Adjust System.Net.Http metrics

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

@@ -176,7 +176,7 @@ internal static HttpMethod Normalize(HttpMethod method)
                 method;
         }
 
-        private static HttpMethod? GetKnownMethod(ReadOnlySpan<char> method)
+        internal static HttpMethod? GetKnownMethod(ReadOnlySpan<char> method)
         {
             if (method.Length >= 3) // 3 == smallest known method
             {

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

@@ -108,15 +108,12 @@ public static void AddCallback(HttpRequestMessage request, Action<HttpMetricsEnr
             return context;
         }
 
-        internal void RecordWithEnrichment(HttpRequestMessage request,
+        internal void RecordDurationWithEnrichment(HttpRequestMessage request,
             HttpResponseMessage? response,
             Exception? exception,
-            long startTimestamp,
+            TimeSpan durationTime,
             in TagList commonTags,
-            bool recordRequestDuration,
-            bool recordFailedRequests,
-            Histogram<double> requestDuration,
-            Counter<long> failedRequests)
+            Histogram<double> requestDuration)
         {
             _request = request;
             _response = response;
@@ -140,16 +137,7 @@ internal void RecordWithEnrichment(HttpRequestMessage request,
                     callback(this);
                 }
 
-                if (recordRequestDuration)
-                {
-                    TimeSpan duration = Stopwatch.GetElapsedTime(startTimestamp, Stopwatch.GetTimestamp());
-                    requestDuration.Record(duration.TotalSeconds, CollectionsMarshal.AsSpan(_tags));
-                }
-
-                if (recordFailedRequests)
-                {
-                    failedRequests.Add(1, CollectionsMarshal.AsSpan(_tags));
-                }
+                requestDuration.Record(durationTime.TotalSeconds, CollectionsMarshal.AsSpan(_tags));
             }
             finally
             {

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

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Collections.Generic;
 using System.Diagnostics;
 using System.Diagnostics.Metrics;
 using System.Threading;
@@ -11,8 +12,7 @@ namespace System.Net.Http.Metrics
     internal sealed class MetricsHandler : HttpMessageHandlerStage
     {
         private readonly HttpMessageHandler _innerHandler;
-        private readonly UpDownCounter<long> _currentRequests;
-        private readonly Counter<long> _failedRequests;
+        private readonly UpDownCounter<long> _activeRequests;
         private readonly Histogram<double> _requestsDuration;
 
         public MetricsHandler(HttpMessageHandler innerHandler, IMeterFactory? meterFactory, out Meter meter)
@@ -22,21 +22,18 @@ public MetricsHandler(HttpMessageHandler innerHandler, IMeterFactory? meterFacto
             meter = meterFactory?.Create("System.Net.Http") ?? SharedMeter.Instance;
 
             // Meter has a cache for the instruments it owns
-            _currentRequests = meter.CreateUpDownCounter<long>(
-                "http-client-current-requests",
+            _activeRequests = meter.CreateUpDownCounter<long>(
+                "http.client.active_requests",
                 description: "Number of outbound HTTP requests that are currently active on the client.");
-            _failedRequests = meter.CreateCounter<long>(
-                "http-client-failed-requests",
-                description: "Number of outbound HTTP requests that have failed.");
             _requestsDuration = meter.CreateHistogram<double>(
-                "http-client-request-duration",
+                "http.client.request.duration",
                 unit: "s",
                 description: "The duration of outbound HTTP requests.");
         }
 
         internal override ValueTask<HttpResponseMessage> SendAsync(HttpRequestMessage request, bool async, CancellationToken cancellationToken)
         {
-            if (_currentRequests.Enabled || _failedRequests.Enabled || _requestsDuration.Enabled)
+            if (_activeRequests.Enabled || _requestsDuration.Enabled)
             {
                 return SendAsyncWithMetrics(request, async, cancellationToken);
             }
@@ -83,13 +80,13 @@ protected override void Dispose(bool disposing)
 
         private (long StartTimestamp, bool RecordCurrentRequests) RequestStart(HttpRequestMessage request)
         {
-            bool recordCurrentRequests = _currentRequests.Enabled;
+            bool recordCurrentRequests = _activeRequests.Enabled;
             long startTimestamp = Stopwatch.GetTimestamp();
 
             if (recordCurrentRequests)
             {
                 TagList tags = InitializeCommonTags(request);
-                _currentRequests.Add(1, tags);
+                _activeRequests.Add(1, tags);
             }
 
             return (startTimestamp, recordCurrentRequests);
@@ -101,49 +98,71 @@ private void RequestStop(HttpRequestMessage request, HttpResponseMessage? respon
 
             if (recordCurrentRequsts)
             {
-                _currentRequests.Add(-1, tags);
+                _activeRequests.Add(-1, tags);
             }
 
-            bool recordRequestDuration = _requestsDuration.Enabled;
-            bool recordFailedRequests = _failedRequests.Enabled && response is null;
+            if (!_requestsDuration.Enabled)
+            {
+                return;
+            }
 
-            HttpMetricsEnrichmentContext? enrichmentContext = null;
-            if (recordRequestDuration || recordFailedRequests)
+            if (response is not null)
             {
-                if (response is not null)
-                {
-                    tags.Add("status-code", GetBoxedStatusCode((int)response.StatusCode));
-                    tags.Add("protocol", GetProtocolName(response.Version));
-                }
-                enrichmentContext = HttpMetricsEnrichmentContext.GetEnrichmentContextForRequest(request);
+                tags.Add("http.response.status_code", GetBoxedStatusCode((int)response.StatusCode));
+                tags.Add("network.protocol.version", GetProtocolVersionString(response.Version));
+            }
+            else
+            {
+                Debug.Assert(exception is not null);
+                tags.Add("http.error.reason", GetErrorReason(exception));
             }
+            TimeSpan durationTime = Stopwatch.GetElapsedTime(startTimestamp, Stopwatch.GetTimestamp());
 
+            HttpMetricsEnrichmentContext? enrichmentContext = HttpMetricsEnrichmentContext.GetEnrichmentContextForRequest(request);
             if (enrichmentContext is null)
             {
-                if (recordRequestDuration)
-                {
-                    TimeSpan duration = Stopwatch.GetElapsedTime(startTimestamp, Stopwatch.GetTimestamp());
-                    _requestsDuration.Record(duration.TotalSeconds, tags);
-                }
-
-                if (recordFailedRequests)
-                {
-                    _failedRequests.Add(1, tags);
-                }
+                _requestsDuration.Record(durationTime.TotalSeconds, tags);
             }
             else
             {
-                enrichmentContext.RecordWithEnrichment(request, response, exception, startTimestamp, tags, recordRequestDuration, recordFailedRequests, _requestsDuration, _failedRequests);
+                enrichmentContext.RecordDurationWithEnrichment(request, response, exception, durationTime, tags, _requestsDuration);
             }
         }
 
-        private static string GetProtocolName(Version httpVersion) => (httpVersion.Major, httpVersion.Minor) switch
+        private static string GetErrorReason(Exception exception)
         {
-            (1, 0) => "HTTP/1.0",
-            (1, 1) => "HTTP/1.1",
-            (2, 0) => "HTTP/2",
-            (3, 0) => "HTTP/3",
-            _ => $"HTTP/{httpVersion.Major}.{httpVersion.Minor}"
+            if (exception is OperationCanceledException)
+            {
+                return "cancellation";
+            }
+            else if (exception is HttpRequestException e)
+            {
+                return e.HttpRequestError switch
+                {
+                    HttpRequestError.NameResolutionError => "name_resolution_error",
+                    HttpRequestError.ConnectionError => "connection_error",
+                    HttpRequestError.SecureConnectionError => "secure_connection_error",
+                    HttpRequestError.HttpProtocolError => "http_protocol_error",
+                    HttpRequestError.ExtendedConnectNotSupported => "extended_connect_not_supported",
+                    HttpRequestError.VersionNegotiationError => "version_negotiation_error",
+                    HttpRequestError.UserAuthenticationError => "user_authentication_error",
+                    HttpRequestError.ProxyTunnelError => "proxy_tunnel_error",
+                    HttpRequestError.InvalidResponse => "invalid_response",
+                    HttpRequestError.ResponseEnded => "response_ended",
+                    HttpRequestError.ConfigurationLimitExceeded => "configuration_limit_exceeded",
+                    _ => "_OTHER"
+                };
+            }
+            return "_OTHER";
+        }
+
+        private static string GetProtocolVersionString(Version httpVersion) => (httpVersion.Major, httpVersion.Minor) switch
+        {
+            (1, 0) => "1.0",
+            (1, 1) => "1.1",
+            (2, 0) => "2.0",
+            (3, 0) => "3.0",
+            _ => httpVersion.ToString()
         };
 
         private static TagList InitializeCommonTags(HttpRequestMessage request)
@@ -152,19 +171,26 @@ private static TagList InitializeCommonTags(HttpRequestMessage request)
 
             if (request.RequestUri is Uri requestUri && requestUri.IsAbsoluteUri)
             {
-                tags.Add("scheme", requestUri.Scheme);
-                tags.Add("host", requestUri.Host);
+                tags.Add("url.scheme", requestUri.Scheme);
+                tags.Add("server.address", requestUri.Host);
                 // Add port tag when not the default value for the current scheme
                 if (!requestUri.IsDefaultPort)
                 {
-                    tags.Add("port", requestUri.Port);
+                    tags.Add("server.port", requestUri.Port);
                 }
             }
-            tags.Add("method", request.Method.Method);
+            tags.Add(GetMethodTag(request.Method));
 
             return tags;
         }
 
+        internal static KeyValuePair<string, object?> GetMethodTag(HttpMethod method)
+        {
+            // The OTel spec requires us to return canonical names for known methods and "_OTHER" for unknown ones.
+            HttpMethod? known = HttpMethod.GetKnownMethod(method.Method);
+            return new KeyValuePair<string, object?>("http.request.method", known?.Method ?? "_OTHER");
+        }
+
         private static object[]? s_boxedStatusCodes;
 
         private static object GetBoxedStatusCode(int statusCode)

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

@@ -197,7 +197,7 @@ public async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, lon
                     {
                         TimeSpan duration = Stopwatch.GetElapsedTime(queueStartingTimestamp);
 
-                        _pool.Settings._metrics!.RequestLeftQueue(Pool, duration, versionMajor: 3);
+                        _pool.Settings._metrics!.RequestLeftQueue(request, Pool, duration, versionMajor: 3);
 
                         if (HttpTelemetry.Log.IsEnabled())
                         {

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

@@ -42,26 +42,24 @@ public HttpConnectionBase(HttpConnectionPool pool, IPEndPoint? remoteEndPoint)
 
             SocketsHttpHandlerMetrics metrics = pool.Settings._metrics;
 
-            if (metrics.CurrentConnections.Enabled ||
-                metrics.IdleConnections.Enabled ||
-                metrics.ConnectionDuration.Enabled)
+            if (metrics.OpenConnections.Enabled || metrics.ConnectionDuration.Enabled)
             {
                 // While requests may report HTTP/1.0 as the protocol, we treat all HTTP/1.X connections as HTTP/1.1.
                 string protocol =
-                    this is HttpConnection ? "HTTP/1.1" :
-                    this is Http2Connection ? "HTTP/2" :
-                    "HTTP/3";
+                    this is HttpConnection ? "1.1" :
+                    this is Http2Connection ? "2.0" :
+                    "3.0";
 
                 _connectionMetrics = new ConnectionMetrics(
                     metrics,
                     protocol,
                     pool.IsSecure ? "https" : "http",
                     pool.OriginAuthority.HostValue,
-                    pool.IsDefaultPort ? null : pool.OriginAuthority.Port);
+                    pool.IsDefaultPort ? null : pool.OriginAuthority.Port,
+                    remoteEndPoint?.Address?.ToString());
 
                 _connectionMetrics.ConnectionEstablished();
-
-                MarkConnectionAsIdle();
+                _idleSinceTickCount = Environment.TickCount64;
             }
 
             if (HttpTelemetry.Log.IsEnabled())
@@ -97,13 +95,12 @@ public void MarkConnectionAsClosed()
         public void MarkConnectionAsIdle()
         {
             _idleSinceTickCount = Environment.TickCount64;
-
-            _connectionMetrics?.MarkAsIdle();
+            _connectionMetrics?.IdleStateChanged(idle: true);
         }
 
         public void MarkConnectionAsNotIdle()
         {
-            _connectionMetrics?.MarkAsNotIdle();
+            _connectionMetrics?.IdleStateChanged(idle: false);
         }
 
         /// <summary>Uses <see cref="HeaderDescriptor.GetHeaderValue"/>, but first special-cases several known headers for which we can use caching.</summary>

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

@@ -1084,7 +1084,7 @@ public async ValueTask<HttpResponseMessage> SendWithVersionDetectionAndRetryAsyn
                             if (!TryGetPooledHttp2Connection(request, out Http2Connection? connection, out http2ConnectionWaiter) &&
                                 http2ConnectionWaiter != null)
                             {
-                                connection = await http2ConnectionWaiter.WaitForConnectionAsync(this, async, cancellationToken).ConfigureAwait(false);
+                                connection = await http2ConnectionWaiter.WaitForConnectionAsync(request, this, async, cancellationToken).ConfigureAwait(false);
                             }
 
                             Debug.Assert(connection is not null || !_http2Enabled);
@@ -1116,7 +1116,7 @@ public async ValueTask<HttpResponseMessage> SendWithVersionDetectionAndRetryAsyn
                             // Use HTTP/1.x.
                             if (!TryGetPooledHttp11Connection(request, async, out HttpConnection? connection, out http11ConnectionWaiter))
                             {
-                                connection = await http11ConnectionWaiter.WaitForConnectionAsync(this, async, cancellationToken).ConfigureAwait(false);
+                                connection = await http11ConnectionWaiter.WaitForConnectionAsync(request, this, async, cancellationToken).ConfigureAwait(false);
                             }
 
                             connection.Acquire(); // In case we are doing Windows (i.e. connection-based) auth, we need to ensure that we hold on to this specific connection while auth is underway.
@@ -2620,14 +2620,14 @@ private sealed class HttpConnectionWaiter<T> : TaskCompletionSourceWithCancellat
             // Distinguish connection cancellation that happens because the initiating request is cancelled or completed on a different connection.
             public bool CancelledByOriginatingRequestCompletion { get; set; }
 
-            public ValueTask<T> WaitForConnectionAsync(HttpConnectionPool pool, bool async, CancellationToken requestCancellationToken)
+            public ValueTask<T> WaitForConnectionAsync(HttpRequestMessage request, HttpConnectionPool pool, bool async, CancellationToken requestCancellationToken)
             {
                 return HttpTelemetry.Log.IsEnabled() || pool.Settings._metrics!.RequestsQueueDuration.Enabled
-                    ? WaitForConnectionWithTelemetryAsync(pool, async, requestCancellationToken)
+                    ? WaitForConnectionWithTelemetryAsync(request, pool, async, requestCancellationToken)
                     : WaitWithCancellationAsync(async, requestCancellationToken);
             }
 
-            private async ValueTask<T> WaitForConnectionWithTelemetryAsync(HttpConnectionPool pool, bool async, CancellationToken requestCancellationToken)
+            private async ValueTask<T> WaitForConnectionWithTelemetryAsync(HttpRequestMessage request, HttpConnectionPool pool, bool async, CancellationToken requestCancellationToken)
             {
                 Debug.Assert(typeof(T) == typeof(HttpConnection) || typeof(T) == typeof(Http2Connection));
 
@@ -2641,7 +2641,7 @@ private async ValueTask<T> WaitForConnectionWithTelemetryAsync(HttpConnectionPoo
                     TimeSpan duration = Stopwatch.GetElapsedTime(startingTimestamp);
                     int versionMajor = typeof(T) == typeof(HttpConnection) ? 1 : 2;
 
-                    pool.Settings._metrics!.RequestLeftQueue(pool, duration, versionMajor);
+                    pool.Settings._metrics!.RequestLeftQueue(request, pool, duration, versionMajor);
 
                     if (HttpTelemetry.Log.IsEnabled())
                     {