从 ASP.NET Core 健康检查端点仅获取 HealthCheckResult 中的状态字符串

Question

在我的 ASP.NET Core 应用程序中，我实现了

IHealthCheck

以返回状态

503

，直到应用程序预热完成。但是当我从 Postman 调用此端点时，我在输出中只看到状态字符串，而不是实际的 JSON：

Microsoft.Extensions.Diagnostics.HealthChecks.HealthCheckResult

为什么我没有得到完整的 JSON 响应？我期望一个与此类似的 JSON：

{
   "Status": "Healthy",
   "Description": "The Initialization task has completed."
}

相反，我看到：

健康

附上邮递员提供的以下图片：

IHealthCheck 依赖于另一个对象来获取应用程序预热的状态。根据它返回健康或不健康。

   public class StartupHealthCheck : IHealthCheck
  {
      private volatile bool _isReady;
      private readonly IGlobalState _globalState;
      public StartupHealthCheck(IGlobalState globalState)
          => _globalState = globalState;

  

        public bool StartupCompleted
          {
              get => _isReady;
              set => _isReady = value;
          }
    
          public async Task<HealthCheckResult> CheckHealthAsync(
              HealthCheckContext context, CancellationToken cancellationToken = default)
          {
              if (StartupCompleted && _globalState.PercentageInitialized == 100)
              {
                  return HealthCheckResult.Healthy("The Initialization task has completed.");
              }
    
              return new HealthCheckResult(HealthStatus.Unhealthy, $"The Initialization task is still running at - {_globalState.PercentageInitialized}%.");
          }
      }

Answer 1

您需要在 Program.cs 中自定义输出响应，例如：

static Task WriteResponse(HttpContext context, HealthReport result)
{
    context.Response.ContentType = "application/json; charset=utf-8";
    var options = new JsonWriterOptions
    {
        Indented = true
    };
    using (var stream = new MemoryStream())
    {
        using (var writer = new Utf8JsonWriter(stream, options))
        {
            var healthCheck = result.Entries.FirstOrDefault().Value;
            writer.WriteStartObject();
            writer.WriteString("Status", healthCheck.Status.ToString());
            writer.WriteString("Description", healthCheck.Description);
            writer.WriteEndObject();
        }
        var json = Encoding.UTF8.GetString(stream.ToArray());
        return context.Response.WriteAsync(json);
    }
}

在.NET 6或更高版本中，在Program.cs中注册服务：

builder.Services.AddSingleton<IGlobalState, GlobalState>(); // Assuming IGlobalState is registered

builder.Services.AddHealthChecks()
            .AddCheck<StartupHealthCheck>("startup_health_check");


app.UseEndpoints(endpoints =>
{
    endpoints.MapHealthChecks("/health", new HealthCheckOptions
    {
        ResponseWriter = WriteResponse
    });
});
app.UseAuthorization();    
app.MapControllers();
  
app.Run();

参考：自定义输出