Create file to control telemetry event firing

Author: heatlikeheatwave

packages/nextjs/src/app-router/server/ClerkProvider.tsx

@@ -69,6 +69,12 @@ export async function ClerkProvider(
 
   let output: ReactNode;
 
+  const detectKeylessEnvDrift = await import('../../server/keyless-telemetry.js').then(
+    mod => mod.detectKeylessEnvDrift,
+  );
+
+  await detectKeylessEnvDrift();
+
   if (shouldRunAsKeyless) {
     output = (
       <KeylessProvider

packages/nextjs/src/app-router/server/keyless-provider.tsx

@@ -6,7 +6,6 @@ import React from 'react';
 
 import { createClerkClientWithOptions } from '../../server/createClerkClient';
 import { collectKeylessMetadata, formatMetadataHeaders } from '../../server/keyless-custom-headers';
-import { detectKeylessEnvDrift } from '../../server/keyless-telemetry';
 import type { NextClerkProviderProps } from '../../types';
 import { canUseKeyless } from '../../utils/feature-flags';
 import { mergeNextClerkPropsWithEnv } from '../../utils/mergeNextClerkPropsWithEnv';
@@ -48,7 +47,10 @@ export const KeylessProvider = async (props: KeylessProviderProps) => {
     .then(mod => mod.createOrReadKeyless())
     .catch(() => null);
 
-  // Detect environment variable drift and fire telemetry events
+  const detectKeylessEnvDrift = await import('../../server/keyless-telemetry.js').then(
+    mod => mod.detectKeylessEnvDrift,
+  );
+
   if (newOrReadKeys) {
     await detectKeylessEnvDrift();
   }

packages/nextjs/src/server/keyless-telemetry.ts

@@ -1,9 +1,12 @@
 import type { TelemetryEventRaw } from '@clerk/types';
+import { promises as fs } from 'fs';
+import { join } from 'path';
 
 import { createClerkClientWithOptions } from './createClerkClient';
 
 const EVENT_KEYLESS_ENV_DRIFT_DETECTED = 'KEYLESS_ENV_DRIFT_DETECTED';
 const EVENT_SAMPLING_RATE = 1; // 100% sampling rate
+const TELEMETRY_FLAG_FILE = '.clerk/.tmp/telemetry.json';
 
 type EventKeylessEnvDriftPayload = {
   publicKeyMatch: boolean;
@@ -15,14 +18,61 @@ type EventKeylessEnvDriftPayload = {
 };
 
 /**
- * Detects environment variable drift for keyless Next.js applications and fires telemetry events.
+ * Gets the absolute path to the telemetry flag file.
  *
- * This function compares the publishableKey and secretKey values from `.clerk/.tmp/keyless.json`
- * with the `NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY` and `CLERK_SECRET_KEY` environment variables.
+ * This file is used to track whether telemetry events have already been fired
+ * to prevent duplicate event reporting during the application lifecycle.
  *
- * If there's a mismatch, it fires a `KEYLESS_ENV_DRIFT_DETECTED` event.
- * For local testing purposes, it also fires a `KEYLESS_ENV_DRIFT_NOT_DETECTED` event when
- * keys exist and match the environment variables.
+ * @returns The absolute path to the telemetry flag file in the project's .clerk/.tmp directory
+ */
+function getTelemetryFlagFilePath(): string {
+  return join(process.cwd(), TELEMETRY_FLAG_FILE);
+}
+
+/**
+ * Attempts to create a telemetry flag file to mark that a telemetry event has been fired.
+ *
+ * This function uses the 'wx' flag to create the file atomically - it will only succeed
+ * if the file doesn't already exist. This ensures that telemetry events are only fired
+ * once per application lifecycle, preventing duplicate event reporting.
+ *
+ * @returns Promise<boolean> - Returns true if the flag file was successfully created (meaning
+ *   the event should be fired), false if the file already exists (meaning the event was
+ *   already fired) or if there was an error creating the file
+ */
+async function tryMarkTelemetryEventAsFired(): Promise<boolean> {
+  try {
+    const flagData = {
+      firedAt: new Date().toISOString(),
+      event: EVENT_KEYLESS_ENV_DRIFT_DETECTED,
+    };
+    await fs.writeFile(getTelemetryFlagFilePath(), JSON.stringify(flagData, null, 2), { flag: 'wx' });
+    return true;
+  } catch (error: unknown) {
+    if ((error as { code?: string })?.code === 'EEXIST') {
+      return false;
+    }
+    console.warn('Failed to create telemetry flag file:', error);
+    return false;
+  }
+}
+
+/**
+ * Detects and reports environment drift between keyless configuration and environment variables.
+ *
+ * This function compares the Clerk keys stored in the keyless configuration file (.clerk/clerk.json)
+ * with the keys set in environment variables (NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY and CLERK_SECRET_KEY).
+ * If there's a mismatch (drift), it reports this as a telemetry event to help diagnose configuration issues.
+ *
+ * The function handles several scenarios:
+ * - Normal keyless mode: env vars missing but keyless file has keys (no drift)
+ * - Drift detected: env vars and keyless file have different keys
+ * - Mixed configuration: some keys match, others don't
+ *
+ * Telemetry events are only fired once per application lifecycle using a flag file mechanism
+ * to prevent duplicate reporting.
+ *
+ * @returns Promise<void> - Function completes silently, errors are logged but don't throw
  */
 export async function detectKeylessEnvDrift(): Promise<void> {
   // Only run on server side
@@ -79,14 +129,18 @@ export async function detectKeylessEnvDrift(): Promise<void> {
     });
 
     if (hasDrift) {
-      // Fire drift detected event
-      const driftDetectedEvent: TelemetryEventRaw<EventKeylessEnvDriftPayload> = {
-        event: EVENT_KEYLESS_ENV_DRIFT_DETECTED,
-        eventSamplingRate: EVENT_SAMPLING_RATE,
-        payload,
-      };
-
-      clerkClient.telemetry?.record(driftDetectedEvent);
+      const shouldFireEvent = await tryMarkTelemetryEventAsFired();
+
+      if (shouldFireEvent) {
+        // Fire drift detected event only if we successfully created the flag
+        const driftDetectedEvent: TelemetryEventRaw<EventKeylessEnvDriftPayload> = {
+          event: EVENT_KEYLESS_ENV_DRIFT_DETECTED,
+          eventSamplingRate: EVENT_SAMPLING_RATE,
+          payload,
+        };
+
+        clerkClient.telemetry?.record(driftDetectedEvent);
+      }
     }
   } catch (error) {
     // Silently handle errors to avoid breaking the application