Class CircuitBreaker

Provides circuit breaker functionality to provide stability when working with "dangerous" operations, e.g. calls to remote systems

Transitions through three states:

In Closed state, calls pass through until the maxFailures count is reached. This causes the circuit breaker to open. Both exceptions and calls exceeding callTimeout are considered failures.
In Open state, calls fail-fast with an exception. After resetTimeout, circuit breaker transitions to half-open state.
In Half-Open state, the first call will be allowed through, if it succeeds the circuit breaker will reset to closed state. If it fails, the circuit breaker will re-open to open state. All calls beyond the first that execute while the first is running will fail-fast with an exception.

Inheritance

Object

CircuitBreaker

Inherited Members

Object.Equals(Object)

Object.Equals(Object, Object)

Object.GetHashCode()

Object.GetType()

Object.MemberwiseClone()

Object.ReferenceEquals(Object, Object)

Object.ToString()

Namespace: Akka.Pattern

Assembly: Akka.dll

Syntax

public class CircuitBreaker

Constructors

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CircuitBreaker(IScheduler, Int32, TimeSpan, TimeSpan)

Create a new CircuitBreaker

Declaration

public CircuitBreaker(IScheduler scheduler, int maxFailures, TimeSpan callTimeout, TimeSpan resetTimeout)

Parameters

Type	Name	Description
IScheduler	scheduler	Reference to Akka scheduler
Int32	maxFailures	Maximum number of failures before opening the circuit
TimeSpan	callTimeout	TimeSpan of time after which to consider a call a failure
TimeSpan	resetTimeout	TimeSpan of time after which to attempt to close the circuit

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CircuitBreaker(IScheduler, Int32, TimeSpan, TimeSpan, TimeSpan, Double)

Create a new CircuitBreaker

Declaration

public CircuitBreaker(IScheduler scheduler, int maxFailures, TimeSpan callTimeout, TimeSpan resetTimeout, TimeSpan maxResetTimeout, double exponentialBackoffFactor)

Parameters

Type	Name	Description
IScheduler	scheduler	Reference to Akka scheduler
Int32	maxFailures	Maximum number of failures before opening the circuit
TimeSpan	callTimeout	TimeSpan of time after which to consider a call a failure
TimeSpan	resetTimeout	TimeSpan of time after which to attempt to close the circuit
TimeSpan	maxResetTimeout
Double	exponentialBackoffFactor

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CircuitBreaker(IScheduler, Int32, TimeSpan, TimeSpan, TimeSpan, Double, Double)

Create a new CircuitBreaker

Declaration

public CircuitBreaker(IScheduler scheduler, int maxFailures, TimeSpan callTimeout, TimeSpan resetTimeout, TimeSpan maxResetTimeout, double exponentialBackoffFactor, double randomFactor)

Parameters

Type	Name	Description
IScheduler	scheduler	Reference to Akka scheduler
Int32	maxFailures	Maximum number of failures before opening the circuit
TimeSpan	callTimeout	TimeSpan of time after which to consider a call a failure
TimeSpan	resetTimeout	TimeSpan of time after which to attempt to close the circuit
TimeSpan	maxResetTimeout
Double	exponentialBackoffFactor
Double	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. randomFactor should be in range `0.0` (inclusive) and `1.0` (inclusive). In order to skip this additional delay pass in `0`.

Properties

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CallTimeout

TBD

Declaration

public TimeSpan CallTimeout { get; }

Property Value

Type	Description
TimeSpan

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CurrentFailureCount

Retrieves current failure count.

Declaration

public long CurrentFailureCount { get; }

Property Value

Type	Description
Int64

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ExponentialBackoffFactor

TBD

Declaration

public double ExponentialBackoffFactor { get; }

Property Value

Type	Description
Double

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IsClosed

Return true if the internal state is Closed. WARNING: It is a "power API" call which you should use with care. Ordinal use cases of CircuitBreaker expects a remote call to return Future, as in WithCircuitBreaker(Func<Task>). So, if you check the state by yourself, and make a remote call outside CircuitBreaker, you should manage the state yourself.

Declaration

public bool IsClosed { get; }

Property Value

Type	Description
Boolean

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IsHalfOpen

Return true if the internal state is HalfOpen. WARNING: It is a "power API" call which you should use with care. Ordinal use cases of CircuitBreaker expects a remote call to return Future, as in withCircuitBreaker. So, if you check the state by yourself, and make a remote call outside CircuitBreaker, you should manage the state yourself.

Declaration

public bool IsHalfOpen { get; }

Property Value

Type	Description
Boolean

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IsOpen

Return true if the internal state is Open. WARNING: It is a "power API" call which you should use with care. Ordinal use cases of CircuitBreaker expects a remote call to return Future, as in WithCircuitBreaker(Func<Task>). So, if you check the state by yourself, and make a remote call outside CircuitBreaker, you should manage the state yourself.

Declaration

public bool IsOpen { get; }

Property Value

Type	Description
Boolean

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LastCaughtException

Declaration

public Exception LastCaughtException { get; }

Property Value

Type	Description
Exception

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MaxFailures

TBD

Declaration

public int MaxFailures { get; }

Property Value

Type	Description
Int32

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MaxResetTimeout

TBD

Declaration

public TimeSpan MaxResetTimeout { get; }

Property Value

Type	Description
TimeSpan

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RandomFactor

TBD

Declaration

public double RandomFactor { get; }

Property Value

Type	Description
Double

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ResetTimeout

TBD

Declaration

public TimeSpan ResetTimeout { get; }

Property Value

Type	Description
TimeSpan

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Scheduler

TBD

Declaration

public IScheduler Scheduler { get; }

Property Value

Type	Description
IScheduler

Methods

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Create(IScheduler, Int32, TimeSpan, TimeSpan)

Create a new CircuitBreaker

Declaration

public static CircuitBreaker Create(IScheduler scheduler, int maxFailures, TimeSpan callTimeout, TimeSpan resetTimeout)

Parameters

Type	Name	Description
IScheduler	scheduler	Reference to Akka scheduler
Int32	maxFailures	Maximum number of failures before opening the circuit
TimeSpan	callTimeout	TimeSpan of time after which to consider a call a failure
TimeSpan	resetTimeout	TimeSpan of time after which to attempt to close the circuit

Returns

Type	Description
CircuitBreaker	TBD

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Fail()

Mark a failed call through CircuitBreaker. Sometimes the callee of CircuitBreaker sends back a message to the caller Actor. In such a case, it is convenient to mark a failed call instead of using Future via WithCircuitBreaker(Func<Task>)

Declaration

public void Fail()

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OnClose(Action)

Adds a callback to execute when circuit breaker state closes

Declaration

public CircuitBreaker OnClose(Action callback)

Parameters

Type	Name	Description
Action	callback	Action Handler to be invoked on state change

Returns

Type	Description
CircuitBreaker	CircuitBreaker for fluent usage

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OnHalfOpen(Action)

Adds a callback to execute when circuit breaker transitions to half-open

Declaration

public CircuitBreaker OnHalfOpen(Action callback)

Parameters

Type	Name	Description
Action	callback	Action Handler to be invoked on state change

Returns

Type	Description
CircuitBreaker	CircuitBreaker for fluent usage

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OnOpen(Action)

Adds a callback to execute when circuit breaker opens

Declaration

public CircuitBreaker OnOpen(Action callback)

Parameters

Type	Name	Description
Action	callback	Action Handler to be invoked on state change

Returns

Type	Description
CircuitBreaker	CircuitBreaker for fluent usage

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Succeed()

Mark a successful call through CircuitBreaker. Sometimes the callee of CircuitBreaker sends back a message to the caller Actor. In such a case, it is convenient to mark a successful call instead of using Future via WithCircuitBreaker(Func<Task>)

Declaration

public void Succeed()

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WithCircuitBreaker(Func<Task>)

Wraps invocation of asynchronous calls that need to be protected

Declaration

public Task WithCircuitBreaker(Func<Task> body)

Parameters

Type	Name	Description
Func<Task>	body	Call needing protected

Returns

Type	Description
Task	Task

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WithCircuitBreaker<TState>(TState, Func<TState, Task>)

Declaration

public Task WithCircuitBreaker<TState>(TState state, Func<TState, Task> body)

Parameters

Type	Name	Description
TState	state
Func<TState, Task>	body

Returns

Type	Description
Task

Type Parameters

Name	Description
TState

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WithCircuitBreaker<T>(Func<Task<T>>)

Wraps invocation of asynchronous calls that need to be protected

Declaration

public Task<T> WithCircuitBreaker<T>(Func<Task<T>> body)

Parameters

Type	Name	Description
Func<Task<T>>	body	Call needing protected

Returns

Type	Description
Task<T>	Task containing the call result

Type Parameters

Name	Description
T	TBD

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WithCircuitBreaker<T, TState>(TState, Func<TState, Task<T>>)

Declaration

public Task<T> WithCircuitBreaker<T, TState>(TState state, Func<TState, Task<T>> body)

Parameters

Type	Name	Description
TState	state
Func<TState, Task<T>>	body

Returns

Type	Description
Task<T>

Type Parameters

Name	Description
T
TState

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WithExponentialBackoff(TimeSpan)

The ResetTimeout will be increased exponentially for each failed attempt to close the circuit. The default exponential backoff factor is 2.

Declaration

public CircuitBreaker WithExponentialBackoff(TimeSpan maxResetTimeout)

Parameters

Type	Name	Description
TimeSpan	maxResetTimeout	The upper bound of ResetTimeout

Returns

Type	Description
CircuitBreaker

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WithRandomFactor(Double)

Adds jitter to the delay.

Declaration

public CircuitBreaker WithRandomFactor(double randomFactor)

Parameters

Type	Name	Description
Double	randomFactor	after calculation of the 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.

Returns

Type	Description
CircuitBreaker

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WithSyncCircuitBreaker(Action)

Wraps invocations of asynchronous calls that need to be protected.

Declaration

public void WithSyncCircuitBreaker(Action body)

Parameters

Type	Name	Description
Action	body	Call needing protected

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WithSyncCircuitBreaker<T>(Func<T>)

Wraps invocations of asynchronous calls that need to be protected.

Declaration

public T WithSyncCircuitBreaker<T>(Func<T> body)

Parameters

Type	Name	Description
Func<T>	body	Call needing protected

Returns

Type	Description
T	The result of the call

Type Parameters

Name	Description
T

Extension Methods

ObjectExtensions.IsDefaultForType<T>(T)

ObjectExtensions.AsOption<T>(T)

Extensions.AsInstanceOf<T>(Object)