track persistent caching usage (#76996)

packages/next/src/build/index.ts

@@ -206,6 +206,7 @@ import {
 } from '../server/lib/router-utils/build-prefetch-segment-data-route'
 
 import { turbopackBuild } from './turbopack-build'
+import { isPersistentCachingEnabled } from '../shared/lib/turbopack/utils'
 import { inlineStaticEnv, populateStaticEnv } from '../lib/inline-static-env'
 
 type Fallback = null | boolean | string
@@ -2476,6 +2477,10 @@ export default async function build(
           featureName: 'experimental/ppr',
           invocationCount: config.experimental.ppr ? 1 : 0,
         },
+        {
+          featureName: 'turbopackPersistentCaching',
+          invocationCount: isPersistentCachingEnabled(config) ? 1 : 0,
+        },
       ]
       telemetry.record(
         features.map((feature) => {

packages/next/src/server/lib/router-utils/setup-dev-bundler.ts

@@ -26,7 +26,10 @@ import type { Telemetry } from '../../../telemetry/storage'
 import type { IncomingMessage, ServerResponse } from 'http'
 import loadJsConfig from '../../../build/load-jsconfig'
 import { createValidFileMatcher } from '../find-page-file'
-import { eventCliSession } from '../../../telemetry/events'
+import {
+  EVENT_BUILD_FEATURE_USAGE,
+  eventCliSession,
+} from '../../../telemetry/events'
 import { getDefineEnv } from '../../../build/webpack/plugins/define-env-plugin'
 import { getSortedRoutes } from '../../../shared/lib/router/utils'
 import {
@@ -73,6 +76,7 @@ import { createEnvDefinitions } from '../experimental/create-env-definitions'
 import { JsConfigPathsPlugin } from '../../../build/webpack/plugins/jsconfig-paths-plugin'
 import { store as consoleStore } from '../../../build/output/store'
 import {
+  isPersistentCachingEnabled,
   ModuleBuildError,
   TurbopackInternalError,
 } from '../../../shared/lib/turbopack/utils'
@@ -996,6 +1000,16 @@ export async function setupDevBundler(opts: SetupOpts) {
       }
     )
   )
+
+  // Track build features for dev server here:
+  opts.telemetry.record({
+    eventName: EVENT_BUILD_FEATURE_USAGE,
+    payload: {
+      featureName: 'turbopackPersistentCaching',
+      invocationCount: isPersistentCachingEnabled(opts.nextConfig) ? 1 : 0,
+    },
+  })
+
   return result
 }
 

packages/next/src/telemetry/events/build.ts

@@ -178,6 +178,7 @@ export type EventBuildFeatureUsage = {
     | 'esmExternals'
     | 'webpackPlugins'
     | UseCacheTrackerKey
+    | 'turbopackPersistentCaching'
   invocationCount: number
 }
 export function eventBuildFeatureUsage(

test/integration/telemetry/next.config.persistent-cache

@@ -0,0 +1,7 @@
+module.exports = {
+  experimental: {
+    turbo: {
+      unstablePersistentCaching: true
+    }
+  }
+} 

test/integration/telemetry/test/config.test.js

@@ -6,10 +6,10 @@ import {
   launchApp,
   nextBuild,
   nextLint,
+  waitFor,
 } from 'next-test-utils'
 import fs from 'fs-extra'
 import path from 'path'
-
 const appDir = path.join(__dirname, '..')
 
 describe('config telemetry', () => {
@@ -761,6 +761,81 @@ describe('config telemetry', () => {
           })
         }
       )
+
+      it('emits telemetry for persistent cache in build mode', async () => {
+        await fs.rename(
+          path.join(appDir, 'next.config.persistent-cache'),
+          path.join(appDir, 'next.config.js')
+        )
+
+        try {
+          const { stderr } = await nextBuild(appDir, [], {
+            stderr: true,
+            env: { NEXT_TELEMETRY_DEBUG: 1 },
+          })
+
+          try {
+            const featureUsageEvents = findAllTelemetryEvents(
+              stderr,
+              'NEXT_BUILD_FEATURE_USAGE'
+            )
+            expect(featureUsageEvents).toContainEqual({
+              featureName: 'turbopackPersistentCaching',
+              invocationCount: 1,
+            })
+          } catch (err) {
+            require('console').error('failing stderr', stderr, err)
+            throw err
+          }
+        } finally {
+          await fs.rename(
+            path.join(appDir, 'next.config.js'),
+            path.join(appDir, 'next.config.persistent-cache')
+          )
+        }
+      })
+
+      it('emits telemetry for persistent cache in dev mode', async () => {
+        await fs.rename(
+          path.join(appDir, 'next.config.persistent-cache'),
+          path.join(appDir, 'next.config.js')
+        )
+
+        let app
+        let stderr = ''
+
+        try {
+          app = await launchApp(appDir, await findPort(), {
+            env: { NEXT_TELEMETRY_DEBUG: 1 },
+            onStderr(msg) {
+              stderr += msg || ''
+            },
+          })
+
+          await waitFor(2000)
+
+          const featureUsageEvents = findAllTelemetryEvents(
+            stderr,
+            'NEXT_BUILD_FEATURE_USAGE'
+          )
+
+          expect(featureUsageEvents).toContainEqual({
+            featureName: 'turbopackPersistentCaching',
+            invocationCount: 1,
+          })
+        } catch (err) {
+          require('console').error('failing stderr', err)
+          throw err
+        } finally {
+          if (app) {
+            await killApp(app)
+          }
+          await fs.rename(
+            path.join(appDir, 'next.config.js'),
+            path.join(appDir, 'next.config.persistent-cache')
+          )
+        }
+      })
     }
   )
 })