Use the existing context if any to start the web spans (#1647)

* Use the existing context if any to start the web spans * unit tests
DataDog · Nov 2, 2021 · e2982f3 · e2982f3
1 parent fde5c0b
commit e2982f3
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Showing 2 changed files with 10 additions and 1 deletion.
diff --git a/packages/dd-trace/src/plugins/util/web.js b/packages/dd-trace/src/plugins/util/web.js
@@ -181,7 +181,7 @@ const web = {
 
   // Extract the parent span from the headers and start a new span as its child
   startChildSpan (tracer, name, headers) {
-    const childOf = tracer.extract(FORMAT_HTTP_HEADERS, headers)
+    const childOf = tracer.scope().active() || tracer.extract(FORMAT_HTTP_HEADERS, headers)
     const span = tracer.startSpan(name, { childOf })
 
     return span

diff --git a/packages/dd-trace/test/plugins/util/web.spec.js b/packages/dd-trace/test/plugins/util/web.spec.js
@@ -136,6 +136,15 @@ describe('plugins/util/web', () => {
         })
       })
 
+      it('should set the parent from the active context if any', () => {
+        tracer.trace('aws.lambda', parentSpan => {
+          web.instrument(tracer, config, req, res, 'test.request', span => {
+            expect(span.context()._traceId.toString(10)).to.equal(parentSpan.context()._traceId.toString(10))
+            expect(span.context()._parentId.toString(10)).to.equal(parentSpan.context()._spanId.toString(10))
+          })
+        })
+      })
+
       it('should set the service name', () => {
         config.service = 'custom'