Philiprehberger.CircuitBreaker 0.2.1

Philiprehberger.CircuitBreaker

Standalone circuit breaker with sliding window failure rate, fallback support, half-open probing, and event callbacks.

Installation

dotnet add package Philiprehberger.CircuitBreaker

Usage

using Philiprehberger.CircuitBreaker;

var breaker = new CircuitBreaker(failureThreshold: 3, openDuration: TimeSpan.FromSeconds(10));

breaker.OnOpen = () => Console.WriteLine("Circuit opened!");
breaker.OnClose = () => Console.WriteLine("Circuit closed.");
breaker.OnHalfOpen = () => Console.WriteLine("Circuit half-open, probing...");

var result = breaker.Execute(() => ComputeValue());
var data = await breaker.ExecuteAsync(() => httpClient.GetStringAsync("/api/health"));

Sliding Window Failure Rate

Track the last N results and open the circuit when the failure rate exceeds a threshold, rather than requiring consecutive failures.

var options = new CircuitBreakerOptions(
    FailureThreshold: 50,
    SlidingWindowSize: 100,
    FailureRateThreshold: 0.5
);

var breaker = new CircuitBreaker(options);

Fallback Support

Provide a fallback that runs when the circuit is open instead of throwing CircuitBrokenException.

var result = breaker.Execute(
    () => CallRemoteService(),
    () => GetCachedValue()
);

var data = await breaker.ExecuteAsync(
    () => httpClient.GetStringAsync("/api/data"),
    () => Task.FromResult("{\"fallback\": true}")
);

Success Threshold in Half-Open

Require multiple consecutive successes in half-open state before closing the circuit.

var options = new CircuitBreakerOptions(
    FailureThreshold: 5,
    OpenDuration: TimeSpan.FromSeconds(30),
    SuccessThresholdInHalfOpen: 3
);

var breaker = new CircuitBreaker(options);

Jitter on Open Duration

Add random jitter to the open duration to prevent thundering herd when multiple circuit breakers recover simultaneously.

var options = new CircuitBreakerOptions(
    FailureThreshold: 5,
    OpenDuration: TimeSpan.FromSeconds(30),
    JitterRatio: 0.2
);

var breaker = new CircuitBreaker(options);

Manual Control

breaker.Trip();   // Force the circuit open
breaker.Reset();  // Force the circuit closed

Handling Rejected Requests

try
{
    var result = breaker.Execute(() => CallService());
}
catch (CircuitBrokenException ex)
{
    Console.WriteLine($"State: {ex.State}, retry in {ex.RemainingDuration.TotalSeconds}s");
}

API

CircuitBreaker

CircuitBreakerOptions

CircuitState

CircuitBrokenException

Development

dotnet build src/Philiprehberger.CircuitBreaker.csproj --configuration Release

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License

MIT