Add is_remote_parent span flags to OTLP exported Spans and SpanLinks

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

api/all/src/main/java/io/opentelemetry/api/trace/ImmutableTraceFlags.java

@@ -14,6 +14,9 @@ final class ImmutableTraceFlags implements TraceFlags {
   private static final ImmutableTraceFlags[] INSTANCES = buildInstances();
   // Bit to represent whether trace is sampled or not.
   private static final byte SAMPLED_BIT = 0x01;
+  static final int CONTEXT_HAS_IS_REMOTE_BIT = 0x00000100;
+  static final int CONTEXT_IS_REMOTE_BIT = 0x00000200;
+  static final int CONTEXT_IS_REMOTE_MASK = CONTEXT_HAS_IS_REMOTE_BIT | CONTEXT_IS_REMOTE_BIT;
 
   static final ImmutableTraceFlags DEFAULT = fromByte((byte) 0x00);
   static final ImmutableTraceFlags SAMPLED = fromByte(SAMPLED_BIT);
@@ -65,6 +68,15 @@ public byte asByte() {
     return this.byteRep;
   }
 
+  @Override
+  public int withParentIsRemoteFlags(boolean isParentRemote) {
+    if (isParentRemote) {
+      return (this.byteRep & 0xff) | CONTEXT_IS_REMOTE_MASK;
+    } else {
+      return (this.byteRep & 0xff) | CONTEXT_HAS_IS_REMOTE_BIT;
+    }
+  }
+
   @Override
   public String toString() {
     return asHex();

api/all/src/main/java/io/opentelemetry/api/trace/TraceFlags.java

@@ -44,6 +44,28 @@ static TraceFlags getSampled() {
     return ImmutableTraceFlags.SAMPLED;
   }
 
+  /**
+   * Returns the int (fixed32) representation of the 4 bytes flags with the
+   * has_parent_context_is_remote flag bit on.
+   *
+   * @return the int (fixed32) representation of the 4 bytes flags with the *
+   *     has_parent_context_is_remote flag bit on.
+   */
+  static int getHasParentIsRemote() {
+    return ImmutableTraceFlags.CONTEXT_HAS_IS_REMOTE_BIT;
+  }
+
+  /**
+   * Returns the int (fixed32) representation of the 4 bytes flags with the
+   * has_parent_context_is_remote and parent_context_is_remote flag bits on.
+   *
+   * @return the int (fixed32) representation of the 4 bytes flags with the
+   *     has_parent_context_is_remote and parent_context_is_remote flag bits on.
+   */
+  static int getParentIsRemote() {
+    return ImmutableTraceFlags.CONTEXT_IS_REMOTE_MASK;
+  }
+
   /**
    * Returns the {@link TraceFlags} converted from the given lowercase hex (base16) representation.
    *
@@ -89,4 +111,14 @@ static TraceFlags fromByte(byte traceFlagsByte) {
    * @return the byte representation of the {@link TraceFlags}.
    */
   byte asByte();
+
+  /**
+   * Returns the int (fixed32) representation of this {@link TraceFlags} enriched with the flags
+   * indicating a remote parent.
+   *
+   * @param isParentRemote indicates whether the parent context is remote
+   * @return the int (fixed32) representation of this {@link TraceFlags} enriched with the flags
+   *     indicating a remote parent.
+   */
+  int withParentIsRemoteFlags(boolean isParentRemote);
 }

api/all/src/test/java/io/opentelemetry/api/trace/TraceFlagsTest.java

@@ -43,4 +43,17 @@ void toFromByte() {
       assertThat(TraceFlags.fromByte((byte) i).asByte()).isEqualTo((byte) i);
     }
   }
+
+  @Test
+  void withParentIsRemoteFlags() {
+    assertThat(TraceFlags.fromByte((byte) 0xff).withParentIsRemoteFlags(false)).isEqualTo(0x1ff);
+    assertThat(TraceFlags.fromByte((byte) 0x01).withParentIsRemoteFlags(false)).isEqualTo(0x101);
+    assertThat(TraceFlags.fromByte((byte) 0x05).withParentIsRemoteFlags(false)).isEqualTo(0x105);
+    assertThat(TraceFlags.fromByte((byte) 0x00).withParentIsRemoteFlags(false)).isEqualTo(0x100);
+
+    assertThat(TraceFlags.fromByte((byte) 0xff).withParentIsRemoteFlags(true)).isEqualTo(0x3ff);
+    assertThat(TraceFlags.fromByte((byte) 0x01).withParentIsRemoteFlags(true)).isEqualTo(0x301);
+    assertThat(TraceFlags.fromByte((byte) 0x05).withParentIsRemoteFlags(true)).isEqualTo(0x305);
+    assertThat(TraceFlags.fromByte((byte) 0x00).withParentIsRemoteFlags(true)).isEqualTo(0x300);
+  }
 }

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

@@ -28,6 +28,7 @@ final class SpanLinkMarshaler extends MarshalerWithSize {
   private final KeyValueMarshaler[] attributeMarshalers;
   private final int droppedAttributesCount;
   private final TraceFlags traceFlags;
+  private final boolean isLinkContextRemote;
 
   static SpanLinkMarshaler[] createRepeated(List<LinkData> links) {
     if (links.isEmpty()) {
@@ -50,13 +51,15 @@ static SpanLinkMarshaler create(LinkData link) {
         traceState.isEmpty()
             ? EMPTY_BYTES
             : encodeTraceState(traceState).getBytes(StandardCharsets.UTF_8);
+
     return new SpanLinkMarshaler(
         link.getSpanContext().getTraceId(),
         link.getSpanContext().getSpanId(),
         link.getSpanContext().getTraceFlags(),
         traceStateUtf8,
         KeyValueMarshaler.createForAttributes(link.getAttributes()),
-        link.getTotalAttributeCount() - link.getAttributes().size());
+        link.getTotalAttributeCount() - link.getAttributes().size(),
+        link.getSpanContext().isRemote());
   }
 
   private SpanLinkMarshaler(
@@ -65,21 +68,24 @@ private SpanLinkMarshaler(
       TraceFlags traceFlags,
       byte[] traceStateUtf8,
       KeyValueMarshaler[] attributeMarshalers,
-      int droppedAttributesCount) {
+      int droppedAttributesCount,
+      boolean isLinkContextRemote) {
     super(
         calculateSize(
             traceId,
             spanId,
             traceFlags,
             traceStateUtf8,
             attributeMarshalers,
-            droppedAttributesCount));
+            droppedAttributesCount,
+            isLinkContextRemote));
     this.traceId = traceId;
     this.spanId = spanId;
     this.traceFlags = traceFlags;
     this.traceStateUtf8 = traceStateUtf8;
     this.attributeMarshalers = attributeMarshalers;
     this.droppedAttributesCount = droppedAttributesCount;
+    this.isLinkContextRemote = isLinkContextRemote;
   }
 
   @Override
@@ -89,7 +95,8 @@ 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.withParentIsRemoteFlags(isLinkContextRemote));
   }
 
   private static int calculateSize(
@@ -98,14 +105,17 @@ private static int calculateSize(
       TraceFlags flags,
       byte[] traceStateUtf8,
       KeyValueMarshaler[] attributeMarshalers,
-      int droppedAttributesCount) {
+      int droppedAttributesCount,
+      boolean isLinkContextRemote) {
     int size = 0;
     size += MarshalerUtil.sizeTraceId(Span.Link.TRACE_ID, traceId);
     size += MarshalerUtil.sizeSpanId(Span.Link.SPAN_ID, spanId);
     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.withParentIsRemoteFlags(isLinkContextRemote));
     return size;
   }
 }

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

@@ -39,6 +39,7 @@ final class SpanMarshaler extends MarshalerWithSize {
   private final int droppedLinksCount;
   private final SpanStatusMarshaler spanStatusMarshaler;
   private final TraceFlags flags;
+  private final boolean isParentContextRemote;
 
   // Because SpanMarshaler is always part of a repeated field, it cannot return "null".
   static SpanMarshaler create(SpanData spanData) {
@@ -75,7 +76,8 @@ static SpanMarshaler create(SpanData spanData) {
         spanLinkMarshalers,
         spanData.getTotalRecordedLinks() - spanData.getLinks().size(),
         SpanStatusMarshaler.create(spanData.getStatus()),
-        spanData.getSpanContext().getTraceFlags());
+        spanData.getSpanContext().getTraceFlags(),
+        spanData.getParentSpanContext().isRemote());
   }
 
   private SpanMarshaler(
@@ -94,7 +96,8 @@ private SpanMarshaler(
       SpanLinkMarshaler[] spanLinkMarshalers,
       int droppedLinksCount,
       SpanStatusMarshaler spanStatusMarshaler,
-      TraceFlags flags) {
+      TraceFlags flags,
+      boolean isParentContextRemote) {
     super(
         calculateSize(
             traceId,
@@ -112,7 +115,8 @@ private SpanMarshaler(
             spanLinkMarshalers,
             droppedLinksCount,
             spanStatusMarshaler,
-            flags));
+            flags,
+            isParentContextRemote));
     this.traceId = traceId;
     this.spanId = spanId;
     this.traceStateUtf8 = traceStateUtf8;
@@ -129,6 +133,7 @@ private SpanMarshaler(
     this.droppedLinksCount = droppedLinksCount;
     this.spanStatusMarshaler = spanStatusMarshaler;
     this.flags = flags;
+    this.isParentContextRemote = isParentContextRemote;
   }
 
   @Override
@@ -154,7 +159,7 @@ 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.withParentIsRemoteFlags(isParentContextRemote));
   }
 
   private static int calculateSize(
@@ -173,7 +178,8 @@ private static int calculateSize(
       SpanLinkMarshaler[] spanLinkMarshalers,
       int droppedLinksCount,
       SpanStatusMarshaler spanStatusMarshaler,
-      TraceFlags flags) {
+      TraceFlags flags,
+      boolean isParentContextRemote) {
     int size = 0;
     size += MarshalerUtil.sizeTraceId(Span.TRACE_ID, traceId);
     size += MarshalerUtil.sizeSpanId(Span.SPAN_ID, spanId);
@@ -196,7 +202,8 @@ 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.withParentIsRemoteFlags(isParentContextRemote));
     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 +154,8 @@ 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(
+            (SPAN_CONTEXT.getTraceFlags().asByte() & 0xff) | TraceFlags.getHasParentIsRemote());
     assertThat(protoSpan.getTraceState()).isEqualTo(TRACE_STATE_VALUE);
     assertThat(protoSpan.getParentSpanId().toByteArray()).isEqualTo(new byte[] {});
     assertThat(protoSpan.getName()).isEqualTo("GET /api/endpoint");
@@ -227,14 +234,47 @@ 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() & 0xff)
+                        | TraceFlags.getHasParentIsRemote())
                 .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((SPAN_CONTEXT.getTraceFlags().asByte() & 0xff) | TraceFlags.getParentIsRemote());
+    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))
@@ -318,11 +358,28 @@ void toProtoSpanLink_WithoutAttributes() {
             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() & 0xff)
+                        | TraceFlags.getHasParentIsRemote())
                 .setTraceState(TRACE_STATE_VALUE)
                 .build());
   }
 
+  @Test
+  void toProtoSpanLink_WithRemoteContext() {
+    assertThat(
+            parse(
+                Span.Link.getDefaultInstance(),
+                SpanLinkMarshaler.create(LinkData.create(PARENT_SPAN_CONTEXT))))
+        .isEqualTo(
+            Span.Link.newBuilder()
+                .setTraceId(ByteString.copyFrom(TRACE_ID_BYTES))
+                .setSpanId(ByteString.copyFrom(PARENT_SPAN_ID_BYTES))
+                .setFlags(
+                    (SPAN_CONTEXT.getTraceFlags().asByte() & 0xff) | TraceFlags.getParentIsRemote())
+                .build());
+  }
+
   @Test
   void toProtoSpanLink_WithAttributes() {
     assertThat(
@@ -335,7 +392,9 @@ void toProtoSpanLink_WithAttributes() {
             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() & 0xff)
+                        | TraceFlags.getHasParentIsRemote())
                 .setTraceState(TRACE_STATE_VALUE)
                 .addAttributes(
                     KeyValue.newBuilder()