Add is_remote_parent span flags to OTLP exported Spans and SpanLinks

Signed-off-by: Alexander Wert <alexander.wert@elastic.co>

exporters/otlp/common/src/main/java/io/opentelemetry/exporter/internal/otlp/traces/ProtoSpanFlagsUtil.java

@@ -0,0 +1,27 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.exporter.internal.otlp.traces;
+
+import io.opentelemetry.api.trace.SpanContext;
+
+public final class ProtoSpanFlagsUtil {
+
+  private ProtoSpanFlagsUtil() {}
+
+  public static final int SPAN_FLAGS_CONTEXT_HAS_IS_REMOTE_MASK = 0x00000100;
+  public static final int SPAN_FLAGS_CONTEXT_IS_REMOTE_MASK = 0x00000200;
+
+  static int getFullSpanFlags(byte w3cTraceflags, SpanContext parentContext) {
+    int flags = w3cTraceflags;
+
+    flags = flags | SPAN_FLAGS_CONTEXT_HAS_IS_REMOTE_MASK;
+    if (parentContext.isRemote()) {
+      flags = flags | SPAN_FLAGS_CONTEXT_IS_REMOTE_MASK;
+    }
+
+    return flags;
+  }
+}

exporters/otlp/common/src/main/java/io/opentelemetry/exporter/internal/otlp/traces/SpanLinkMarshaler.java

@@ -7,7 +7,6 @@
 
 import static io.opentelemetry.api.trace.propagation.internal.W3CTraceContextEncoding.encodeTraceState;
 
-import io.opentelemetry.api.trace.TraceFlags;
 import io.opentelemetry.api.trace.TraceState;
 import io.opentelemetry.exporter.internal.marshal.MarshalerUtil;
 import io.opentelemetry.exporter.internal.marshal.MarshalerWithSize;
@@ -27,7 +26,7 @@ final class SpanLinkMarshaler extends MarshalerWithSize {
   private final byte[] traceStateUtf8;
   private final KeyValueMarshaler[] attributeMarshalers;
   private final int droppedAttributesCount;
-  private final TraceFlags traceFlags;
+  private final int traceFlags;
 
   static SpanLinkMarshaler[] createRepeated(List<LinkData> links) {
     if (links.isEmpty()) {
@@ -50,10 +49,14 @@ static SpanLinkMarshaler create(LinkData link) {
         traceState.isEmpty()
             ? EMPTY_BYTES
             : encodeTraceState(traceState).getBytes(StandardCharsets.UTF_8);
+    int flags =
+        ProtoSpanFlagsUtil.getFullSpanFlags(
+            link.getSpanContext().getTraceFlags().asByte(), link.getSpanContext());
+
     return new SpanLinkMarshaler(
         link.getSpanContext().getTraceId(),
         link.getSpanContext().getSpanId(),
-        link.getSpanContext().getTraceFlags(),
+        flags,
         traceStateUtf8,
         KeyValueMarshaler.createForAttributes(link.getAttributes()),
         link.getTotalAttributeCount() - link.getAttributes().size());
@@ -62,7 +65,7 @@ static SpanLinkMarshaler create(LinkData link) {
   private SpanLinkMarshaler(
       String traceId,
       String spanId,
-      TraceFlags traceFlags,
+      int traceFlags,
       byte[] traceStateUtf8,
       KeyValueMarshaler[] attributeMarshalers,
       int droppedAttributesCount) {
@@ -89,13 +92,13 @@ public void writeTo(Serializer output) throws IOException {
     output.serializeString(Span.Link.TRACE_STATE, traceStateUtf8);
     output.serializeRepeatedMessage(Span.Link.ATTRIBUTES, attributeMarshalers);
     output.serializeUInt32(Span.Link.DROPPED_ATTRIBUTES_COUNT, droppedAttributesCount);
-    output.serializeByteAsFixed32(Span.Link.FLAGS, traceFlags.asByte());
+    output.serializeFixed32(Span.Link.FLAGS, traceFlags);
   }
 
   private static int calculateSize(
       String traceId,
       String spanId,
-      TraceFlags flags,
+      int flags,
       byte[] traceStateUtf8,
       KeyValueMarshaler[] attributeMarshalers,
       int droppedAttributesCount) {
@@ -105,7 +108,7 @@ private static int calculateSize(
     size += MarshalerUtil.sizeBytes(Span.Link.TRACE_STATE, traceStateUtf8);
     size += MarshalerUtil.sizeRepeatedMessage(Span.Link.ATTRIBUTES, attributeMarshalers);
     size += MarshalerUtil.sizeUInt32(Span.Link.DROPPED_ATTRIBUTES_COUNT, droppedAttributesCount);
-    size += MarshalerUtil.sizeByteAsFixed32(Span.Link.FLAGS, flags.asByte());
+    size += MarshalerUtil.sizeFixed32(Span.Link.FLAGS, flags);
     return size;
   }
 }

exporters/otlp/common/src/main/java/io/opentelemetry/exporter/internal/otlp/traces/SpanMarshaler.java

@@ -8,7 +8,6 @@
 import static io.opentelemetry.api.trace.propagation.internal.W3CTraceContextEncoding.encodeTraceState;
 
 import io.opentelemetry.api.trace.SpanKind;
-import io.opentelemetry.api.trace.TraceFlags;
 import io.opentelemetry.api.trace.TraceState;
 import io.opentelemetry.exporter.internal.marshal.MarshalerUtil;
 import io.opentelemetry.exporter.internal.marshal.MarshalerWithSize;
@@ -38,7 +37,7 @@ final class SpanMarshaler extends MarshalerWithSize {
   private final SpanLinkMarshaler[] spanLinkMarshalers;
   private final int droppedLinksCount;
   private final SpanStatusMarshaler spanStatusMarshaler;
-  private final TraceFlags flags;
+  private final int flags;
 
   // Because SpanMarshaler is always part of a repeated field, it cannot return "null".
   static SpanMarshaler create(SpanData spanData) {
@@ -59,6 +58,10 @@ static SpanMarshaler create(SpanData spanData) {
             ? EMPTY_BYTES
             : encodeTraceState(traceState).getBytes(StandardCharsets.UTF_8);
 
+    int flags =
+        ProtoSpanFlagsUtil.getFullSpanFlags(
+            spanData.getSpanContext().getTraceFlags().asByte(), spanData.getParentSpanContext());
+
     return new SpanMarshaler(
         spanData.getSpanContext().getTraceId(),
         spanData.getSpanContext().getSpanId(),
@@ -75,7 +78,7 @@ static SpanMarshaler create(SpanData spanData) {
         spanLinkMarshalers,
         spanData.getTotalRecordedLinks() - spanData.getLinks().size(),
         SpanStatusMarshaler.create(spanData.getStatus()),
-        spanData.getSpanContext().getTraceFlags());
+        flags);
   }
 
   private SpanMarshaler(
@@ -94,7 +97,7 @@ private SpanMarshaler(
       SpanLinkMarshaler[] spanLinkMarshalers,
       int droppedLinksCount,
       SpanStatusMarshaler spanStatusMarshaler,
-      TraceFlags flags) {
+      int flags) {
     super(
         calculateSize(
             traceId,
@@ -154,7 +157,7 @@ public void writeTo(Serializer output) throws IOException {
     output.serializeUInt32(Span.DROPPED_LINKS_COUNT, droppedLinksCount);
 
     output.serializeMessage(Span.STATUS, spanStatusMarshaler);
-    output.serializeByteAsFixed32(Span.FLAGS, flags.asByte());
+    output.serializeFixed32(Span.FLAGS, flags);
   }
 
   private static int calculateSize(
@@ -173,7 +176,7 @@ private static int calculateSize(
       SpanLinkMarshaler[] spanLinkMarshalers,
       int droppedLinksCount,
       SpanStatusMarshaler spanStatusMarshaler,
-      TraceFlags flags) {
+      int flags) {
     int size = 0;
     size += MarshalerUtil.sizeTraceId(Span.TRACE_ID, traceId);
     size += MarshalerUtil.sizeSpanId(Span.SPAN_ID, spanId);
@@ -196,7 +199,7 @@ private static int calculateSize(
     size += MarshalerUtil.sizeUInt32(Span.DROPPED_LINKS_COUNT, droppedLinksCount);
 
     size += MarshalerUtil.sizeMessage(Span.STATUS, spanStatusMarshaler);
-    size += MarshalerUtil.sizeByteAsFixed32(Span.FLAGS, flags.asByte());
+    size += MarshalerUtil.sizeFixed32(Span.FLAGS, flags);
     return size;
   }
 

exporters/otlp/common/src/test/java/io/opentelemetry/exporter/internal/otlp/traces/TraceRequestMarshalerTest.java

@@ -56,7 +56,9 @@ class TraceRequestMarshalerTest {
       new byte[] {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4};
   private static final String TRACE_ID = TraceId.fromBytes(TRACE_ID_BYTES);
   private static final byte[] SPAN_ID_BYTES = new byte[] {0, 0, 0, 0, 4, 3, 2, 1};
+  private static final byte[] PARENT_SPAN_ID_BYTES = new byte[] {0, 0, 0, 0, 5, 6, 7, 8};
   private static final String SPAN_ID = SpanId.fromBytes(SPAN_ID_BYTES);
+  private static final String PARENT_SPAN_ID = SpanId.fromBytes(PARENT_SPAN_ID_BYTES);
   private static final String TRACE_STATE_VALUE = "baz=qux,foo=bar";
   private static final SpanContext SPAN_CONTEXT =
       SpanContext.create(
@@ -65,6 +67,10 @@ class TraceRequestMarshalerTest {
           TraceFlags.getSampled(),
           TraceState.builder().put("foo", "bar").put("baz", "qux").build());
 
+  private static final SpanContext PARENT_SPAN_CONTEXT =
+      SpanContext.createFromRemoteParent(
+          TRACE_ID, PARENT_SPAN_ID, TraceFlags.getSampled(), TraceState.builder().build());
+
   @Test
   void toProtoResourceSpans() {
     ResourceSpansMarshaler[] resourceSpansMarshalers =
@@ -148,7 +154,9 @@ void toProtoSpan() {
     assertThat(protoSpan.getTraceId().toByteArray()).isEqualTo(TRACE_ID_BYTES);
     assertThat(protoSpan.getSpanId().toByteArray()).isEqualTo(SPAN_ID_BYTES);
     assertThat(protoSpan.getFlags())
-        .isEqualTo(((int) SPAN_CONTEXT.getTraceFlags().asByte()) & 0x00ff);
+        .isEqualTo(
+            (((int) SPAN_CONTEXT.getTraceFlags().asByte()) & 0x00ff)
+                | ProtoSpanFlagsUtil.SPAN_FLAGS_CONTEXT_HAS_IS_REMOTE_MASK);
     assertThat(protoSpan.getTraceState()).isEqualTo(TRACE_STATE_VALUE);
     assertThat(protoSpan.getParentSpanId().toByteArray()).isEqualTo(new byte[] {});
     assertThat(protoSpan.getName()).isEqualTo("GET /api/endpoint");
@@ -227,14 +235,50 @@ void toProtoSpan() {
             Span.Link.newBuilder()
                 .setTraceId(ByteString.copyFrom(TRACE_ID_BYTES))
                 .setSpanId(ByteString.copyFrom(SPAN_ID_BYTES))
-                .setFlags(SPAN_CONTEXT.getTraceFlags().asByte())
+                .setFlags(
+                    SPAN_CONTEXT.getTraceFlags().asByte()
+                        | ProtoSpanFlagsUtil.SPAN_FLAGS_CONTEXT_HAS_IS_REMOTE_MASK)
                 .setTraceState(encodeTraceState(SPAN_CONTEXT.getTraceState()))
                 .build());
     assertThat(protoSpan.getDroppedLinksCount()).isEqualTo(1); // 2 - 1
     assertThat(protoSpan.getStatus())
         .isEqualTo(Status.newBuilder().setCode(STATUS_CODE_OK).build());
   }
 
+  @Test
+  void toProtoSpan_withRemoteParent() {
+    Span protoSpan =
+        parse(
+            Span.getDefaultInstance(),
+            SpanMarshaler.create(
+                TestSpanData.builder()
+                    .setHasEnded(true)
+                    .setSpanContext(SPAN_CONTEXT)
+                    .setParentSpanContext(PARENT_SPAN_CONTEXT)
+                    .setName("GET /api/endpoint")
+                    .setKind(SpanKind.SERVER)
+                    .setStartEpochNanos(12345)
+                    .setEndEpochNanos(12349)
+                    .setStatus(StatusData.ok())
+                    .build()));
+
+    assertThat(protoSpan.getTraceId().toByteArray()).isEqualTo(TRACE_ID_BYTES);
+    assertThat(protoSpan.getSpanId().toByteArray()).isEqualTo(SPAN_ID_BYTES);
+    assertThat(protoSpan.getFlags())
+        .isEqualTo(
+            (((int) SPAN_CONTEXT.getTraceFlags().asByte()) & 0x00ff)
+                | ProtoSpanFlagsUtil.SPAN_FLAGS_CONTEXT_HAS_IS_REMOTE_MASK
+                | ProtoSpanFlagsUtil.SPAN_FLAGS_CONTEXT_IS_REMOTE_MASK);
+    assertThat(protoSpan.getTraceState()).isEqualTo(TRACE_STATE_VALUE);
+    assertThat(protoSpan.getParentSpanId().toByteArray()).isEqualTo(PARENT_SPAN_ID_BYTES);
+    assertThat(protoSpan.getName()).isEqualTo("GET /api/endpoint");
+    assertThat(protoSpan.getKind()).isEqualTo(SPAN_KIND_SERVER);
+    assertThat(protoSpan.getStartTimeUnixNano()).isEqualTo(12345);
+    assertThat(protoSpan.getEndTimeUnixNano()).isEqualTo(12349);
+    assertThat(protoSpan.getStatus())
+        .isEqualTo(Status.newBuilder().setCode(STATUS_CODE_OK).build());
+  }
+
   @Test
   void toProtoSpanKind() {
     assertThat(SpanMarshaler.toProtoSpanKind(SpanKind.INTERNAL))