashCode(): Int

Definition Classes
AnyRef → Any
def initialAttributes: Attributes

Definition Classes
CircuitBreakerBidi → GraphStageWithMaterializedValue
final def isInstanceOf[T0]: Boolean

Definition Classes
Any
final lazy val module: Module

Definition Classes
GraphStageWithMaterializedValue → Graph
def named(name: String): Graph[BidiShape[(In, Context), (In, Context), (Try[Out], Context), (Try[Out], Context)], NotUsed]

Definition Classes
Graph
final def ne(arg0: AnyRef): Boolean

Definition Classes
AnyRef
final def notify(): Unit

Definition Classes
AnyRef
final def notifyAll(): Unit

Definition Classes
AnyRef
val shape: BidiShape[(In, Context), (In, Context), (Try[Out], Context), (Try[Out], Context)]

Definition Classes
CircuitBreakerBidi → Graph
final def synchronized[T0](arg0: ⇒ T0): T0

Definition Classes
AnyRef
def toString(): String

Definition Classes
CircuitBreakerBidi → AnyRef → Any
final def wait(): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
final def wait(arg0: Long, arg1: Int): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
final def wait(arg0: Long): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
final def withAttributes(attr: Attributes): Graph[BidiShape[(In, Context), (In, Context), (Try[Out], Context), (Try[Out], Context)], NotUsed]

Definition Classes
GraphStageWithMaterializedValue → Graph

Related Docs: object CircuitBreakerBidi | package circuitbreaker

class CircuitBreakerBidi[In, Out, Context] extends GraphStage[BidiShape[(In, Context), (In, Context), (Try[Out], Context), (Try[Out], Context)]]

Type Members

type Shape = BidiShape[(In, Context), (In, Context), (Try[Out], Context), (Try[Out], Context)]

Value Members

final def !=(arg0: Any): Boolean

final def ##(): Int

final def ==(arg0: Any): Boolean

def addAttributes(attr: Attributes): Graph[BidiShape[(In, Context), (In, Context), (Try[Out], Context), (Try[Out], Context)], NotUsed]

final def asInstanceOf[T0]: T0

def async: Graph[BidiShape[(In, Context), (In, Context), (Try[Out], Context), (Try[Out], Context)], NotUsed]

def clone(): AnyRef

def createLogic(inheritedAttributes: Attributes): GraphStageLogic

final def createLogicAndMaterializedValue(inheritedAttributes: Attributes): (GraphStageLogic, NotUsed)

final def eq(arg0: AnyRef): Boolean

def equals(arg0: Any): Boolean

def finalize(): Unit

final def getClass(): Class[_]

def hashCode(): Int

def initialAttributes: Attributes

final def isInstanceOf[T0]: Boolean

final lazy val module: Module

def named(name: String): Graph[BidiShape[(In, Context), (In, Context), (Try[Out], Context), (Try[Out], Context)], NotUsed]

final def ne(arg0: AnyRef): Boolean

final def notify(): Unit

final def notifyAll(): Unit

val shape: BidiShape[(In, Context), (In, Context), (Try[Out], Context), (Try[Out], Context)]

final def synchronized[T0](arg0: ⇒ T0): T0

def toString(): String

final def wait(): Unit

final def wait(arg0: Long, arg1: Int): Unit

final def wait(arg0: Long): Unit

final def withAttributes(attr: Attributes): Graph[BidiShape[(In, Context), (In, Context), (Try[Out], Context), (Try[Out], Context)], NotUsed]

Inherited from GraphStage[BidiShape[(In, Context), (In, Context), (Try[Out], Context), (Try[Out], Context)]]

Inherited from GraphStageWithMaterializedValue[BidiShape[(In, Context), (In, Context), (Try[Out], Context), (Try[Out], Context)], NotUsed]

Inherited from Graph[BidiShape[(In, Context), (In, Context), (Try[Out], Context), (Try[Out], Context)], NotUsed]

Inherited from AnyRef

Inherited from Any

Ungrouped