如何为 AsyncCircuitBreakerPolicy 捕获 CircuitState

Question

我有一个 IAsyncPolicy 类型的变量 asyncPolicy，它有一个或多个策略，包括 AsyncCircuitBreakerPolicy。现在我想在 API 调用之前获取特定策略 AsyncCircuitBreakerPolicy，以便我可以提取 Circuit 的状态。

这可能吗？那怎么办下面的代码给出了错误，'IAsyncPolicy' 不包含 'GetPolicy'

的定义

static void Main(string[] args)
    {
        var asyncPolicy = CreateDefaultRetryPolicy();

        var breaker = asyncPolicy.GetPolicy<AsyncCircuitBreakerPolicy>();
        var state = breaker.CircuitState;

        //Web API call follows with asyncPolicy

        Console.ReadKey();
    }

    public static IAsyncPolicy CreateDefaultRetryPolicy()
    {
        var retryPolicy = Policy.Handle<BrokenCircuitException>().WaitAndRetryAsync
            (
                retryCount: 3,
                sleepDurationProvider: attempt => TimeSpan.FromSeconds(Math.Pow(2, attempt))
            );

        var circuitBreaker = Policy.Handle<HttpRequestException>().CircuitBreakerAsync(
        exceptionsAllowedBeforeBreaking: 3,
        durationOfBreak: TimeSpan.FromSeconds(5000),
        onBreak: (exception, timespan, context) => { },
        onReset: (context) => { });

        return Policy.WrapAsync(retryPolicy, circuitBreaker);
    }

Answer 1

.GetPolicy<T>() 是 only for PolicyWraps。从技术上讲，它是 IPolicyWrap.

上的扩展方法

您可以将 CreateDefaultRetryPolicy() 的 return 类型更改为 AsyncPolicyWrap

public static AsyncPolicyWrap CreateDefaultRetryPolicy()

或者你可以在你调用的地方投射 .GetPolicy<T>()

var breaker = ((IPolicyWrap)asyncPolicy).GetPolicy<AsyncCircuitBreakerPolicy>();

如何为 AsyncCircuitBreakerPolicy 捕获 CircuitState

how to capture CircuitState for AsyncCircuitBreakerPolicy

c#

polly