feat: Allowed undici error reporting to be disabled with feature flag undici_error_tracking (#2956)

Thanks for your contribution @Voziv 🎉

Author: Voziv

documentation/feature-flags.md

@@ -39,3 +39,9 @@ Any prerelease flags can be enabled or disabled in your agent config by adding a
 * Environment Variable: `NEW_RELIC_FEATURE_FLAG_OTEL_INSTRUMENTATION`
 * Description: Enables the creation of Transaction Trace segments and time slices metrics from opentelemetry spans. This will help drive New Relic UI experience for opentelemetry spans. 
 * **WARNING**: This is not feature complete and is not intended to be enabled yet.
+
+#### undici_error_tracking
+* Enabled by default: `true`
+* Configuration: `{ feature_flag: { undici_error_tracking: true|false }}`
+* Environment Variable: `NEW_RELIC_FEATURE_FLAG_UNDICI_ERROR_TRACKING`
+* Description: Enables the creation of errors when a request with undici fails. To disable tracking errors with undici, set the value to `false`.

lib/feature_flags.js

@@ -14,7 +14,8 @@ exports.prerelease = {
   promise_segments: false,
   reverse_naming_rules: false,
   unresolved_promise_cleanup: true,
-  kafkajs_instrumentation: false
+  kafkajs_instrumentation: false,
+  undici_error_tracking: true
 }
 
 // flags that are no longer used for released features

lib/instrumentation/undici.js

@@ -192,14 +192,15 @@ function requestHeadersHook(shim, { request, response }) {
  * @param {Error} params.error error from undici request
  */
 function endAndRestoreSegment(shim, { request, error }) {
+  const { config } = shim.agent
   const activeSegment = request[symbols.segment]
   const parentSegment = request[symbols.parentSegment]
   const tx = request[symbols.transaction]
   if (activeSegment) {
     activeSegment.end()
   }
 
-  if (error && tx) {
+  if (error && tx && config.feature_flag.undici_error_tracking === true) {
     handleError(shim, tx, error)
   }
 

test/unit/feature_flag.test.js

@@ -41,7 +41,8 @@ const used = [
   'undici_async_tracking',
   'aws_bedrock_instrumentation',
   'langchain_instrumentation',
-  'kafkajs_instrumentation'
+  'kafkajs_instrumentation',
+  'undici_error_tracking'
 ]
 
 test.beforeEach((ctx) => {

test/versioned/undici/requests.test.js

@@ -312,6 +312,26 @@ test('Undici request tests', async (t) => {
     })
   })
 
+  await t.test('should not log error when `feature_flag.undici_error_tracking` is false', async (t) => {
+    agent.config.feature_flag.undici_error_tracking = false
+    t.after(() => {
+      agent.config.feature_flag.undici_error_tracking = true
+    })
+    await helper.runInTransaction(agent, async (tx) => {
+      try {
+        await undici.request('https://invalidurl', {
+          path: '/foo',
+          method: 'GET'
+        })
+      } catch (err) {
+        assert.ok(err)
+        assertSegments(tx.trace, tx.trace.root, ['External/invalidurl/foo'], { exact: false })
+        assert.equal(tx.exceptions.length, 0)
+        tx.end()
+      }
+    })
+  })
+
   await t.test('segments should end on error', async () => {
     const socketEndServer = http.createServer(function badHandler(req) {
       req.socket.end()