From 028904fa836653e202390329f0947637b9c23488 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Thomas=20J=C3=A4ckle?= <thomas.jaeckle@beyonnex.io>
Date: Wed, 29 Jan 2025 16:01:18 +0100
Subject: [PATCH] fix tracestate propagation

---
 .../utils/tracing/span/StartedKamonSpan.java       | 14 +++++++++++---
 .../model/ImmutableThingFromScratchBuilder.java    |  4 ++--
 .../eclipse/ditto/things/model/ThingBuilder.java   |  2 +-
 3 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/internal/utils/tracing/src/main/java/org/eclipse/ditto/internal/utils/tracing/span/StartedKamonSpan.java b/internal/utils/tracing/src/main/java/org/eclipse/ditto/internal/utils/tracing/span/StartedKamonSpan.java
index 09d71cac2d..051b091bcc 100644
--- a/internal/utils/tracing/src/main/java/org/eclipse/ditto/internal/utils/tracing/span/StartedKamonSpan.java
+++ b/internal/utils/tracing/src/main/java/org/eclipse/ditto/internal/utils/tracing/span/StartedKamonSpan.java
@@ -18,8 +18,10 @@
 import java.time.Instant;
 import java.util.Map;
 
+import javax.annotation.Nullable;
 import javax.annotation.concurrent.ThreadSafe;
 
+import org.eclipse.ditto.base.model.headers.DittoHeaderDefinition;
 import org.eclipse.ditto.internal.utils.metrics.instruments.tag.Tag;
 import org.eclipse.ditto.internal.utils.metrics.instruments.tag.TagSet;
 
@@ -113,11 +115,17 @@ public SpanOperationName getOperationName() {
 
     @Override
     public Map<String, String> propagateContext(final Map<String, String> headers) {
-        return httpContextPropagation.propagateContextToHeaders(wrapSpanInContext(), headers);
+        return httpContextPropagation.propagateContextToHeaders(wrapSpanInContext(
+                headers.get(DittoHeaderDefinition.W3C_TRACESTATE.getKey())
+        ), headers);
     }
 
-    private Context wrapSpanInContext() {
-        return Context.of(Span.Key(), span);
+    private Context wrapSpanInContext(@Nullable final String traceStateHeader) {
+        if (traceStateHeader != null) {
+            return Context.of(Span.Key(), span, Context.key("tracestate", ""), traceStateHeader);
+        } else {
+            return Context.of(Span.Key(), span);
+        }
     }
 
     @Override
diff --git a/things/model/src/main/java/org/eclipse/ditto/things/model/ImmutableThingFromScratchBuilder.java b/things/model/src/main/java/org/eclipse/ditto/things/model/ImmutableThingFromScratchBuilder.java
index 23d8ebdeb0..a967a74b11 100755
--- a/things/model/src/main/java/org/eclipse/ditto/things/model/ImmutableThingFromScratchBuilder.java
+++ b/things/model/src/main/java/org/eclipse/ditto/things/model/ImmutableThingFromScratchBuilder.java
@@ -20,10 +20,10 @@
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.NotThreadSafe;
 
+import org.eclipse.ditto.base.model.entity.metadata.Metadata;
 import org.eclipse.ditto.json.JsonObject;
 import org.eclipse.ditto.json.JsonPointer;
 import org.eclipse.ditto.json.JsonValue;
-import org.eclipse.ditto.base.model.entity.metadata.Metadata;
 import org.eclipse.ditto.policies.model.PolicyId;
 
 /**
@@ -169,7 +169,7 @@ public FromScratch setFeature(final String featureId) {
 
     @Override
     public FromScratch setFeature(final String featureId, @Nullable final FeatureDefinition featureDefinition,
-            final FeatureProperties featureProperties) {
+            @Nullable final FeatureProperties featureProperties) {
 
         return setFeature(ThingsModelFactory.newFeature(featureId, featureDefinition, featureProperties));
     }
diff --git a/things/model/src/main/java/org/eclipse/ditto/things/model/ThingBuilder.java b/things/model/src/main/java/org/eclipse/ditto/things/model/ThingBuilder.java
index 8d29c9337a..5bb1e0f679 100755
--- a/things/model/src/main/java/org/eclipse/ditto/things/model/ThingBuilder.java
+++ b/things/model/src/main/java/org/eclipse/ditto/things/model/ThingBuilder.java
@@ -196,7 +196,7 @@ interface FromScratch {
          * @throws NullPointerException if {@code featureId} is {@code null}.
          */
         FromScratch setFeature(String featureId, FeatureDefinition featureDefinition,
-                FeatureProperties featureProperties);
+                @Nullable FeatureProperties featureProperties);
 
         /**
          * Sets a Feature with the given ID and properties to this builder. A previously set Feature with the