Add SocketsHttpHandler connection metrics

src/libraries/System.Net.Http/src/System.Net.Http.csproj

@@ -211,6 +211,8 @@
     <Compile Include="System\Net\Http\SocketsHttpHandler\SystemProxyInfo.cs" />
     <Compile Include="System\Net\Http\SocketsHttpHandler\SocksHelper.cs" />
     <Compile Include="System\Net\Http\SocketsHttpHandler\SocksException.cs" />
+    <Compile Include="System\Net\Http\SocketsHttpHandler\Metrics\ConnectionMetrics.cs" />
+    <Compile Include="System\Net\Http\SocketsHttpHandler\Metrics\SocketsHttpHandlerMetrics.cs" />
     <Compile Include="$(CommonPath)System\Net\Security\SslClientAuthenticationOptionsExtensions.cs"
              Link="Common\System\Net\Security\SslClientAuthenticationOptionsExtensions.cs" />
     <Compile Include="$(CommonPath)System\Net\ExceptionCheck.cs"

src/libraries/System.Net.Http/src/System/Net/Http/HttpClientHandler.AnyMobile.cs

@@ -744,7 +744,7 @@ private MetricsHandler SetupHandlerChain()
             {
                 handler = new DiagnosticsHandler(handler, DistributedContextPropagator.Current);
             }
-            MetricsHandler metricsHandler = new MetricsHandler(handler, _meterFactory);
+            MetricsHandler metricsHandler = new MetricsHandler(handler, _meterFactory, out _);
 
             // Ensure a single handler is used for all requests.
             if (Interlocked.CompareExchange(ref _metricsHandler, metricsHandler, null) != null)

src/libraries/System.Net.Http/src/System/Net/Http/HttpClientHandler.cs

@@ -42,7 +42,7 @@ private MetricsHandler Handler
                 {
                     handler = new DiagnosticsHandler(handler, DistributedContextPropagator.Current);
                 }
-                MetricsHandler metricsHandler = new MetricsHandler(handler, _meterFactory);
+                MetricsHandler metricsHandler = new MetricsHandler(handler, _meterFactory, out _);
 
                 // Ensure a single handler is used for all requests.
                 if (Interlocked.CompareExchange(ref _metricsHandler, metricsHandler, null) != null)

src/libraries/System.Net.Http/src/System/Net/Http/Metrics/MetricsHandler.cs

@@ -15,11 +15,11 @@ internal sealed class MetricsHandler : HttpMessageHandlerStage
         private readonly Counter<long> _failedRequests;
         private readonly Histogram<double> _requestsDuration;
 
-        public MetricsHandler(HttpMessageHandler innerHandler, IMeterFactory? meterFactory)
+        public MetricsHandler(HttpMessageHandler innerHandler, IMeterFactory? meterFactory, out Meter meter)
         {
             _innerHandler = innerHandler;
 
-            Meter meter = meterFactory?.Create("System.Net.Http") ?? SharedMeter.Instance;
+            meter = meterFactory?.Create("System.Net.Http") ?? SharedMeter.Instance;
 
             // Meter has a cache for the instruments it owns
             _currentRequests = meter.CreateUpDownCounter<long>(

src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/Http2Connection.cs

@@ -48,7 +48,6 @@ internal sealed partial class Http2Connection : HttpConnectionBase
         private bool _receivedSettingsAck;
         private int _initialServerStreamWindowSize;
         private int _pendingWindowUpdate;
-        private long _idleSinceTickCount;
 
         private uint _maxConcurrentStreams;
         private uint _streamsInUse;
@@ -77,10 +76,6 @@ internal sealed partial class Http2Connection : HttpConnectionBase
         // When all requests have completed, the connection will be torn down.
         private bool _disposed;
 
-        private const int TelemetryStatus_Opened = 1;
-        private const int TelemetryStatus_Closed = 2;
-        private int _markedByTelemetryStatus;
-
         private const int MaxStreamId = int.MaxValue;
 
         // Temporary workaround for request burst handling on connection start.
@@ -138,6 +133,7 @@ internal enum KeepAliveState
         private volatile KeepAliveState _keepAliveState;
 
         public Http2Connection(HttpConnectionPool pool, Stream stream)
+            : base(pool)
         {
             _pool = pool;
             _stream = stream;
@@ -162,7 +158,6 @@ public Http2Connection(HttpConnectionPool pool, Stream stream)
             _streamsInUse = 0;
 
             _pendingWindowUpdate = 0;
-            _idleSinceTickCount = Environment.TickCount64;
 
             _keepAlivePingDelay = TimeSpanToMs(_pool.Settings._keepAlivePingDelay);
             _keepAlivePingTimeout = TimeSpanToMs(_pool.Settings._keepAlivePingTimeout);
@@ -177,12 +172,6 @@ public Http2Connection(HttpConnectionPool pool, Stream stream)
                 _maxHeaderListSize = maxHeaderListSize;
             }
 
-            if (HttpTelemetry.Log.IsEnabled())
-            {
-                HttpTelemetry.Log.Http20ConnectionEstablished();
-                _markedByTelemetryStatus = TelemetryStatus_Opened;
-            }
-
             if (NetEventSource.Log.IsEnabled()) TraceConnection(_stream);
 
             static long TimeSpanToMs(TimeSpan value)
@@ -327,6 +316,11 @@ public bool TryReserveStream()
 
                 if (_streamsInUse < _maxConcurrentStreams)
                 {
+                    if (_streamsInUse == 0)
+                    {
+                        MarkConnectionAsNotIdle();
+                    }
+
                     _streamsInUse++;
                     return true;
                 }
@@ -356,7 +350,7 @@ public void ReleaseStream()
 
                 if (_streamsInUse == 0)
                 {
-                    _idleSinceTickCount = Environment.TickCount64;
+                    MarkConnectionAsIdle();
 
                     if (_disposed)
                     {
@@ -1836,7 +1830,7 @@ public override long GetIdleTicks(long nowTicks)
         {
             lock (SyncObject)
             {
-                return _streamsInUse == 0 ? nowTicks - _idleSinceTickCount : 0;
+                return _streamsInUse == 0 ? base.GetIdleTicks(nowTicks) : 0;
             }
         }
 
@@ -1894,13 +1888,7 @@ private void FinalTeardown()
             // ProcessIncomingFramesAsync and ProcessOutgoingFramesAsync respectively, and those methods are
             // responsible for returning the buffers.
 
-            if (HttpTelemetry.Log.IsEnabled())
-            {
-                if (Interlocked.Exchange(ref _markedByTelemetryStatus, TelemetryStatus_Closed) == TelemetryStatus_Opened)
-                {
-                    HttpTelemetry.Log.Http20ConnectionClosed();
-                }
-            }
+            MarkConnectionAsClosed();
         }
 
         public override void Dispose()

src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/Http3Connection.cs

@@ -11,7 +11,6 @@
 using System.Diagnostics;
 using System.Globalization;
 using System.Net.Http.Headers;
-using System.Net.Security;
 
 namespace System.Net.Http
 {
@@ -21,7 +20,6 @@ namespace System.Net.Http
     internal sealed class Http3Connection : HttpConnectionBase
     {
         private readonly HttpConnectionPool _pool;
-        private readonly HttpAuthority? _origin;
         private readonly HttpAuthority _authority;
         private readonly byte[]? _altUsedEncodedHeader;
         private QuicConnection? _connection;
@@ -48,10 +46,6 @@ internal sealed class Http3Connection : HttpConnectionBase
         // A connection-level error will abort any future operations.
         private Exception? _abortException;
 
-        private const int TelemetryStatus_Opened = 1;
-        private const int TelemetryStatus_Closed = 2;
-        private int _markedByTelemetryStatus;
-
         public HttpAuthority Authority => _authority;
         public HttpConnectionPool Pool => _pool;
         public uint MaxHeaderListSize => _maxHeaderListSize;
@@ -71,10 +65,10 @@ private bool ShuttingDown
             }
         }
 
-        public Http3Connection(HttpConnectionPool pool, HttpAuthority? origin, HttpAuthority authority, QuicConnection connection, bool includeAltUsedHeader)
+        public Http3Connection(HttpConnectionPool pool, HttpAuthority authority, QuicConnection connection, bool includeAltUsedHeader)
+            : base(pool)
         {
             _pool = pool;
-            _origin = origin;
             _authority = authority;
             _connection = connection;
 
@@ -93,12 +87,6 @@ public Http3Connection(HttpConnectionPool pool, HttpAuthority? origin, HttpAutho
                 _maxHeaderListSize = maxHeaderListSize;
             }
 
-            if (HttpTelemetry.Log.IsEnabled())
-            {
-                HttpTelemetry.Log.Http30ConnectionEstablished();
-                _markedByTelemetryStatus = TelemetryStatus_Opened;
-            }
-
             // Errors are observed via Abort().
             _ = SendSettingsAsync();
 
@@ -168,13 +156,7 @@ private void CheckForShutdown()
 
                 }, CancellationToken.None, TaskContinuationOptions.ExecuteSynchronously, TaskScheduler.Default);
 
-                if (HttpTelemetry.Log.IsEnabled())
-                {
-                    if (Interlocked.Exchange(ref _markedByTelemetryStatus, TelemetryStatus_Closed) == TelemetryStatus_Opened)
-                    {
-                        HttpTelemetry.Log.Http30ConnectionClosed();
-                    }
-                }
+                MarkConnectionAsClosed();
             }
         }
 
@@ -201,6 +183,11 @@ public async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, lon
                         requestStream = new Http3RequestStream(request, this, quicStream);
                         lock (SyncObj)
                         {
+                            if (_activeRequests.Count == 0)
+                            {
+                                MarkConnectionAsNotIdle();
+                            }
+
                             _activeRequests.Add(quicStream, requestStream);
                         }
                     }
@@ -352,11 +339,17 @@ public void RemoveStream(QuicStream stream)
         {
             lock (SyncObj)
             {
-                bool removed = _activeRequests.Remove(stream);
-
-                if (removed && ShuttingDown)
+                if (_activeRequests.Remove(stream))
                 {
-                    CheckForShutdown();
+                    if (ShuttingDown)
+                    {
+                        CheckForShutdown();
+                    }
+
+                    if (_activeRequests.Count == 0)
+                    {
+                        MarkConnectionAsIdle();
+                    }
                 }
             }
         }

src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/HttpConnection.cs

@@ -61,7 +61,6 @@ internal sealed partial class HttpConnection : HttpConnectionBase
         private ValueTask<int> _readAheadTask;
         private ArrayBuffer _readBuffer;
 
-        private long _idleSinceTickCount;
         private int _keepAliveTimeoutSeconds; // 0 == no timeout
         private bool _inUse;
         private bool _detachedFromPool;
@@ -70,13 +69,13 @@ internal sealed partial class HttpConnection : HttpConnectionBase
         private bool _connectionClose; // Connection: close was seen on last response
 
         private const int Status_Disposed = 1;
-        private const int Status_NotDisposedAndTrackedByTelemetry = 2;
         private int _disposed;
 
         public HttpConnection(
             HttpConnectionPool pool,
             Stream stream,
             TransportContext? transportContext)
+            : base(pool)
         {
             Debug.Assert(pool != null);
             Debug.Assert(stream != null);
@@ -89,14 +88,6 @@ public HttpConnection(
             _writeBuffer = new ArrayBuffer(InitialWriteBufferSize, usePool: false);
             _readBuffer = new ArrayBuffer(InitialReadBufferSize, usePool: false);
 
-            _idleSinceTickCount = Environment.TickCount64;
-
-            if (HttpTelemetry.Log.IsEnabled())
-            {
-                HttpTelemetry.Log.Http11ConnectionEstablished();
-                _disposed = Status_NotDisposedAndTrackedByTelemetry;
-            }
-
             if (NetEventSource.Log.IsEnabled()) TraceConnection(_stream);
         }
 
@@ -108,16 +99,11 @@ private void Dispose(bool disposing)
         {
             // Ensure we're only disposed once.  Dispose could be called concurrently, for example,
             // if the request and the response were running concurrently and both incurred an exception.
-            int previousValue = Interlocked.Exchange(ref _disposed, Status_Disposed);
-            if (previousValue != Status_Disposed)
+            if (Interlocked.Exchange(ref _disposed, Status_Disposed) != Status_Disposed)
             {
                 if (NetEventSource.Log.IsEnabled()) Trace("Connection closing.");
 
-                // Only decrement the connection count if we counted this connection
-                if (HttpTelemetry.Log.IsEnabled() && previousValue == Status_NotDisposedAndTrackedByTelemetry)
-                {
-                    HttpTelemetry.Log.Http11ConnectionClosed();
-                }
+                MarkConnectionAsClosed();
 
                 if (!_detachedFromPool)
                 {
@@ -270,8 +256,6 @@ private bool CheckKeepAliveTimeoutExceeded()
                 GetIdleTicks(Environment.TickCount64) >= _keepAliveTimeoutSeconds * 1000;
         }
 
-        public override long GetIdleTicks(long nowTicks) => nowTicks - _idleSinceTickCount;
-
         public TransportContext? TransportContext => _transportContext;
 
         public HttpConnectionKind Kind => _pool.Kind;
@@ -517,6 +501,8 @@ public async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, boo
             Debug.Assert(_readBuffer.ActiveLength == 0, "Unexpected data in read buffer");
             Debug.Assert(_readAheadTaskStatus != ReadAheadTask_Started);
 
+            MarkConnectionAsNotIdle();
+
             TaskCompletionSource<bool>? allowExpect100ToContinue = null;
             Task? sendRequestContentTask = null;
 
@@ -2086,8 +2072,6 @@ private void ReturnConnectionToPool()
             {
                 Debug.Assert(!_detachedFromPool, "Should not be detached from pool unless _connectionClose is true");
 
-                _idleSinceTickCount = Environment.TickCount64;
-
                 // Put connection back in the pool.
                 _pool.RecycleHttp11Connection(this);
             }