[Feature] Add OTel support

.github/workflows/dotnet.yml

@@ -65,6 +65,7 @@ jobs:
               dotnet pack "src\Discord.Net.Commands\Discord.Net.Commands.csproj" --no-restore --no-build -v minimal -c Release -o ${{ env.ArtifactStagingDirectory }} /p:BuildNumber=${{ env.Suffix }} /p:IsTagBuild=${{ env.IsTagBuild }}
               dotnet pack "src\Discord.Net.Webhook\Discord.Net.Webhook.csproj" --no-restore --no-build -v minimal -c Release -o ${{ env.ArtifactStagingDirectory }} /p:BuildNumber=${{ env.Suffix }} /p:IsTagBuild=${{ env.IsTagBuild }}
               dotnet pack "src\Discord.Net.Interactions\Discord.Net.Interactions.csproj" --no-restore --no-build -v minimal -c Release -o ${{ env.ArtifactStagingDirectory }} /p:BuildNumber=${{ env.Suffix }} /p:IsTagBuild=${{ env.IsTagBuild }}
+              dotnet pack "src\Discord.Net.OpenTelemetry\Discord.Net.OpenTelemetry.csproj" --no-restore --no-build -v minimal -c Release -o ${{ env.ArtifactStagingDirectory }} /p:BuildNumber=${{ env.Suffix }} /p:IsTagBuild=${{ env.IsTagBuild }}
 #              dotnet pack "experiment\Discord.Net.BuildOverrides\Discord.Net.BuildOverrides.csproj" --no-restore --no-build -v minimal -c Release -o ${{ env.ArtifactStagingDirectory }} /p:BuildNumber=${{ env.Suffix }} /p:IsTagBuild=${{ env.IsTagBuild }}
 
           - name: Publish Artifacts

Discord.Net.sln

@@ -42,6 +42,8 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Samples", "Samples", "{BB59
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Discord.Net.BuildOverrides", "experiment\Discord.Net.BuildOverrides\Discord.Net.BuildOverrides.csproj", "{115F4921-B44D-4F69-996B-69796959C99D}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Discord.Net.OpenTelemetry", "src\Discord.Net.OpenTelemetry\Discord.Net.OpenTelemetry.csproj", "{88D77C2C-547E-41B8-8AFC-D1C089652767}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -244,6 +246,18 @@ Global
 		{115F4921-B44D-4F69-996B-69796959C99D}.Release|x64.Build.0 = Release|Any CPU
 		{115F4921-B44D-4F69-996B-69796959C99D}.Release|x86.ActiveCfg = Release|Any CPU
 		{115F4921-B44D-4F69-996B-69796959C99D}.Release|x86.Build.0 = Release|Any CPU
+		{88D77C2C-547E-41B8-8AFC-D1C089652767}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{88D77C2C-547E-41B8-8AFC-D1C089652767}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{88D77C2C-547E-41B8-8AFC-D1C089652767}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{88D77C2C-547E-41B8-8AFC-D1C089652767}.Debug|x64.Build.0 = Debug|Any CPU
+		{88D77C2C-547E-41B8-8AFC-D1C089652767}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{88D77C2C-547E-41B8-8AFC-D1C089652767}.Debug|x86.Build.0 = Debug|Any CPU
+		{88D77C2C-547E-41B8-8AFC-D1C089652767}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{88D77C2C-547E-41B8-8AFC-D1C089652767}.Release|Any CPU.Build.0 = Release|Any CPU
+		{88D77C2C-547E-41B8-8AFC-D1C089652767}.Release|x64.ActiveCfg = Release|Any CPU
+		{88D77C2C-547E-41B8-8AFC-D1C089652767}.Release|x64.Build.0 = Release|Any CPU
+		{88D77C2C-547E-41B8-8AFC-D1C089652767}.Release|x86.ActiveCfg = Release|Any CPU
+		{88D77C2C-547E-41B8-8AFC-D1C089652767}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -264,6 +278,7 @@ Global
 		{B61AAE66-15CC-40E4-873A-C23E697C3411} = {BB59D5B5-E7B0-4BF4-8F82-D14431B2799B}
 		{4A03840B-9EBE-47E3-89AB-E0914DF21AFB} = {BB59D5B5-E7B0-4BF4-8F82-D14431B2799B}
 		{115F4921-B44D-4F69-996B-69796959C99D} = {CC3D4B1C-9DE0-448B-8AE7-F3F1F3EC5C3A}
+		{88D77C2C-547E-41B8-8AFC-D1C089652767} = {CC3D4B1C-9DE0-448B-8AE7-F3F1F3EC5C3A}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {D2404771-EEC8-45F2-9D71-F3373F6C1495}

src/Discord.Net.OpenTelemetry/Discord.Net.OpenTelemetry.csproj

@@ -0,0 +1,22 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <Import Project="../../Discord.Net.targets" />
+  <Import Project="../../StyleAnalyzer.targets" />
+  <PropertyGroup>
+    <TargetFrameworks>net9.0;net8.0;net6.0;net5.0;net461;netstandard2.0;netstandard2.1</TargetFrameworks>
+    <RootNamespace>Discord.OpenTelemetry</RootNamespace>
+    <AssemblyName>Discord.Net.OpenTelemetry</AssemblyName>
+    <Description>A Discord.Net extension adding support for the OpenTelemetry (otel) Sdk.</Description>
+    <WarningLevel>5</WarningLevel>
+    <TreatWarningsAsErrors>True</TreatWarningsAsErrors>
+    <IncludeSymbols>true</IncludeSymbols>
+    <SymbolPackageFormat>snupkg</SymbolPackageFormat>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="OpenTelemetry.Api.ProviderBuilderExtensions" Version="1.11.2" />
+  </ItemGroup>
+  <ItemGroup Condition="$(TargetFramework.StartsWith('net4')) AND '$(MSBuildRuntimeType)' == 'Core'">
+    <PackageReference Include="Microsoft.NETFramework.ReferenceAssemblies" Version="1.0.3" PrivateAssets="All" />
+  </ItemGroup>
+
+</Project>

src/Discord.Net.OpenTelemetry/Extensions.cs

@@ -0,0 +1,41 @@
+using OpenTelemetry.Metrics;
+using OpenTelemetry.Trace;
+using System;
+
+namespace Discord.OpenTelemetry
+{
+    /// <summary>
+    /// An extension class which contains methods to add the Discord.Net OpenTelemetry instrumentation.
+    /// </summary>
+    public static class Extensions
+    {
+        private static readonly string[] _sourceNames = ["Discord.Net.WebSocket", "Discord.Net.Audio"];
+
+        /// <summary>
+        /// Adds the trace sources of DNet.
+        /// </summary>
+        /// <param name="builder">The trace provider to add these sources to.</param>
+        /// <returns>The provided trace provider to chain calls.</returns>
+        /// <exception cref="ArgumentNullException"></exception>
+        public static TracerProviderBuilder AddDiscordNetInstrumentation(this TracerProviderBuilder builder)
+        {
+            if (builder is null)
+                throw new ArgumentNullException(nameof(builder));
+            return builder.AddSource(_sourceNames);
+        }
+
+        /// <summary>
+        /// Adds the meters of DNet.
+        /// </summary>
+        /// <param name="builder">The meter provider to add the meters to.</param>
+        /// <returns>The provided meter builder to chain calls.</returns>
+        /// <exception cref="ArgumentNullException"></exception>
+        public static MeterProviderBuilder AddDiscordNetInstrumentation(this MeterProviderBuilder builder)
+        {
+            if (builder is null)
+                throw new ArgumentNullException(nameof(builder));
+            return builder.AddMeter(_sourceNames);
+        }
+    }
+
+}

src/Discord.Net.WebSocket/Audio/AudioClient.cs

@@ -1,14 +1,15 @@
 using Discord.API.Voice;
 using Discord.Audio.Streams;
 using Discord.Logging;
-using Discord.Net;
 using Discord.Net.Converters;
 using Discord.WebSocket;
+using Discord.WebSocket.Diagnostics;
 using Newtonsoft.Json;
 using Newtonsoft.Json.Linq;
 using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.Linq;
 using System.Net.WebSockets;
 using System.Text;
@@ -58,6 +59,7 @@ public StreamPair(AudioInStream reader, AudioOutStream writer)
         private StopReason _stopReason;
         private bool _resuming;
 
+        public int ClientId { get; }
         public SocketGuild Guild { get; }
         public DiscordVoiceAPIClient ApiClient { get; private set; }
         public int Latency { get; private set; }
@@ -73,21 +75,37 @@ public StreamPair(AudioInStream reader, AudioOutStream writer)
         internal AudioClient(SocketGuild guild, int clientId, ulong channelId)
         {
             Guild = guild;
+            ClientId = clientId;
             ChannelId = channelId;
             _audioLogger = Discord.LogManager.CreateLogger($"Audio #{clientId}");
 
             ApiClient = new DiscordVoiceAPIClient(guild.Id, Discord.WebSocketProvider, Discord.UdpSocketProvider);
-            ApiClient.SentGatewayMessage += async opCode => await _audioLogger.DebugAsync($"Sent {opCode}").ConfigureAwait(false);
+            ApiClient.SentGatewayMessage += async opCode =>
+            {
+                AudioMeter.RecordSocketEventSent(opCode, this);
+                await _audioLogger.DebugAsync($"Sent {opCode}").ConfigureAwait(false);
+            };
             ApiClient.SentDiscovery += async () => await _audioLogger.DebugAsync("Sent Discovery").ConfigureAwait(false);
-            //ApiClient.SentData += async bytes => await _audioLogger.DebugAsync($"Sent {bytes} Bytes").ConfigureAwait(false);
+            ApiClient.SentData += bytes =>
+            {
+                //await _audioLogger.DebugAsync($"Sent {bytes} Bytes").ConfigureAwait(false);
+                AudioMeter.RecordBytesSent(bytes, this);
+                return Task.CompletedTask;
+            };
+
             ApiClient.ReceivedEvent += ProcessMessageAsync;
             ApiClient.ReceivedPacket += ProcessPacketAsync;
 
             _stateLock = new SemaphoreSlim(1, 1);
             _connection = new ConnectionManager(_stateLock, _audioLogger, ConnectionTimeoutMs,
                 OnConnectingAsync, OnDisconnectingAsync, x => ApiClient.Disconnected += x);
             _connection.Connected += () => _connectedEvent.InvokeAsync();
-            _connection.Disconnected += (exception, _) => _disconnectedEvent.InvokeAsync(exception);
+            _connection.Disconnected += (exception, reconnect) =>
+            {
+                if (reconnect)
+                    AudioMeter.AddAudioReconnect(this);
+                return _disconnectedEvent.InvokeAsync(exception);
+            };
             _heartbeatTimes = new ConcurrentQueue<long>();
             _keepaliveTimes = new ConcurrentQueue<KeyValuePair<ulong, int>>();
             _ssrcMap = new ConcurrentDictionary<uint, ulong>();
@@ -100,8 +118,16 @@ internal AudioClient(SocketGuild guild, int clientId, ulong channelId)
                 e.ErrorContext.Handled = true;
             };
 
-            LatencyUpdated += async (old, val) => await _audioLogger.DebugAsync($"Latency = {val} ms").ConfigureAwait(false);
-            UdpLatencyUpdated += async (old, val) => await _audioLogger.DebugAsync($"UDP Latency = {val} ms").ConfigureAwait(false);
+            LatencyUpdated += async (old, val) =>
+            {
+                AudioMeter.RecordSocketLatency((double)val / 1000, this);
+                await _audioLogger.DebugAsync($"Latency = {val} ms").ConfigureAwait(false);
+            };
+            UdpLatencyUpdated += async (old, val) =>
+            {
+                await _audioLogger.DebugAsync($"UDP Latency = {val} ms").ConfigureAwait(false);
+                AudioMeter.RecordUdpLatency((double)val / 1000, this);
+            };
         }
 
         internal Task StartAsync(string url, ulong userId, string sessionId, string token)
@@ -132,6 +158,7 @@ private async Task OnConnectingAsync()
             await _audioLogger.DebugAsync($"Connecting ApiClient. Voice server: wss://{_url}").ConfigureAwait(false);
             await ApiClient.ConnectAsync($"wss://{_url}?v={DiscordConfig.VoiceAPIVersion}").ConfigureAwait(false);
             await _audioLogger.DebugAsync($"Listening on port {ApiClient.UdpPort}").ConfigureAwait(false);
+            AudioMeter.AddAudioConnections(1, this);
 
             if (!_resuming)
             {
@@ -151,6 +178,7 @@ private async Task OnDisconnectingAsync(Exception ex)
         {
             await _audioLogger.DebugAsync("Disconnecting ApiClient").ConfigureAwait(false);
             await ApiClient.DisconnectAsync().ConfigureAwait(false);
+            AudioMeter.AddAudioConnections(-1, this);
 
             if (_stopReason == StopReason.Unknown && ex.InnerException is WebSocketException exception)
             {
@@ -303,6 +331,9 @@ private async Task ProcessMessageAsync(VoiceOpCode opCode, object payload)
         {
             _lastMessageTime = Environment.TickCount;
 
+            var activity = AudioActivity.StartEventReceivedActivity(opCode, this);
+            var watch = Stopwatch.StartNew();
+
             try
             {
                 switch (opCode)
@@ -388,7 +419,7 @@ private async Task ProcessMessageAsync(VoiceOpCode opCode, object payload)
                             _heartbeatTask = RunHeartbeatAsync(_heartbeatInterval, _connection.CancelToken);
                             _keepaliveTask = RunKeepaliveAsync(_connection.CancelToken);
 
-                            _ = _connection.CompleteAsync();
+                        _ = _connection.CompleteAsync();
                         }
                         break;
                     default:
@@ -398,11 +429,22 @@ private async Task ProcessMessageAsync(VoiceOpCode opCode, object payload)
             }
             catch (Exception ex)
             {
+                activity?.AddExceptionToActivity(ex);
+                AudioMeter.RecordSocketEventException(ex, opCode, this);
+
                 await _audioLogger.ErrorAsync($"Error handling {opCode}", ex).ConfigureAwait(false);
             }
+            finally
+            {
+                watch.Stop();
+                AudioMeter.RecordSocketEventReceived(watch.Elapsed, opCode, this);
+
+                activity?.Dispose();
+            }
         }
         private async Task ProcessPacketAsync(byte[] packet)
         {
+            AudioMeter.RecordBytesReceived(packet.Length, this);
             try
             {
                 if (_connection.State == ConnectionState.Connecting)

src/Discord.Net.WebSocket/Diagnostics/AudioActivity.cs

@@ -0,0 +1,32 @@
+using Discord.Audio;
+using Discord.API.Voice;
+using System;
+
+#if NET5_0_OR_GREATER
+using System.Collections.Generic;
+using System.Diagnostics;
+#endif
+
+namespace Discord.WebSocket.Diagnostics
+{
+    public static class AudioActivity
+    {
+#if NET5_0_OR_GREATER
+        private static readonly ActivitySource _source = new("Discord.Net.Audio", typeof(DiagnosticTags).Assembly.GetName().Version!.ToString());
+
+        internal static Activity StartEventReceivedActivity(VoiceOpCode opCode, AudioClient client)
+        {
+            Activity.Current = null;     // This activity doesn't have a parent so it have to be explicitly set
+
+            IEnumerable<KeyValuePair<string, object>> tags = [
+                .. DiagnosticTags.CreateAudioClientTags(client),
+                .. DiagnosticTags.CreateAudioEventTags(opCode)
+            ];
+            return _source.StartActivity($"process {opCode}", ActivityKind.Consumer, null, tags: tags);
+        }
+
+#else
+        internal static IDisposable StartEventReceivedActivity(VoiceOpCode opCode, AudioClient client) => null;
+#endif
+    }
+}