Aspnetcore 健康检查降级状态被忽略

Question

我是根据 MSDN 网站上发布的信息了解 HealthChecks 的：https://docs.microsoft.com/en-us/aspnet/core/host-and-deploy/health-checks?view=aspnetcore-5.0#register-health-check-services

下面的代码片段告诉我，如果一个不健康的检查 returns 我可以通过说它已降级来覆盖该值。

services.AddHealthChecks()
    .AddCheck<ExampleHealthCheck>(
        "example_health_check",
        failureStatus: HealthStatus.Degraded,
        tags: new[] { "example" });

所以我用这个实现尝试了这个，假设我会得到一个退化的结果而不是一个不健康的结果：

public class Startup
{
    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }
    public IConfiguration Configuration { get; }
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddHealthChecks().AddCheck<ExampleHealthCheck>("ExampleHealthCheck", failureStatus: HealthStatus.Degraded);
    }
    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        app.UseRouting();
        app.UseEndpoints(endpoints =>
        {
            endpoints.MapHealthChecks("/health");
        });
    }
}
internal class ExampleHealthCheck : IHealthCheck
{
    public Task<HealthCheckResult> CheckHealthAsync(HealthCheckContext context, CancellationToken cancellationToken = default(CancellationToken))
    {
        return Task.FromResult(HealthCheckResult.Unhealthy("An unhealthy result."));
    }
}

有人能解释一下为什么这不起作用或我在哪里做错了吗？

Answer 1

这很令人困惑，因为您希望 HealthCheck 自动返回您在 failureStatus 属性上定义的结果，但您的 HealthCheck 明确地 returns Unhealthy.

如果您查看 GitHub 上的 AddHealthCheck<T> 方法，您将看到仅创建了 HealthCheckRegistration.

的一个实例

public static IHealthChecksBuilder AddCheck(
            this IHealthChecksBuilder builder,
            string name,
            IHealthCheck instance,
            HealthStatus? failureStatus = null,
            IEnumerable<string>? tags = null,
            TimeSpan? timeout = null)
        {
            if (builder == null)
            {
                throw new ArgumentNullException(nameof(builder));
            }

            if (name == null)
            {
                throw new ArgumentNullException(nameof(name));
            }

            if (instance == null)
            {
                throw new ArgumentNullException(nameof(instance));
            }

            return builder.Add(new HealthCheckRegistration(name, instance, failureStatus, tags, timeout));
        }

此对象随后会在您的健康检查上下文中传递。然后，您可以读取发生故障时预期的 failureStatus，然后从中读取 return 和 HealthCheckResult。在你的情况下，这将 return Degraded :

public class Startup
{
    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }
    public IConfiguration Configuration { get; }
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddHealthChecks().AddCheck<ExampleHealthCheck>("ExampleHealthCheck", failureStatus: HealthStatus.Degraded);
    }
    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        app.UseRouting();
        app.UseEndpoints(endpoints =>
        {
            endpoints.MapHealthChecks("/health");
        });
    }
}

internal class ExampleHealthCheck : IHealthCheck
{
   public Task<HealthCheckResult> CheckHealthAsync(HealthCheckContext context, CancellationToken cancellationToken = default(CancellationToken))
   {
      return Task.FromResult(new HealthCheckResult(context.Registration.FailureStatus));
   }
}

Aspnetcore 健康检查降级状态被忽略

Aspnetcore healthchecks degraded status ignored

c#

asp.net-core

health-check