Added EventCounters to Hosting

Author: kichalla

src/Microsoft.AspNetCore.Hosting/Internal/HostingApplication.cs

@@ -42,18 +42,20 @@ public Context CreateContext(IFeatureCollection contextFeatures)
         {
             var httpContext = _httpContextFactory.Create(contextFeatures);
 
+            var eventLogEnabled = HostingEventSource.Log.IsEnabled();
+
             // These enabled checks are virtual dispatch and used twice and so cache to locals
             var diagnoticsEnabled = _diagnosticSource.IsEnabled(DiagnosticsBeginRequestKey);
             var loggingEnabled = _logger.IsEnabled(LogLevel.Information);
 
-            if (HostingEventSource.Log.IsEnabled())
+            if (eventLogEnabled)
             {
                 // To keep the hot path short we defer logging in this function to non-inlines
                 RecordRequestStartEventLog(httpContext);
             }
 
             // Only make call GetTimestamp if its value will be used, i.e. of the listenters is enabled
-            var startTimestamp = (diagnoticsEnabled || loggingEnabled) ? Stopwatch.GetTimestamp() : 0;
+            var startTimestamp = (diagnoticsEnabled || loggingEnabled || eventLogEnabled) ? Stopwatch.GetTimestamp() : 0;
 
             // Scope may be relevant for a different level of logging, so we always create it
             // see: https://github.com/aspnet/Hosting/pull/944
@@ -107,7 +109,7 @@ public void DisposeContext(Context context, Exception exception)
                     // Diagnostics is enabled for EndRequest, but it may not be for BeginRequest
                     // so call GetTimestamp if currentTimestamp is zero (from above)
                     RecordEndRequestDiagnostics(
-                        httpContext, 
+                        httpContext,
                         (currentTimestamp != 0) ? currentTimestamp : Stopwatch.GetTimestamp());
                 }
             }
@@ -119,8 +121,8 @@ public void DisposeContext(Context context, Exception exception)
                     // Diagnostics is enabled for UnhandledException, but it may not be for BeginRequest 
                     // so call GetTimestamp if currentTimestamp is zero (from above)
                     RecordUnhandledExceptionDiagnostics(
-                        httpContext, 
-                        (currentTimestamp != 0) ? currentTimestamp : Stopwatch.GetTimestamp(), 
+                        httpContext,
+                        (currentTimestamp != 0) ? currentTimestamp : Stopwatch.GetTimestamp(),
                         exception);
                 }
 
@@ -146,7 +148,7 @@ public void DisposeContext(Context context, Exception exception)
             if (eventLogEnabled)
             {
                 // Non-inline
-                hostingEventLog.RequestStop();
+                hostingEventLog.RequestStop(startTimestamp, currentTimestamp);
             }
         }
 

src/Microsoft.AspNetCore.Hosting/Internal/HostingEventSource.cs

@@ -11,7 +11,22 @@ public sealed class HostingEventSource : EventSource
     {
         public static readonly HostingEventSource Log = new HostingEventSource();
 
-        private HostingEventSource() { }
+#if NETSTANDARD1_5
+        private EventCounter _requestCounter = null;
+        private EventCounter _successfulRequestCounter = null;
+        private EventCounter _failedRequestCounter = null;
+        private EventCounter _requestExecutionTimeCounter = null;
+#endif
+
+        private HostingEventSource()
+        {
+#if NETSTANDARD1_5
+            _requestCounter = new EventCounter("Request", this);
+            _successfulRequestCounter = new EventCounter("SuccessfulRequest", this);
+            _failedRequestCounter = new EventCounter("FailedRequest", this);
+            _requestExecutionTimeCounter = new EventCounter("RequestExecutionTime", this);
+#endif
+        }
 
         // NOTE
         // - The 'Start' and 'Stop' suffixes on the following event names have special meaning in EventSource. They
@@ -35,12 +50,29 @@ public void HostStop()
         [Event(3, Level = EventLevel.Informational)]
         public void RequestStart(string method, string path)
         {
+#if NETSTANDARD1_5
+            _requestCounter.WriteMetric(1);
+#endif
             WriteEvent(3, method, path);
         }
 
         [MethodImpl(MethodImplOptions.NoInlining)]
+        [NonEvent]
+        public void RequestStop(long startTimestamp, long endTimestamp)
+        {
+#if NETSTANDARD1_5
+            _successfulRequestCounter.WriteMetric(1);
+
+            if (endTimestamp != 0)
+            {
+                _requestExecutionTimeCounter.WriteMetric(endTimestamp - startTimestamp);
+            }
+#endif
+            RequestStop();
+        }
+
         [Event(4, Level = EventLevel.Informational)]
-        public void RequestStop()
+        private void RequestStop()
         {
             WriteEvent(4);
         }
@@ -49,7 +81,11 @@ public void RequestStop()
         [Event(5, Level = EventLevel.Error)]
         public void UnhandledException()
         {
+#if NETSTANDARD1_5
+            _failedRequestCounter.WriteMetric(1);
+#endif
             WriteEvent(5);
         }
+
     }
-}
+}

src/Microsoft.AspNetCore.Hosting/Internal/WebHost.cs

@@ -70,6 +70,10 @@ public WebHost(
             _hostingServiceProvider = hostingServiceProvider;
             _applicationServiceCollection.AddSingleton<IApplicationLifetime, ApplicationLifetime>();
             _applicationServiceCollection.AddSingleton<HostedServiceExecutor>();
+
+            // This is here for the sole reason to load it as fast as possible in the application domain and be found
+            // by the EventSource.GetSources() api.
+            var eventSource = HostingEventSource.Log;
         }
 
         public IServiceProvider Services

test/Microsoft.AspNetCore.Hosting.Tests/Internal/HostingEventSourceTests.cs

@@ -151,7 +151,7 @@ public void RequestStop()
             eventListener.EnableEvents(hostingEventSource, EventLevel.Informational);
 
             // Act
-            hostingEventSource.RequestStop();
+            hostingEventSource.RequestStop(startTimestamp: 0, endTimestamp: 0);
 
             // Assert
             var eventData = eventListener.EventData;