Refactor span tag processing API

dd-trace-core/src/main/java/datadog/trace/civisibility/writer/ddintake/CiTestCycleMapperV1.java

@@ -5,6 +5,7 @@
 import static datadog.json.JsonMapper.toJson;
 import static datadog.trace.api.cache.RadixTreeCache.UNSET_STATUS;
 import static datadog.trace.api.civisibility.CIConstants.MAX_META_STRING_VALUE_LENGTH;
+import static datadog.trace.core.CoreSpan.OWN_PROPAGATION_TAGS;
 import static datadog.trace.util.Strings.truncate;
 
 import datadog.communication.serialization.GrowableBuffer;
@@ -222,7 +223,7 @@ public void map(List<? extends CoreSpan<?>> trace, Writable writable) {
       writable.writeUTF8(ERROR);
       writable.writeInt(span.getError());
       /* 7 (meta), 8 (metrics) */
-      span.processTagsAndBaggage(metaWriter.withWritable(writable));
+      span.processTagsAndBaggage(metaWriter.withWritable(writable), OWN_PROPAGATION_TAGS);
     }
     eventCount += trace.size();
     serializationTimeMillis += (int) (System.currentTimeMillis() - serializationStartTimestamp);

dd-trace-core/src/main/java/datadog/trace/common/writer/FileBasedPayloadDispatcher.java

@@ -3,6 +3,7 @@
 import static datadog.json.JsonMapper.toJson;
 import static datadog.trace.api.cache.RadixTreeCache.UNSET_STATUS;
 import static datadog.trace.api.civisibility.CIConstants.MAX_META_STRING_VALUE_LENGTH;
+import static datadog.trace.core.CoreSpan.OWN_PROPAGATION_TAGS;
 import static datadog.trace.util.Strings.truncate;
 
 import datadog.json.JsonWriter;
@@ -270,7 +271,7 @@ private String serializeTestEvent(CoreSpan<?> span) {
     w.name("duration").value(span.getDurationNano());
     w.name("error").value(span.getError());
 
-    span.processTagsAndBaggage(new JsonMetaWriter(w));
+    span.processTagsAndBaggage(new JsonMetaWriter(w), OWN_PROPAGATION_TAGS);
 
     w.endObject(); // content
     w.endObject(); // event

dd-trace-core/src/main/java/datadog/trace/common/writer/ListWriter.java

@@ -1,5 +1,6 @@
 package datadog.trace.common.writer;
 
+import static datadog.trace.core.CoreSpan.OWN_PROPAGATION_TAGS;
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
 import static java.util.concurrent.TimeUnit.NANOSECONDS;
 import static java.util.concurrent.TimeUnit.SECONDS;
@@ -46,7 +47,7 @@ public void write(List<DDSpan> trace) {
     for (DDSpan span : trace) {
       // This is needed to properly do all delayed processing to make this writer even
       // remotely realistic so the test actually test something
-      span.processTagsAndBaggage(metadataConsumer);
+      span.processTagsAndBaggage(metadataConsumer, OWN_PROPAGATION_TAGS);
     }
 
     add(trace);

dd-trace-core/src/main/java/datadog/trace/common/writer/ddagent/TraceMapperV0_4.java

@@ -2,6 +2,7 @@
 
 import static datadog.communication.http.OkHttpUtils.msgpackRequestBodyOf;
 import static datadog.trace.api.cache.RadixTreeCache.UNSET_STATUS;
+import static datadog.trace.core.CoreSpan.ROOT_PROPAGATION_TAGS;
 
 import datadog.communication.serialization.Codec;
 import datadog.communication.serialization.GenerationalUtf8Cache;
@@ -367,7 +368,7 @@ public void map(List<? extends CoreSpan<?>> trace, final Writable writable) {
           metaWriter
               .withWritable(writable)
               .forSpan(i == 0, i == trace.size() - 1, !firstSpanWritten),
-          i == 0);
+          i == 0 ? ROOT_PROPAGATION_TAGS : 0);
       if (!metaStruct.isEmpty()) {
         /* 13 */
         metaStructWriter.withWritable(writable).write(metaStruct);

dd-trace-core/src/main/java/datadog/trace/common/writer/ddagent/TraceMapperV0_5.java

@@ -2,6 +2,7 @@
 
 import static datadog.communication.http.OkHttpUtils.msgpackRequestBodyOf;
 import static datadog.trace.api.cache.RadixTreeCache.UNSET_STATUS;
+import static datadog.trace.core.CoreSpan.ROOT_PROPAGATION_TAGS;
 
 import datadog.communication.serialization.GrowableBuffer;
 import datadog.communication.serialization.Mapper;
@@ -85,7 +86,7 @@ public void map(final List<? extends CoreSpan<?>> trace, final Writable writable
           metaWriter
               .withWritable(writable)
               .forSpan(i == 0, i == trace.size() - 1, !firstSpanWritten),
-          i == 0);
+          i == 0 ? ROOT_PROPAGATION_TAGS : 0);
       /* 12 */
       writeDictionaryEncoded(writable, span.getType());
       firstSpanWritten = true;

dd-trace-core/src/main/java/datadog/trace/common/writer/ddagent/TraceMapperV1.java

@@ -3,6 +3,9 @@
 import static datadog.communication.http.OkHttpUtils.msgpackRequestBodyOf;
 import static datadog.trace.api.DDTags.SPAN_EVENTS;
 import static datadog.trace.api.cache.RadixTreeCache.UNSET_STATUS;
+import static datadog.trace.core.CoreSpan.ROOT_PROPAGATION_TAGS;
+import static datadog.trace.core.CoreSpan.STRUCTURED_EVENTS;
+import static datadog.trace.core.CoreSpan.STRUCTURED_LINKS;
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.singletonMap;
 
@@ -44,6 +47,9 @@
 public final class TraceMapperV1 implements TraceMapper {
   private static final Logger log = LoggerFactory.getLogger(TraceMapperV1.class);
 
+  /** Span links and events are encoded natively rather than as tags. */
+  private static final int STRUCTURED_LINKS_AND_EVENTS = STRUCTURED_LINKS | STRUCTURED_EVENTS;
+
   // Attribute value types (from V1 spec)
   static final int VALUE_TYPE_STRING = 1;
   static final int VALUE_TYPE_BOOLEAN = 2;
@@ -92,7 +98,8 @@ public void map(List<? extends CoreSpan<?>> trace, Writable writable) {
     }
 
     CoreSpan<?> firstSpan = trace.get(0);
-    firstSpan.processTagsAndBaggageWithStructuredLinksAndEvents(spanMetadata, true);
+    firstSpan.processTagsAndBaggage(
+        spanMetadata, STRUCTURED_LINKS_AND_EVENTS | ROOT_PROPAGATION_TAGS);
     Metadata firstSpanMeta = spanMetadata.metadata;
 
     // encoded fields: 1..7, but skipping #5, as not required by tracers and set by the agent.
@@ -132,7 +139,8 @@ private void encodeSpans(Writable writable, int fieldId, List<? extends CoreSpan
     for (int i = 0; i < spans.size(); i++) {
       CoreSpan<?> span = spans.get(i);
       if (meta == null) {
-        span.processTagsAndBaggageWithStructuredLinksAndEvents(spanMetadata, i == 0);
+        span.processTagsAndBaggage(
+            spanMetadata, STRUCTURED_LINKS_AND_EVENTS | (i == 0 ? ROOT_PROPAGATION_TAGS : 0));
         meta = spanMetadata.metadata;
       }
       TagMap tags = meta.getTags();

dd-trace-core/src/main/java/datadog/trace/core/CoreSpan.java

@@ -92,32 +92,34 @@ default String getSpanKindString() {
   /**
    * Runs early {@link datadog.trace.core.tagprocessor.TagsPostProcessor} like base service and peer
    * service computation. Such tags are needed before span serialization so they can’t be processed
-   * lazily as part of the {@link #processTagsAndBaggage(MetadataConsumer)} API.
+   * lazily as part of the {@link #processTagsAndBaggage(MetadataConsumer, int)} API.
    */
   void processServiceTags();
 
-  void processTagsAndBaggage(MetadataConsumer consumer);
+  /** The serialization protocol encodes span links natively, so they are not added as a tag. */
+  int STRUCTURED_LINKS = 1;
 
-  default void processTagsAndBaggage(MetadataConsumer consumer, boolean firstInChunk) {
-    processTagsAndBaggage(consumer);
-  }
+  /** The serialization protocol encodes span events natively, so they are not added as a tag. */
+  int STRUCTURED_EVENTS = 1 << 1;
 
   /**
-   * Variant of {@link #processTagsAndBaggage(MetadataConsumer)} for protocols that serialize span
-   * links and span events as first-class structured data rather than tags. Baggage tag injection
-   * still follows the tracer configuration.
-   *
-   * <p>To simplify tests, by default delegating to {@link
-   * #processTagsAndBaggage(MetadataConsumer)}.
+   * Serializes the span context own propagation tags. This is the default option, for tag-based
+   * protocols that serialize each span independently.
    */
-  default void processTagsAndBaggageWithStructuredLinksAndEvents(MetadataConsumer consumer) {
-    processTagsAndBaggage(consumer);
-  }
+  int OWN_PROPAGATION_TAGS = 1 << 2;
 
-  default void processTagsAndBaggageWithStructuredLinksAndEvents(
-      MetadataConsumer consumer, boolean firstInChunk) {
-    processTagsAndBaggageWithStructuredLinksAndEvents(consumer);
-  }
+  /** Serializes the local root span context propagation tags, as for the first span of a chunk. */
+  int ROOT_PROPAGATION_TAGS = 1 << 3;
+
+  /**
+   * Processes the span tags and baggage, and hands the resulting {@link Metadata} to the consumer.
+   *
+   * @param consumer The consumer of the span metadata.
+   * @param options A combination of {@link #STRUCTURED_LINKS}, {@link #STRUCTURED_EVENTS}, and
+   *     either {@link #OWN_PROPAGATION_TAGS} (the default option) or {@link
+   *     #ROOT_PROPAGATION_TAGS}.
+   */
+  void processTagsAndBaggage(MetadataConsumer consumer, int options);
 
   T setSamplingPriority(int samplingPriority, int samplingMechanism);
 

dd-trace-core/src/main/java/datadog/trace/core/DDSpan.java

@@ -806,25 +806,8 @@ public void processServiceTags() {
   }
 
   @Override
-  public void processTagsAndBaggage(final MetadataConsumer consumer) {
-    context.processTagsAndBaggage(consumer, longRunningVersion, this);
-  }
-
-  @Override
-  public void processTagsAndBaggage(final MetadataConsumer consumer, final boolean firstInChunk) {
-    context.processTagsAndBaggage(consumer, longRunningVersion, this, firstInChunk);
-  }
-
-  @Override
-  public void processTagsAndBaggageWithStructuredLinksAndEvents(final MetadataConsumer consumer) {
-    context.processTagsAndBaggageWithStructuredLinksAndEvents(consumer, longRunningVersion, this);
-  }
-
-  @Override
-  public void processTagsAndBaggageWithStructuredLinksAndEvents(
-      final MetadataConsumer consumer, final boolean firstInChunk) {
-    context.processTagsAndBaggageWithStructuredLinksAndEvents(
-        consumer, longRunningVersion, this, firstInChunk);
+  public void processTagsAndBaggage(final MetadataConsumer consumer, final int options) {
+    context.processTagsAndBaggage(consumer, longRunningVersion, this, options);
   }
 
   @Override

dd-trace-core/src/main/java/datadog/trace/core/DDSpanContext.java

@@ -5,6 +5,10 @@
 import static datadog.trace.api.DDTags.SPAN_LINKS;
 import static datadog.trace.bootstrap.instrumentation.api.ErrorPriorities.UNSET;
 import static datadog.trace.bootstrap.instrumentation.api.ServiceNameSources.MANUAL;
+import static datadog.trace.core.CoreSpan.OWN_PROPAGATION_TAGS;
+import static datadog.trace.core.CoreSpan.ROOT_PROPAGATION_TAGS;
+import static datadog.trace.core.CoreSpan.STRUCTURED_EVENTS;
+import static datadog.trace.core.CoreSpan.STRUCTURED_LINKS;
 
 import datadog.trace.api.Config;
 import datadog.trace.api.DDSpanId;
@@ -1324,72 +1328,26 @@ void earlyProcessTags(AppendableSpanLinks links) {
     }
   }
 
-  void processTagsAndBaggage(
-      final MetadataConsumer consumer, int longRunningVersion, DDSpan restrictedSpan) {
-    processTagsAndBaggage(
-        consumer,
-        longRunningVersion,
-        restrictedSpan,
-        injectLinksAsTags,
-        true, // injectEventsAsTags
-        injectBaggageAsTags,
-        propagationTags);
-  }
-
-  void processTagsAndBaggage(
-      final MetadataConsumer consumer,
-      int longRunningVersion,
-      DDSpan restrictedSpan,
-      boolean firstInChunk) {
-    processTagsAndBaggage(
-        consumer,
-        longRunningVersion,
-        restrictedSpan,
-        injectLinksAsTags,
-        true, // injectEventsAsTags
-        injectBaggageAsTags,
-        firstInChunk ? getPropagationTags() : null);
-  }
-
   /**
-   * Serialize span links and span events as first-class structured data rather than tags. While
-   * baggage tag injection keeps following the tracer configuration.
+   * Processes the span tags and baggage, and hands the resulting {@link Metadata} to the consumer.
+   *
+   * @param consumer The consumer of the span metadata.
+   * @param longRunningVersion The long-running version of the span.
+   * @param restrictedSpan The span to read links and events from.
+   * @param options The {@link CoreSpan} options describing what the serialization protocol needs.
    */
-  void processTagsAndBaggageWithStructuredLinksAndEvents(
-      final MetadataConsumer consumer, int longRunningVersion, DDSpan restrictedSpan) {
-    processTagsAndBaggage(
-        consumer,
-        longRunningVersion,
-        restrictedSpan,
-        false, // injectLinksAsTags
-        false, // injectEventsAsTags
-        injectBaggageAsTags,
-        propagationTags);
-  }
-
-  void processTagsAndBaggageWithStructuredLinksAndEvents(
-      final MetadataConsumer consumer,
-      int longRunningVersion,
-      DDSpan restrictedSpan,
-      boolean firstInChunk) {
-    processTagsAndBaggage(
-        consumer,
-        longRunningVersion,
-        restrictedSpan,
-        false, // injectLinksAsTags
-        false, // injectEventsAsTags
-        injectBaggageAsTags,
-        firstInChunk ? getPropagationTags() : null);
-  }
-
   void processTagsAndBaggage(
-      final MetadataConsumer consumer,
-      int longRunningVersion,
-      DDSpan restrictedSpan,
-      boolean injectLinksAsTags,
-      boolean injectEventsAsTags,
-      boolean injectBaggageAsTags,
-      PropagationTags serializedPropagationTags) {
+      final MetadataConsumer consumer, int longRunningVersion, DDSpan restrictedSpan, int options) {
+    boolean injectLinksAsTags = this.injectLinksAsTags && (options & STRUCTURED_LINKS) == 0;
+    boolean injectEventsAsTags = (options & STRUCTURED_EVENTS) == 0;
+    PropagationTags serializedPropagationTags;
+    if ((options & ROOT_PROPAGATION_TAGS) != 0) {
+      serializedPropagationTags = getPropagationTags();
+    } else if ((options & OWN_PROPAGATION_TAGS) != 0) {
+      serializedPropagationTags = this.propagationTags;
+    } else {
+      serializedPropagationTags = null;
+    }
     // NOTE: The span is passed for the sole purpose of allowing updating & reading of the span
     // links and events
     // This is a compromise to avoid...
@@ -1418,7 +1376,7 @@ void processTagsAndBaggage(
 
       // Baggage
       Map<String, String> baggageItemsWithPropagationTags;
-      if (injectBaggageAsTags) {
+      if (this.injectBaggageAsTags) {
         baggageItemsWithPropagationTags = new HashMap<>(baggageItems);
         if (w3cBaggage != null) {
           injectW3CBaggageTags(baggageItemsWithPropagationTags);

dd-trace-core/src/main/java/datadog/trace/core/otlp/trace/OtlpTraceJson.java

@@ -14,6 +14,7 @@
 import static datadog.trace.common.writer.ddagent.TraceMapper.SAMPLING_PRIORITY_KEY;
 import static datadog.trace.common.writer.ddagent.TraceMapper.THREAD_ID;
 import static datadog.trace.common.writer.ddagent.TraceMapper.THREAD_NAME;
+import static datadog.trace.core.CoreSpan.OWN_PROPAGATION_TAGS;
 import static datadog.trace.core.otlp.common.OtlpCommonJson.hexSpanId;
 import static datadog.trace.core.otlp.common.OtlpCommonJson.hexTraceId;
 import static datadog.trace.core.otlp.common.OtlpCommonJson.writeAttribute;
@@ -112,7 +113,7 @@ public static void writeSpan(
     if (span.getSpanType() != null) {
       writeSpanTag(writer, SPAN_TYPE, span.getSpanType());
     }
-    span.processTagsAndBaggage(metaWriter);
+    span.processTagsAndBaggage(metaWriter, OWN_PROPAGATION_TAGS);
     writer.endArray();
 
     if (!links.isEmpty()) {

dd-trace-core/src/main/java/datadog/trace/core/otlp/trace/OtlpTraceProto.java

@@ -14,6 +14,7 @@
 import static datadog.trace.common.writer.ddagent.TraceMapper.SAMPLING_PRIORITY_KEY;
 import static datadog.trace.common.writer.ddagent.TraceMapper.THREAD_ID;
 import static datadog.trace.common.writer.ddagent.TraceMapper.THREAD_NAME;
+import static datadog.trace.core.CoreSpan.OWN_PROPAGATION_TAGS;
 import static datadog.trace.core.otlp.common.OtlpCommonProto.I32_WIRE_TYPE;
 import static datadog.trace.core.otlp.common.OtlpCommonProto.I64_WIRE_TYPE;
 import static datadog.trace.core.otlp.common.OtlpCommonProto.LEN_WIRE_TYPE;
@@ -159,7 +160,7 @@ public static int recordSpanMessage(
       writeSpanTag(buf, SPAN_TYPE, span.getSpanType());
     }
 
-    span.processTagsAndBaggage(metaWriter);
+    span.processTagsAndBaggage(metaWriter, OWN_PROPAGATION_TAGS);
 
     if (span.isError()) {
       int stateSize = 2;

dd-trace-core/src/main/java/datadog/trace/llmobs/writer/ddintake/LLMObsSpanMapper.java

@@ -1,6 +1,7 @@
 package datadog.trace.llmobs.writer.ddintake;
 
 import static datadog.communication.http.OkHttpUtils.gzippedMsgpackRequestBodyOf;
+import static datadog.trace.core.CoreSpan.OWN_PROPAGATION_TAGS;
 import static java.util.concurrent.TimeUnit.MINUTES;
 
 import datadog.communication.EvpProxy;
@@ -281,7 +282,8 @@ public void map(List<? extends CoreSpan<?>> trace, Writable writable, boolean re
       }
 
       /* 10 (metrics), 11 (tags), 12 meta — shift down 1 if session_id absent */
-      span.processTagsAndBaggage(metaWriter.withWritable(writable, getErrorsMap(span)));
+      span.processTagsAndBaggage(
+          metaWriter.withWritable(writable, getErrorsMap(span)), OWN_PROPAGATION_TAGS);
     }
 
     // Increase only after all spans have been written. This way, if it rolls back because of a

dd-trace-core/src/test/java/datadog/trace/common/metrics/SimpleSpan.java

@@ -324,7 +324,7 @@ public CharSequence getType() {
   public void processServiceTags() {}
 
   @Override
-  public void processTagsAndBaggage(MetadataConsumer consumer) {}
+  public void processTagsAndBaggage(MetadataConsumer consumer, int options) {}
 
   @Override
   public SimpleSpan setSamplingPriority(int samplingPriority, int samplingMechanism) {

dd-trace-core/src/test/java/datadog/trace/common/writer/FileBasedPayloadDispatcherTest.java

@@ -5,6 +5,7 @@
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyInt;
 import static org.mockito.Mockito.doAnswer;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
@@ -324,7 +325,7 @@ private static CoreSpan<?> mockSpan(CharSequence type, Map<String, Object> tags)
               return null;
             })
         .when(span)
-        .processTagsAndBaggage(any(MetadataConsumer.class));
+        .processTagsAndBaggage(any(MetadataConsumer.class), anyInt());
 
     return span;
   }