Create KestrelEventSource

Adds an EventSource for Kestrel named 'Microsoft-AspNetCore-Server-Kestrel' with the following event and properties:

ConnectionStart:
 - connectionId
 - serverAddress
 - localEndPoint
 - remoteEndPoint

 Resolves #1211

Author: Nate McMaster

.gitignore

@@ -32,3 +32,4 @@ runtimes/
 launchSettings.json
 BenchmarkDotNet.Artifacts/
 BDN.Generated/
+.idea/

src/Microsoft.AspNetCore.Server.Kestrel/Internal/Http/Connection.cs

@@ -85,6 +85,7 @@ internal Connection()
         public void Start()
         {
             Log.ConnectionStart(ConnectionId);
+            KestrelEventSource.Log.ConnectionStart(this);
 
             // Start socket prior to applying the ConnectionFilter
             _socket.ReadStart(_allocCallback, _readCallback, this);

src/Microsoft.AspNetCore.Server.Kestrel/Internal/Infrastructure/KestrelEventSource.cs

@@ -0,0 +1,46 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Diagnostics.Tracing;
+using Microsoft.AspNetCore.Server.Kestrel.Internal.Http;
+
+namespace Microsoft.AspNetCore.Server.Kestrel.Internal.Infrastructure
+{
+    [EventSource(Name = "Microsoft-AspNetCore-Server-Kestrel")]
+    public sealed class KestrelEventSource : EventSource
+    {
+        public static readonly KestrelEventSource Log = new KestrelEventSource();
+
+        private KestrelEventSource()
+        {
+        }
+
+        [NonEvent]
+        public void ConnectionStart(Connection connection)
+        {
+            if (IsEnabled())
+            {
+                ConnectionStart(
+                    connection.ConnectionId,
+                    connection.ListenerContext.ServerAddress.ToString(),
+                    connection.RemoteEndPoint.ToString(),
+                    connection.LocalEndPoint.ToString());
+            }
+        }
+
+        [Event(1, Level = EventLevel.Informational)]
+        private void ConnectionStart(string connectionId,
+            string serverAddress,
+            string remoteEndPoint,
+            string localEndPoint)
+        {
+            WriteEvent(
+                1,
+                connectionId,
+                serverAddress,
+                remoteEndPoint,
+                localEndPoint
+            );
+        }
+    }
+}

test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/EventSourceTests.cs

@@ -0,0 +1,83 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.Tracing;
+using System.Linq;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Http.Features;
+using Microsoft.AspNetCore.Server.Kestrel.Internal.Infrastructure;
+using Microsoft.AspNetCore.Testing;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
+{
+    public class EventSourceTests
+    {
+        [Fact]
+        public async Task LogsConnection()
+        {
+            var listener = new TestEventListener();
+            listener.EnableEvents(KestrelEventSource.Log, EventLevel.Informational);
+
+            var host = new WebHostBuilder()
+                .UseUrls("http://127.0.0.1:0")
+                .UseKestrel()
+                .Configure(app =>
+                {
+                    app.Run(context =>
+                    {
+                        var id = context.Features.Get<IHttpConnectionFeature>().ConnectionId;
+                        context.Response.ContentLength = id.Length;
+                        return context.Response.WriteAsync(id);
+                    });
+                })
+                .Build();
+
+            string connectionId;
+            using (host)
+            {
+                host.Start();
+
+                connectionId = await HttpClientSlim.GetStringAsync($"http://127.0.0.1:{host.GetPort()}/")
+                    .TimeoutAfter(TimeSpan.FromSeconds(10));
+            }
+
+            // capture list here as other tests executing in parallel may log events
+            var events = listener.EventData.ToList();
+#if NET451
+            // collection may contain connection events from other tests
+            var start = Assert.Single(listener.EventData, e => (e.Payload.FirstOrDefault() as string) == connectionId);
+#else
+            var start = Assert.Single(listener.EventData, e => GetProperty(e, "connectionId") == connectionId);
+            Assert.Equal("ConnectionStart", start.EventName);
+            Assert.All(new[] {"serverAddress", "connectionId", "remoteEndPoint", "localEndPoint"},
+                p => Assert.Contains(p, start.PayloadNames));
+            Assert.Equal($"http://127.0.0.1:{host.GetPort()}", GetProperty(start, "serverAddress"));
+            Assert.Equal(connectionId, GetProperty(start, "connectionId"));
+#endif
+            Assert.Same(KestrelEventSource.Log, start.EventSource);
+        }
+
+#if !NET451
+        private string GetProperty(EventWrittenEventArgs data, string propName)
+            => data.Payload[data.PayloadNames.IndexOf(propName)] as string;
+#endif
+
+        private class TestEventListener : EventListener
+        {
+            private List<EventWrittenEventArgs> _events = new List<EventWrittenEventArgs>();
+            
+            public IEnumerable<EventWrittenEventArgs> EventData => _events;
+
+            protected override void OnEventWritten(EventWrittenEventArgs eventData)
+            {
+                _events.Add(eventData);
+            }
+        }
+    }
+}

test/Microsoft.AspNetCore.Server.KestrelTests/KestrelEventSourceTests.cs

@@ -0,0 +1,30 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Diagnostics.Tracing;
+using System.Reflection;
+using Microsoft.AspNetCore.Server.Kestrel;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Server.KestrelTests
+{
+    public class KestrelEventSourceTests
+    {
+        [Fact]
+        public void ExistsWithCorrectId()
+        {
+            var esType = typeof(KestrelServer).GetTypeInfo().Assembly.GetType(
+                "Microsoft.AspNetCore.Server.Kestrel.Internal.Infrastructure.KestrelEventSource",
+                throwOnError: true,
+                ignoreCase: false
+            );
+
+            Assert.NotNull(esType);
+
+            Assert.Equal("Microsoft-AspNetCore-Server-Kestrel", EventSource.GetName(esType));
+            Assert.Equal(Guid.Parse("bdeb4676-a36e-5442-db99-4764e2326c7d"), EventSource.GetGuid(esType));
+            Assert.NotEmpty(EventSource.GenerateManifest(esType, "assemblyPathToIncludeInManifest"));
+        }
+    }
+}