Polly CircuitBreaker extensions for Microsoft.Extensions.DependencyInjection

Polly.CircuitBreaker.DependencyInjection is a Polly CircuitBreaker extensions for Microsoft.Extensions.DependencyInjection.

You can install Polly.CircuitBreaker.DependencyInjection with NuGet:

Install-Package Jyb.Polly.CircuitBreaker.DependencyInjection

To use, with an IServiceCollection instance :

services.AddCircuitBreaker(Configuration);

Or, you don't use IConfiguration

services.AddCircuitBreaker();

CircuitBreaker Factory is registered as scope. You can configure this with the serviceLifetime parameter.

ICircuitBreaker usage

To use sustainable CircuitBreaker, add a dependency on ICircuitBreaker (similar ILogger):

public class CircuitBreakerBehaviour<TRequest, TResponse> : IPipelineBehavior<TRequest, TResponse> where TRequest : IRequest<TResponse>
{
    private readonly ILogger<TRequest> _logger;
    private readonly ICircuitBreaker<TRequest> _cb;

    public CircuitBreakerBehaviour(ILogger<TRequest> logger, ICircuitBreaker<TRequest> cb)
    {
        _logger = logger;
        _cb = cb;
    }

    public Task<TResponse> Handle(TRequest request, CancellationToken cancellationToken, RequestHandlerDelegate<TResponse> next)
    {
        var policy = _cb.GetPolicy<FallbackHandledException>((ex, t) => _logger.LogWarning("Circuit broken."), () => _logger.LogInformation("Circuit reset."));
        return policy.ExecuteAsync(() => next());
    }
}

ICircuitBreaker<CategoryName> always return same object when CategoryName is same. (like a ILogger).

That means you can not change configuration after circuit breaker initialized. (for the first time calling the GetPolicy function with parameters.)

Configuration usage

Starting config with your appsettings.json :

"CircuitBreakerOptions" : {
  "CircuitBreakers" : {
    "category1" : { "ExceptionsAllowedBeforeBreaking" : 1, "DurationOfBreak" : "00:01:00" },
    "category2" : { "ExceptionsAllowedBeforeBreaking" : 2, "DurationOfBreak" : "00:02:00" },
    "category3" : { "ExceptionsAllowedBeforeBreaking" : 3, "DurationOfBreak" : "00:03:00" }
  }
}

Copyright

Copyright (c) Jungyoung bang.

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