Circuit Breaker Generator

The circuit breaker generator creates a strongly typed CircuitBreakerPolicy<TResult> factory from declarative attributes. It is useful when resilience rules should live next to the operation contract while still producing the same runtime policy as the fluent API.

[GenerateCircuitBreakerPolicy(
    typeof(FulfillmentResponse),
    FactoryMethodName = "CreateGeneratedPolicy",
    PolicyName = "fulfillment-gateway",
    FailureThreshold = 2,
    BreakDurationMilliseconds = 30000)]
public static partial class FulfillmentCircuitBreakerPolicy
{
    [CircuitBreakerResultPredicate]
    private static bool ShouldOpen(FulfillmentResponse response)
        => response.StatusCode == 408 || response.StatusCode == 429 || response.StatusCode >= 500;

    [CircuitBreakerExceptionPredicate]
    private static bool ShouldOpen(Exception exception)
        => exception is TimeoutException;
}

The generated factory returns PatternKit.Cloud.CircuitBreaker.CircuitBreakerPolicy<FulfillmentResponse> and applies any declared result and exception predicates.

Rules

• The host type must be partial.
• FailureThreshold must be at least 1.
• BreakDurationMilliseconds must be non-negative.
• Result predicates must be static bool methods with one TResult parameter.
• Exception predicates must be static bool methods with one Exception parameter.

Diagnostics use the PKCB prefix.