From 28e4b185a6f13ba84087b53e491d8871b7fd5c1e Mon Sep 17 00:00:00 2001
From: Carlos Neto <carlos.neto@maersk.com>
Date: Mon, 13 Nov 2023 15:07:54 +0000
Subject: [PATCH] Stopping activity as before, and using ticks timestamp to
 compute duration instead of activity durationCalculating the metrics duration
 on the metrics handler instead of stopping asp.net activity

---
 .../ActivityHelper.cs                         |  8 +----
 .../Implementation/HttpInMetricsListener.cs   | 29 ++++++++++++++++---
 2 files changed, 26 insertions(+), 11 deletions(-)

diff --git a/src/OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModule/ActivityHelper.cs b/src/OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModule/ActivityHelper.cs
index fadcd4b7fa..7e66bec332 100644
--- a/src/OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModule/ActivityHelper.cs
+++ b/src/OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModule/ActivityHelper.cs
@@ -133,12 +133,7 @@ public static void StopAspNetActivity(TextMapPropagator textMapPropagator, Activ
         var currentActivity = Activity.Current;
         context.Items[ContextKey] = null;
 
-        // Make sure that the activity has a proper end time before onRequestStoppedCallback is called.
-        // Note that the activity must not be stopped before the callback is called.
-        if (aspNetActivity.Duration == TimeSpan.Zero)
-        {
-            aspNetActivity.SetEndTime(DateTime.UtcNow);
-        }
+        aspNetActivity.Stop();
 
         try
         {
@@ -149,7 +144,6 @@ public static void StopAspNetActivity(TextMapPropagator textMapPropagator, Activ
             AspNetTelemetryEventSource.Log.CallbackException(aspNetActivity, "OnStopped", callbackEx);
         }
 
-        aspNetActivity.Stop();
         AspNetTelemetryEventSource.Log.ActivityStopped(aspNetActivity);
 
         if (textMapPropagator is not TraceContextPropagator)
diff --git a/src/OpenTelemetry.Instrumentation.AspNet/Implementation/HttpInMetricsListener.cs b/src/OpenTelemetry.Instrumentation.AspNet/Implementation/HttpInMetricsListener.cs
index 8ce43d5675..eb7c5e112a 100644
--- a/src/OpenTelemetry.Instrumentation.AspNet/Implementation/HttpInMetricsListener.cs
+++ b/src/OpenTelemetry.Instrumentation.AspNet/Implementation/HttpInMetricsListener.cs
@@ -24,30 +24,41 @@ namespace OpenTelemetry.Instrumentation.AspNet.Implementation;
 
 internal sealed class HttpInMetricsListener : IDisposable
 {
+    private static long syncStopwatchTicks;
     private readonly Histogram<double> httpServerDuration;
     private readonly AspNetMetricsInstrumentationOptions options;
 
     public HttpInMetricsListener(Meter meter, AspNetMetricsInstrumentationOptions options)
     {
         this.httpServerDuration = meter.CreateHistogram<double>("http.server.duration", "ms", "Measures the duration of inbound HTTP requests.");
+        TelemetryHttpModule.Options.OnRequestStartedCallback += this.OnStartActivity;
         TelemetryHttpModule.Options.OnRequestStoppedCallback += this.OnStopActivity;
         this.options = options;
     }
 
     public void Dispose()
     {
+        TelemetryHttpModule.Options.OnRequestStartedCallback -= this.OnStartActivity;
         TelemetryHttpModule.Options.OnRequestStoppedCallback -= this.OnStopActivity;
     }
 
+    private static long TimestampDifference()
+    {
+        return (long)((Stopwatch.GetTimestamp() - syncStopwatchTicks) * 10000000L /
+                                            (double)Stopwatch.Frequency);
+    }
+
+    private void OnStartActivity(Activity activity, HttpContext context)
+    {
+        syncStopwatchTicks = Stopwatch.GetTimestamp();
+    }
+
     private void OnStopActivity(Activity activity, HttpContext context)
     {
-        // TODO: This is just a minimal set of attributes. See the spec for additional attributes:
-        // https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/semantic_conventions/http-metrics.md#http-server
         var tags = new TagList
         {
             { SemanticConventions.AttributeHttpMethod, context.Request.HttpMethod },
             { SemanticConventions.AttributeHttpScheme, context.Request.Url.Scheme },
-            { SemanticConventions.AttributeHttpStatusCode, context.Response.StatusCode },
         };
 
         if (this.options.Enrich is not null)
@@ -62,6 +73,16 @@ private void OnStopActivity(Activity activity, HttpContext context)
             }
         }
 
-        this.httpServerDuration.Record(activity.Duration.TotalMilliseconds, tags);
+        TimeSpan duration = activity.Duration;
+        if (duration == TimeSpan.Zero)
+        {
+            duration = activity.StartTimeUtc.AddTicks(TimestampDifference()) - activity.StartTimeUtc;
+            if (duration.Ticks <= 0)
+            {
+                duration = new TimeSpan(1);
+            }
+        }
+
+        this.httpServerDuration.Record(duration.TotalMilliseconds, tags);
     }
 }