Simple metrics attrinute

DataDogFilterAttribute.cs

    public class DataDogFilterAttribute : ActionFilterAttribute
    {
        const string KEY = nameof(DataDogFilterAttribute) + "Value";

        readonly string _name;

        public DataDogFilterAttribute(string name)
        {
            if (string.IsNullOrEmpty(name))
                throw new ArgumentNullException(nameof(name));
            _name = name;
        }

        private DataDogFilterAttribute()
        {
        }

        public static DataDogFilterAttribute GetGlobalFilter() => new DataDogFilterAttribute();

        public override void OnActionExecuting(HttpActionContext ctx)
        {
            base.OnActionExecuting(ctx);
            ctx.Request.Properties[KEY] = DateTime.Now;
        }

        public override void OnActionExecuted(HttpActionExecutedContext ctx)
        {
            base.OnActionExecuted(ctx);
            var time = DateTime.Now - (DateTime)ctx.Request.Properties[KEY];
            var action = ctx.ActionContext.ActionDescriptor;
            if (string.IsNullOrEmpty(_name) && action.GetCustomAttributes<DataDogFilterAttribute>().Any())
                return;
            var scope = ctx.Request.GetDependencyScope();
            var dataDog = (IDataDogService)scope.GetService(typeof(IDataDogService));
            if (!string.IsNullOrEmpty(_name))
            {
                dataDog.LogMetric(_name, time);
                return;
            }
            var name = GetName(action);
            dataDog.LogMetric(name, time);
        }

        static string GetName(HttpActionDescriptor descriptor) =>
            $"{descriptor.ControllerDescriptor.ControllerName}_{descriptor.ActionName}";
    }

IDataDogService.cs

    public interface IDataDogService
    {
        void LogMetric(string name, TimeSpan value);
    }

RegisterApiFilters.cs

        static void RegisterApiFilters(HttpFilterCollection filters)
        {
            filters.Add(DataDogFilterAttribute.GetGlobalFilter());
        }