[Exporter.Geneva] Add TraceState support

src/OpenTelemetry.Exporter.Geneva/.publicApi/PublicAPI.Unshipped.txt

@@ -0,0 +1,2 @@
+OpenTelemetry.Exporter.Geneva.GenevaExporterOptions.IncludeTraceStateForSpan.get -> bool
+OpenTelemetry.Exporter.Geneva.GenevaExporterOptions.IncludeTraceStateForSpan.set -> void

src/OpenTelemetry.Exporter.Geneva/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+* Update GenevaTraceExporter to export `activity.TraceStateString` as the value
+  for Part B `traceState` field when the `IncludeTraceState` option is set to `true`.
+  ([#1850](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/1850))
+
 ## 1.9.0-alpha.1
 
 Released 2024-May-22

src/OpenTelemetry.Exporter.Geneva/GenevaExporterOptions.cs

@@ -25,6 +25,8 @@ public class GenevaExporterOptions
 
     public EventNameExportMode EventNameExportMode { get; set; }
 
+    public bool IncludeTraceStateForSpan { get; set; }
+
     public IReadOnlyDictionary<string, string> TableNameMappings
     {
         get => this._tableNameMappings;

src/OpenTelemetry.Exporter.Geneva/MsgPackExporter/MsgPackTraceExporter.cs

@@ -91,6 +91,8 @@ public MsgPackTraceExporter(GenevaExporterOptions options)
 #endif
         }
 
+        this.m_shouldIncludeTraceState = options.IncludeTraceStateForSpan;
+
         var buffer = new byte[BUFFER_SIZE];
 
         var cursor = 0;
@@ -243,6 +245,17 @@ internal int SerializeActivity(Activity activity)
             cntFields += 1;
         }
 
+        if (this.m_shouldIncludeTraceState)
+        {
+            var traceStateString = activity.TraceStateString;
+            if (!string.IsNullOrEmpty(traceStateString))
+            {
+                cursor = MessagePackSerializer.SerializeAsciiString(buffer, cursor, "traceState");
+                cursor = MessagePackSerializer.SerializeUnicodeString(buffer, cursor, traceStateString);
+                cntFields += 1;
+            }
+        }
+
         var linkEnumerator = activity.EnumerateLinks();
         if (linkEnumerator.MoveNext())
         {
@@ -453,5 +466,7 @@ public void Dispose()
     private readonly HashSet<string> m_dedicatedFields;
 #endif
 
+    private readonly bool m_shouldIncludeTraceState;
+
     private bool isDisposed;
 }

src/OpenTelemetry.Exporter.Geneva/TLDExporter/TldTraceExporter.cs

@@ -43,6 +43,7 @@ internal sealed class TldTraceExporter : TldExporter, IDisposable
     private readonly byte partAFieldsCount = 3; // At least three fields: time, ext_dt_traceId, ext_dt_spanId
     private readonly HashSet<string> m_customFields;
     private readonly Tuple<byte[], byte[]> repeatedPartAFields;
+    private readonly bool m_shouldIncludeTraceState;
 
     private readonly EventProvider eventProvider;
 
@@ -114,6 +115,8 @@ public TldTraceExporter(GenevaExporterOptions options)
                 this.repeatedPartAFields = eb.GetRawFields();
             }
         }
+
+        this.m_shouldIncludeTraceState = options.IncludeTraceStateForSpan;
     }
 
     public ExportResult Export(in Batch<Activity> batch)
@@ -205,6 +208,16 @@ internal void SerializeActivity(Activity activity)
             partBFieldsCount++;
         }
 
+        if (this.m_shouldIncludeTraceState)
+        {
+            var traceStateString = activity.TraceStateString;
+            if (!string.IsNullOrEmpty(traceStateString))
+            {
+                eb.AddCountedAnsiString("traceState", traceStateString, Encoding.UTF8);
+                partBFieldsCount++;
+            }
+        }
+
         var linkEnumerator = activity.EnumerateLinks();
         if (linkEnumerator.MoveNext())
         {

test/OpenTelemetry.Exporter.Geneva.Tests/GenevaTraceExporterTests.cs

@@ -195,11 +195,15 @@ public void GenevaTraceExporter_Success_Windows()
     }
 
     [Theory]
-    [InlineData(false, false)]
-    [InlineData(false, true)]
-    [InlineData(true, false)]
-    [InlineData(true, true)]
-    public void GenevaTraceExporter_Serialization_Success(bool hasTableNameMapping, bool hasCustomFields)
+    [InlineData(false, false, false)]
+    [InlineData(false, true, false)]
+    [InlineData(true, false, false)]
+    [InlineData(true, true, false)]
+    [InlineData(false, false, true)]
+    [InlineData(false, true, true)]
+    [InlineData(true, false, true)]
+    [InlineData(true, true, true)]
+    public void GenevaTraceExporter_Serialization_Success(bool hasTableNameMapping, bool hasCustomFields, bool includeTraceState)
     {
         string path = string.Empty;
         Socket server = null;
@@ -241,6 +245,11 @@ public void GenevaTraceExporter_Serialization_Success(bool hasTableNameMapping,
                 exporterOptions.CustomFields = new string[] { "clientRequestId" };
             }
 
+            if (includeTraceState)
+            {
+                exporterOptions.IncludeTraceStateForSpan = true;
+            }
+
             using var exporter = new MsgPackTraceExporter(exporterOptions);
 #if NET8_0_OR_GREATER
             var dedicatedFields = typeof(MsgPackTraceExporter).GetField("m_dedicatedFields", BindingFlags.NonPublic | BindingFlags.Instance).GetValue(exporter) as FrozenSet<string>;
@@ -278,6 +287,11 @@ public void GenevaTraceExporter_Serialization_Success(bool hasTableNameMapping,
                 var linkedtraceId2 = ActivityTraceId.CreateFromString("e8ea7e9ac72de94e91fabc613f9686a2".AsSpan());
                 var linkedSpanId2 = ActivitySpanId.CreateFromString("888915b6286b9c02".AsSpan());
 
+                if (includeTraceState)
+                {
+                    parentActivity.TraceStateString = "some=state";
+                }
+
                 var links = new[]
                 {
                     new ActivityLink(new ActivityContext(
@@ -659,6 +673,15 @@ private void AssertFluentdForwardModeForActivity(GenevaExporterOptions exporterO
             Assert.Equal(activity.ParentSpanId.ToHexString(), mapping["parentId"]);
         }
 
+        if (!exporterOptions.IncludeTraceStateForSpan || string.IsNullOrEmpty(activity.TraceStateString))
+        {
+            Assert.False(mapping.ContainsKey("traceState"));
+        }
+        else
+        {
+            Assert.Equal(activity.TraceStateString, mapping["traceState"]);
+        }
+
         #region Assert Activity Links
         if (activity.Links.Any())
         {