[Instrumentation.SqlClient] Introducing context propagation to SQL Server

src/OpenTelemetry.Instrumentation.SqlClient/.publicApi/PublicAPI.Unshipped.txt

@@ -9,6 +9,8 @@ OpenTelemetry.Instrumentation.SqlClient.SqlClientTraceInstrumentationOptions.Rec
 OpenTelemetry.Instrumentation.SqlClient.SqlClientTraceInstrumentationOptions.SetDbStatementForText.get -> bool
 OpenTelemetry.Instrumentation.SqlClient.SqlClientTraceInstrumentationOptions.SetDbStatementForText.set -> void
 OpenTelemetry.Instrumentation.SqlClient.SqlClientTraceInstrumentationOptions.SqlClientTraceInstrumentationOptions() -> void
+OpenTelemetry.Instrumentation.SqlClient.SqlClientTraceInstrumentationOptions.ContextPropagationLevel.get -> string!
+OpenTelemetry.Instrumentation.SqlClient.SqlClientTraceInstrumentationOptions.ContextPropagationLevel.set -> void
 OpenTelemetry.Metrics.SqlClientMeterProviderBuilderExtensions
 OpenTelemetry.Trace.TracerProviderBuilderExtensions
 static OpenTelemetry.Metrics.SqlClientMeterProviderBuilderExtensions.AddSqlClientInstrumentation(this OpenTelemetry.Metrics.MeterProviderBuilder! builder) -> OpenTelemetry.Metrics.MeterProviderBuilder!

src/OpenTelemetry.Instrumentation.SqlClient/CHANGELOG.md

@@ -10,6 +10,14 @@
   the new conventions.
   ([#2811](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/2811))
 
+* Added `ContextPropagationLevel` option to propagate trace context to
+  SQL Server database.
+  ([#2709](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/2709))
+
+  Valid options:
+  * `trace`: Propagate traceparent info to SQL Server database (see [SET CONTEXT_INFO](https://learn.microsoft.com/en-us/sql/t-sql/statements/set-context-info-transact-sql?view=sql-server-ver16))
+  * `disabled`: Default value
+
 ## 1.12.0-beta.1
 
 Released 2025-May-06

src/OpenTelemetry.Instrumentation.SqlClient/Implementation/SqlClientDiagnosticListener.cs

@@ -8,6 +8,7 @@
 using System.Diagnostics.CodeAnalysis;
 #endif
 using System.Globalization;
+using System.Text;
 using OpenTelemetry.Trace;
 
 namespace OpenTelemetry.Instrumentation.SqlClient.Implementation;
@@ -26,6 +27,9 @@ internal sealed class SqlClientDiagnosticListener : ListenerHandler
     public const string SqlDataWriteCommandError = "System.Data.SqlClient.WriteCommandError";
     public const string SqlMicrosoftWriteCommandError = "Microsoft.Data.SqlClient.WriteCommandError";
 
+    private const string ContextInfoParameterName = "@opentelemetry_traceparent";
+    private const string SetContextSql = $"set context_info {ContextInfoParameterName}";
+
     private readonly PropertyFetcher<object> commandFetcher = new("Command");
     private readonly PropertyFetcher<object> connectionFetcher = new("Connection");
     private readonly PropertyFetcher<string> dataSourceFetcher = new("DataSource");
@@ -64,6 +68,13 @@ public override void OnEventWritten(string name, object? payload)
                         return;
                     }
 
+                    // skip if this is an injected query
+                    if (options.ContextPropagationLevel == SqlClientTraceInstrumentationOptions.ContextPropagationLevelTrace &&
+                        command is IDbCommand { CommandType: CommandType.Text, CommandText: SetContextSql })
+                    {
+                        return;
+                    }
+
                     _ = this.connectionFetcher.TryFetch(command, out var connection);
                     _ = this.databaseFetcher.TryFetch(connection, out var databaseName);
                     _ = this.dataSourceFetcher.TryFetch(connection, out var dataSource);
@@ -82,6 +93,25 @@ public override void OnEventWritten(string name, object? payload)
                         return;
                     }
 
+                    if (options.ContextPropagationLevel == SqlClientTraceInstrumentationOptions.ContextPropagationLevelTrace &&
+                        command is IDbCommand { CommandType: CommandType.Text, Connection.State: ConnectionState.Open } iDbCommand)
+                    {
+                        var setContextCommand = iDbCommand.Connection.CreateCommand();
+                        setContextCommand.CommandText = SetContextSql;
+                        setContextCommand.CommandType = CommandType.Text;
+                        var parameter = setContextCommand.CreateParameter();
+                        parameter.ParameterName = ContextInfoParameterName;
+
+                        var tracedflags = (activity.ActivityTraceFlags & ActivityTraceFlags.Recorded) != 0 ? "01" : "00";
+                        var traceparent = $"00-{activity.TraceId.ToHexString()}-{activity.SpanId.ToHexString()}-{tracedflags}";
+
+                        parameter.DbType = DbType.Binary;
+                        parameter.Value = Encoding.UTF8.GetBytes(traceparent);
+                        setContextCommand.Parameters.Add(parameter);
+
+                        setContextCommand.ExecuteNonQuery();
+                    }
+
                     if (activity.IsAllDataRequested)
                     {
                         try
@@ -168,6 +198,15 @@ public override void OnEventWritten(string name, object? payload)
             case SqlDataAfterExecuteCommand:
             case SqlMicrosoftAfterExecuteCommand:
                 {
+                    _ = this.commandFetcher.TryFetch(payload, out var command);
+
+                    // skip if this is an injected query
+                    if (options.ContextPropagationLevel == SqlClientTraceInstrumentationOptions.ContextPropagationLevelTrace &&
+                        command is IDbCommand { CommandType: CommandType.Text, CommandText: SetContextSql })
+                    {
+                        return;
+                    }
+
                     if (activity == null)
                     {
                         SqlClientInstrumentationEventSource.Log.NullActivity(name);
@@ -189,6 +228,15 @@ public override void OnEventWritten(string name, object? payload)
             case SqlDataWriteCommandError:
             case SqlMicrosoftWriteCommandError:
                 {
+                    _ = this.commandFetcher.TryFetch(payload, out var command);
+
+                    // skip if this is an injected query
+                    if (options.ContextPropagationLevel == SqlClientTraceInstrumentationOptions.ContextPropagationLevelTrace &&
+                        command is IDbCommand { CommandType: CommandType.Text, CommandText: SetContextSql })
+                    {
+                        return;
+                    }
+
                     if (activity == null)
                     {
                         SqlClientInstrumentationEventSource.Log.NullActivity(name);

src/OpenTelemetry.Instrumentation.SqlClient/SqlClientTraceInstrumentationOptions.cs

@@ -17,6 +17,16 @@ namespace OpenTelemetry.Instrumentation.SqlClient;
 /// </remarks>
 public class SqlClientTraceInstrumentationOptions
 {
+    /// <summary>
+    /// Flag to send traceparent information to SQL Server.
+    /// </summary>
+    internal const string ContextPropagationLevelTrace = "trace";
+
+    /// <summary>
+    /// Flag to disable sending trace information to SQL Server.
+    /// </summary>
+    internal const string ContextPropagationDisabled = "disabled";
+
     /// <summary>
     /// Initializes a new instance of the <see cref="SqlClientTraceInstrumentationOptions"/> class.
     /// </summary>
@@ -30,6 +40,7 @@ internal SqlClientTraceInstrumentationOptions(IConfiguration configuration)
         var databaseSemanticConvention = GetSemanticConventionOptIn(configuration);
         this.EmitOldAttributes = databaseSemanticConvention.HasFlag(DatabaseSemanticConvention.Old);
         this.EmitNewAttributes = databaseSemanticConvention.HasFlag(DatabaseSemanticConvention.New);
+        this.ContextPropagationLevel = ContextPropagationDisabled;
     }
 
     /// <summary>
@@ -63,6 +74,17 @@ internal SqlClientTraceInstrumentationOptions(IConfiguration configuration)
     /// </remarks>
     public bool SetDbStatementForText { get; set; }
 
+    /// <summary>
+    /// Gets or sets a value indicating whether to send trace information to SQL Server database.
+    /// Optional values:
+    /// <see langword="trace"/>:
+    /// Send traceparent information to SQL Server.
+    /// <see langword="disabled"/>:
+    /// Disable sending trace information to SQL Server.
+    /// Default value: <see landword="disabled"/>.
+    /// </summary>
+    public string ContextPropagationLevel { get; set; }
+
     /// <summary>
     /// Gets or sets an action to enrich an <see cref="Activity"/> with the
     /// raw <c>SqlCommand</c> object.

test/OpenTelemetry.Instrumentation.SqlClient.Tests/SqlClientIntegrationTests.cs

@@ -56,6 +56,7 @@ public void SuccessfulCommandTest(
             {
                 options.SetDbStatementForText = captureTextCommandContent;
                 options.RecordException = recordException;
+                options.ContextPropagationLevel = SqlClientTraceInstrumentationOptions.ContextPropagationLevelTrace;
             })
             .Build();