Very simple Metrics.Net integration with ServiceStack

MetricsFeature.cs

    using System;
    using System.Diagnostics;
    using System.Web;
    using metrics;
    using metrics.Core;
    using ServiceStack;

    [Route("/admin/metrics/all")]
    class GetAllMetrics { }
    class MetricsService : IService
    {
        public object Get(GetAllMetrics request)
        {
            return metrics.Metrics.All;
        }
    }

    public class MetricsFeature : IPlugin
    {
        private MeterMetric _requestsMeter = Metrics.Meter(typeof (MetricsFeature), "ServicestackRequests", "requests",
            TimeUnit.Seconds);
        private TimerMetric _requestsTimer = Metrics.Timer(typeof (MetricsFeature), "ServicestackRequestsDuration", TimeUnit.Seconds,
            TimeUnit.Seconds);

        private MeterMetric _errorsMeter = Metrics.Meter(typeof (MetricsFeature), "ServiceStackErrors", "errors",
            TimeUnit.Seconds);

        private class RequestTimer : IDisposable
        {
            private readonly Stopwatch _stopwatch;
            private readonly TimerMetric _metric;

            private RequestTimer(Stopwatch stopwatch, TimerMetric metric)
            {
                _stopwatch = stopwatch;
                _metric = metric;
                _stopwatch.Start();
            }

            public static RequestTimer Start(TimerMetric metric)
            {
                return new RequestTimer(new Stopwatch(), metric);
            }
            public void Dispose()
            {
                _stopwatch.Stop();
                _metric.Update(_stopwatch.ElapsedTicks * 1000000000L / Stopwatch.Frequency, TimeUnit.Nanoseconds);
            }
        }

        public void Register(IAppHost appHost)
        {
            appHost.RegisterService<MetricsService>();   
            appHost.PreRequestFilters.Insert(0, (request, response) =>
            {
                _requestsMeter.Mark();
                ((HttpRequestBase)request.OriginalRequest).RequestContext.HttpContext.Items.Add("_metrics_timer", RequestTimer.Start(_requestsTimer));
            });

            appHost.ServiceExceptionHandlers.Add((req, request, exception) =>
            {
                _errorsMeter.Mark();
                return null;
            });
            appHost.UncaughtExceptionHandlers.Add((req, res, name, exception) => _errorsMeter.Mark());
        }
    }