From 3daa168183a490d055029bdcee3dec613d3dea1b Mon Sep 17 00:00:00 2001
From: Harry <harryryu@amazon.com>
Date: Fri, 7 Feb 2025 10:16:36 -0800
Subject: [PATCH] Remove spans with ec2 metadata ip address from metrics

---
 .../src/aws-span-metrics-processor.ts         | 19 +++++++++++----
 .../test/aws-span-metrics-processor.test.ts   | 23 +++++++++++++++++++
 2 files changed, 38 insertions(+), 4 deletions(-)

diff --git a/aws-distro-opentelemetry-node-autoinstrumentation/src/aws-span-metrics-processor.ts b/aws-distro-opentelemetry-node-autoinstrumentation/src/aws-span-metrics-processor.ts
index 48e1f59d..7da0a0a2 100644
--- a/aws-distro-opentelemetry-node-autoinstrumentation/src/aws-span-metrics-processor.ts
+++ b/aws-distro-opentelemetry-node-autoinstrumentation/src/aws-span-metrics-processor.ts
@@ -5,8 +5,9 @@ import { AttributeValue, Attributes, Context, Histogram, SpanStatusCode } from '
 import { Resource } from '@opentelemetry/resources';
 import { ReadableSpan, Span, SpanProcessor } from '@opentelemetry/sdk-trace-base';
 import { SEMATTRS_HTTP_STATUS_CODE } from '@opentelemetry/semantic-conventions';
-import { AttributeMap, MetricAttributeGenerator } from './metric-attribute-generator';
+import { AttributeMap, DEPENDENCY_METRIC, MetricAttributeGenerator } from './metric-attribute-generator';
 import { ForceFlushFunction } from './aws-span-processing-util';
+import { AWS_ATTRIBUTE_KEYS } from './aws-attribute-keys';
 
 /**
  * This processor will generate metrics based on span data. It depends on a
@@ -33,6 +34,10 @@ export class AwsSpanMetricsProcessor implements SpanProcessor {
   private FAULT_CODE_LOWER_BOUND: number = 500;
   private FAULT_CODE_UPPER_BOUND: number = 599;
 
+  // EC2 Metadata API IP Address
+  // https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/instancedata-data-retrieval.html#instancedata-inside-access
+  private EC2_METADATA_API_IP: string = '169.254.169.254';
+
   // Metric instruments
   private errorHistogram: Histogram;
   private faultHistogram: Histogram;
@@ -83,8 +88,10 @@ export class AwsSpanMetricsProcessor implements SpanProcessor {
   public onEnd(span: ReadableSpan): void {
     const attributeMap: AttributeMap = this.generator.generateMetricAttributeMapFromSpan(span, this.resource);
 
-    for (const attribute in attributeMap) {
-      this.recordMetrics(span, attributeMap[attribute]);
+    if (!this.isEc2MetadataApiSpan(attributeMap)) {
+      for (const attribute in attributeMap) {
+        this.recordMetrics(span, attributeMap[attribute]);
+      }
     }
   }
 
@@ -143,4 +150,8 @@ export class AwsSpanMetricsProcessor implements SpanProcessor {
   public forceFlush(): Promise<void> {
     return this.forceFlushFunction();
   }
-}
+
+  private isEc2MetadataApiSpan(attributeMap: AttributeMap): boolean {
+    return attributeMap[DEPENDENCY_METRIC]?.[AWS_ATTRIBUTE_KEYS.AWS_REMOTE_SERVICE] === this.EC2_METADATA_API_IP;
+  }
+}
\ No newline at end of file
diff --git a/aws-distro-opentelemetry-node-autoinstrumentation/test/aws-span-metrics-processor.test.ts b/aws-distro-opentelemetry-node-autoinstrumentation/test/aws-span-metrics-processor.test.ts
index 9409eee1..9f4845ae 100644
--- a/aws-distro-opentelemetry-node-autoinstrumentation/test/aws-span-metrics-processor.test.ts
+++ b/aws-distro-opentelemetry-node-autoinstrumentation/test/aws-span-metrics-processor.test.ts
@@ -397,6 +397,22 @@ describe('AwsSpanMetricsProcessorTest', () => {
     validateMetricsGeneratedForStatusDataOk(600, ExpectedStatusMetric.NEITHER);
   });
 
+  it('testOnEndMetricsGenerationFromEc2MetadataApi', () => {
+    const spanAttributes: Attributes = { [AWS_ATTRIBUTE_KEYS.AWS_REMOTE_SERVICE]: '169.254.169.254' };
+    const readableSpanMock: ReadableSpan = buildReadableSpanMock(
+      spanAttributes,
+      SpanKind.CLIENT,
+      INVALID_SPAN_CONTEXT,
+      { code: SpanStatusCode.UNSET }
+    );
+    const metricAttributesMap: AttributeMap = buildEc2MetadataApiMetricAttributes();
+    configureMocksForOnEnd(readableSpanMock, metricAttributesMap);
+    awsSpanMetricsProcessor.onEnd(readableSpanMock);
+    sinon.assert.notCalled(errorHistogramMockRecord);
+    sinon.assert.notCalled(faultHistogramMockRecord);
+    sinon.assert.notCalled(latencyHistogramMockRecord);
+  });
+
   function buildSpanAttributes(containsAttribute: boolean): Attributes {
     if (containsAttribute) {
       return { 'original key': 'original value' };
@@ -421,6 +437,13 @@ describe('AwsSpanMetricsProcessorTest', () => {
     return attributesMap;
   }
 
+  function buildEc2MetadataApiMetricAttributes(): AttributeMap {
+    const attributesMap: AttributeMap = {};
+    const attributes: Attributes = { [AWS_ATTRIBUTE_KEYS.AWS_REMOTE_SERVICE]: '169.254.169.254' };
+    attributesMap[DEPENDENCY_METRIC] = attributes;
+    return attributesMap;
+  }
+
   function buildReadableSpanMock(
     spanAttributes: Attributes,
     spanKind: SpanKind = SpanKind.SERVER,