[Serverless] Reset both inferred spans on each invocation.

pkg/serverless/invocationlifecycle/lifecycle.go

@@ -358,6 +358,7 @@ func (lp *LifecycleProcessor) newRequest(lambdaPayloadString []byte, startTime t
 			SpanID: inferredspan.GenerateSpanId(),
 		},
 	}
+	lp.requestHandler.inferredSpans[1] = nil
 	lp.requestHandler.triggerTags = make(map[string]string)
 	lp.requestHandler.triggerMetrics = make(map[string]float64)
 }

pkg/serverless/invocationlifecycle/lifecycle_test.go

@@ -1168,6 +1168,58 @@ func TestTriggerTypesLifecycleEventForSNSSQSNoDdContext(t *testing.T) {
 	assert.Equal(t, snsSpan.SpanID, sqsSpan.ParentID)
 }
 
+func TestTriggerTypesLifecycleEventForSNSSQSThenApiGateway(t *testing.T) {
+	// SNS-SQS creates two inferred spans. Ensure that then invoking the
+	// function with an event that should have just one inferred span (API
+	// Gateway) creates just one inferred span.
+	var tracePayload *api.Payload
+	testProcessor := &LifecycleProcessor{
+		DetectLambdaLibrary:  func() bool { return false },
+		ProcessTrace:         func(payload *api.Payload) { tracePayload = payload },
+		InferredSpansEnabled: true,
+	}
+
+	// SNS-SQS invocation
+	startInvocationTime := time.Now()
+	endInvocationTime := startInvocationTime.Add(time.Second)
+
+	startDetails := &InvocationStartDetails{
+		InvokeEventRawPayload: getEventFromFile("snssqs.json"),
+		InvokedFunctionARN:    "arn:aws:lambda:us-east-1:123456789012:function:my-function",
+		StartTime:             startInvocationTime,
+	}
+	endDetails := &InvocationEndDetails{
+		RequestID: "test-request-id",
+		EndTime:   endInvocationTime,
+	}
+
+	testProcessor.OnInvokeStart(startDetails)
+	testProcessor.OnInvokeEnd(endDetails)
+
+	spans := tracePayload.TracerPayload.Chunks[0].Spans
+	assert.Equal(t, 3, len(spans))
+
+	// API Gateway invocation
+	startInvocationTime = endInvocationTime
+	endInvocationTime = startInvocationTime.Add(time.Second)
+
+	startDetails = &InvocationStartDetails{
+		InvokeEventRawPayload: getEventFromFile("api-gateway.json"),
+		InvokedFunctionARN:    "arn:aws:lambda:us-east-1:123456789012:function:my-function",
+		StartTime:             startInvocationTime,
+	}
+	endDetails = &InvocationEndDetails{
+		RequestID: "test-request-id",
+		EndTime:   endInvocationTime,
+	}
+
+	testProcessor.OnInvokeStart(startDetails)
+	testProcessor.OnInvokeEnd(endDetails)
+
+	spans = tracePayload.TracerPayload.Chunks[0].Spans
+	assert.Equal(t, 2, len(spans))
+}
+
 func TestTriggerTypesLifecycleEventForSQSNoDdContext(t *testing.T) {
 
 	startInvocationTime := time.Now()