chore: added functionality for constructing full trace flags with lower bits as well

Author: nikhilmantri0902

experimental/packages/otlp-transformer/src/trace/internal.ts

@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import type { Link, SpanContext } from '@opentelemetry/api';
+import type { Link } from '@opentelemetry/api';
 import { Resource } from '@opentelemetry/resources';
 import type { ReadableSpan, TimedEvent } from '@opentelemetry/sdk-trace-base';
 import type { Encoder } from '../common/utils';
@@ -39,12 +39,13 @@ const SPAN_FLAGS_CONTEXT_HAS_IS_REMOTE_MASK = 0x100;
 const SPAN_FLAGS_CONTEXT_IS_REMOTE_MASK = 0x200;
 
 /**
- * Builds span flags based on the parent span context's isRemote property.
- * This follows the OTLP specification for span flags.
+ * Builds the 32-bit span flags value combining the low 8-bit W3C TraceFlags
+ * with the HAS_IS_REMOTE and IS_REMOTE bits according to the OTLP spec.
  */
-function buildSpanFlags(parentSpanContext?: SpanContext): number {
-  let flags = SPAN_FLAGS_CONTEXT_HAS_IS_REMOTE_MASK;
-  if (parentSpanContext?.isRemote) {
+function buildSpanFlagsFrom(traceFlags: number, isRemote?: boolean): number {
+  // low 8 bits are W3C TraceFlags (e.g., sampled)
+  let flags = (traceFlags & 0xff) | SPAN_FLAGS_CONTEXT_HAS_IS_REMOTE_MASK;
+  if (isRemote) {
     flags |= SPAN_FLAGS_CONTEXT_IS_REMOTE_MASK;
   }
   return flags;
@@ -77,7 +78,7 @@ export function sdkSpanToOtlpSpan(span: ReadableSpan, encoder: Encoder): ISpan {
     },
     links: span.links.map(link => toOtlpLink(link, encoder)),
     droppedLinksCount: span.droppedLinksCount,
-    flags: buildSpanFlags(span.parentSpanContext),
+    flags: buildSpanFlagsFrom(ctx.traceFlags, span.parentSpanContext?.isRemote),
   };
 }
 
@@ -88,7 +89,7 @@ export function toOtlpLink(link: Link, encoder: Encoder): ILink {
     traceId: encoder.encodeSpanContext(link.context.traceId),
     traceState: link.context.traceState?.serialize(),
     droppedAttributesCount: link.droppedAttributesCount || 0,
-    flags: buildSpanFlags(link.context),
+    flags: buildSpanFlagsFrom(link.context.traceFlags, link.context.isRemote),
   };
 }
 

experimental/packages/otlp-transformer/test/trace.test.ts

@@ -97,7 +97,7 @@ function createExpectedSpanJson(options: OtlpEncodingOptions) {
                         },
                       },
                     ],
-                    flags: 0x100, // SPAN_FLAGS_CONTEXT_HAS_IS_REMOTE_MASK
+                    flags: 0x101, // TraceFlags (0x01) | HAS_IS_REMOTE
                   },
                 ],
                 startTimeUnixNano: startTime,
@@ -130,7 +130,7 @@ function createExpectedSpanJson(options: OtlpEncodingOptions) {
                   code: EStatusCode.STATUS_CODE_OK,
                   message: undefined,
                 },
-                flags: 0x100, // SPAN_FLAGS_CONTEXT_HAS_IS_REMOTE_MASK
+                flags: 0x101, // TraceFlags (0x01) | HAS_IS_REMOTE
               },
             ],
             schemaUrl: 'http://url.to.schema',
@@ -189,7 +189,7 @@ function createExpectedSpanProtobuf() {
                         },
                       },
                     ],
-                    flags: 0x100, // SPAN_FLAGS_CONTEXT_HAS_IS_REMOTE_MASK
+                    flags: 0x101, // TraceFlags (0x01) | HAS_IS_REMOTE
                   },
                 ],
                 startTimeUnixNano: startTime,
@@ -221,7 +221,7 @@ function createExpectedSpanProtobuf() {
                 status: {
                   code: EStatusCode.STATUS_CODE_OK,
                 },
-                flags: 0x100, // SPAN_FLAGS_CONTEXT_HAS_IS_REMOTE_MASK
+                flags: 0x101, // TraceFlags (0x01) | HAS_IS_REMOTE
               },
             ],
             schemaUrl: 'http://url.to.schema',
@@ -580,16 +580,16 @@ describe('Trace', () => {
   });
 
   describe('span flags', () => {
-    it('sets flags to 0x100 for local parent span context', () => {
+    it('sets flags to 0x101 for local parent span context', () => {
       const exportRequest = createExportTraceServiceRequest([span], {
         useHex: true,
       });
       assert.ok(exportRequest);
       const spanFlags = exportRequest.resourceSpans?.[0].scopeSpans[0].spans?.[0].flags;
-      assert.strictEqual(spanFlags, 0x100); // SPAN_FLAGS_CONTEXT_HAS_IS_REMOTE_MASK
+      assert.strictEqual(spanFlags, 0x101); // TraceFlags (0x01) | HAS_IS_REMOTE
     });
 
-    it('sets flags to 0x300 for remote parent span context', () => {
+    it('sets flags to 0x301 for remote parent span context', () => {
       // Create a span with a remote parent context
       const remoteParentSpanContext = {
         spanId: '0000000000000001',
@@ -608,19 +608,19 @@ describe('Trace', () => {
       });
       assert.ok(exportRequest);
       const spanFlags = exportRequest.resourceSpans?.[0].scopeSpans[0].spans?.[0].flags;
-      assert.strictEqual(spanFlags, 0x300); // SPAN_FLAGS_CONTEXT_HAS_IS_REMOTE_MASK | SPAN_FLAGS_CONTEXT_IS_REMOTE_MASK
+      assert.strictEqual(spanFlags, 0x301); // TraceFlags (0x01) | HAS_IS_REMOTE | IS_REMOTE
     });
 
-    it('sets flags to 0x100 for links with local context', () => {
+    it('sets flags to 0x101 for links with local context', () => {
       const exportRequest = createExportTraceServiceRequest([span], {
         useHex: true,
       });
       assert.ok(exportRequest);
       const linkFlags = exportRequest.resourceSpans?.[0].scopeSpans[0].spans?.[0].links?.[0].flags;
-      assert.strictEqual(linkFlags, 0x100); // SPAN_FLAGS_CONTEXT_HAS_IS_REMOTE_MASK
+      assert.strictEqual(linkFlags, 0x101); // TraceFlags (0x01) | HAS_IS_REMOTE
     });
 
-    it('sets flags to 0x300 for links with remote context', () => {
+    it('sets flags to 0x301 for links with remote context', () => {
       // Create a span with a remote link context
       const remoteLinkContext = {
         spanId: '0000000000000003',
@@ -645,7 +645,7 @@ describe('Trace', () => {
       });
       assert.ok(exportRequest);
       const linkFlags = exportRequest.resourceSpans?.[0].scopeSpans[0].spans?.[0].links?.[0].flags;
-      assert.strictEqual(linkFlags, 0x300); // SPAN_FLAGS_CONTEXT_HAS_IS_REMOTE_MASK | SPAN_FLAGS_CONTEXT_IS_REMOTE_MASK
+      assert.strictEqual(linkFlags, 0x301); // TraceFlags (0x01) | HAS_IS_REMOTE | IS_REMOTE
     });
   });
 });