Scheduled function sometimes throws error when using sendToTopic

Question

I've implemented a scheduled function in Firebase (1st generation) that runs every 5 minutes. The code snippet below is a simplified version of the function, which shows just the problematic part:

initializeApp()

export const example = runWith({
  timeoutSeconds: 20,
  memory: '128MB',
  maxInstances: 1,
  minInstances: 0,
})
  .region('europe-west1')
  .pubsub.schedule('*/5 * * * *')
  .onRun(async () => {
    const date = new Date();

    const weekday = date.getDay();
    const hour = date.getHours();
    const minute = Math.floor(date.getMinutes() / 15) * 15;

    const topicName = `${weekday}-${hour}-${minute}`;

    const messaging = getMessaging();

    try {
      await messaging.sendToTopic(
        topicName,
        {
          data: {
            mode: '15MinSchedule',
            type: topicName,
          },
        },
        {
          priority: 'high',
        },
      );
      debug(`Successfully sent to topic: ${topicName}`);
    } catch (err) {
      warn(`Error sending to topic ${topicName}:`, err);
    }
  });

The issue occurs intermittently, approximately every 2 to 3 hours, when the sendToTopic method throws the following error (the full log is provided at the end of this post):

"error":"Deprecated endpoint, see https://firebase.google.com/docs/cloud-messaging/migrate-v1"

Based on the error message, it appears that the function is attempting to access a deprecated FCM-endpoint (v1). I'm not sure, but I think the firebase-admin package should already be using the correct, non-deprecated endpoint without requiring any manual migration, right? However, most of the time everything works fine and as I said, it just throws the error around once every 2 hours, after which it sends the messages correctly again.

What I have already tried

• Deleted the build, package-lock.json and node_modules directory and redeployed the function
• Deleted schedule-function in google-cloud and redeployed the function

Package version:

"firebase-admin": "^12.3.1",
"firebase-functions": "^5.0.1",

Error log:

{
  "textPayload": "FirebaseMessagingError: An unknown server error was returned. Raw server response: \"{\"error\":\"Deprecated endpoint, see https://firebase.google.com/docs/cloud-messaging/migrate-v1\"}\"\n    at FirebaseMessagingError.fromServerError (/workspace/node_modules/firebase-admin/lib/utils/error.js:269:16)\n    at createFirebaseError (/workspace/node_modules/firebase-admin/lib/messaging/messaging-errors-internal.js:35:47)\n    at /workspace/node_modules/firebase-admin/lib/messaging/messaging-api-request-internal.js:80:75\n    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)\n    at async sendToTopic (/workspace/lib/scheduled/***.js:73:9)\n    at async Promise.all (index 1)\n    at async exports.default (/workspace/lib/scheduled/***.js:43:5)\n    at async /workspace/lib/group-functions/pubsub-group.js:56:5 {\n  errorInfo: {\n    code: 'messaging/unknown-error',\n    message: 'An unknown server error was returned. Raw server response: \"{\"error\":\"Deprecated endpoint, see https://firebase.google.com/docs/cloud-messaging/migrate-v1\"}\"'\n  },\n  codePrefix: 'messaging'\n}",
  "insertId": "66cdb534000ecdfcc85c9c9e",
  "resource": {
    "type": "cloud_function",
    "labels": {
      "function_name": "pubsub-min5Schedule",
      "region": "europe-west1",
      "project_id": "***"
    }
  },
  "timestamp": "2024-08-27T11:15:00.970236Z",
  "severity": "WARNING",
  "labels": {
    "runtime_version": "nodejs20_20240818_20_16_0_RC00",
    "execution_id": "***",
    "instance_id": "***"
  },
  "logName": "projects/***/logs/cloudfunctions.googleapis.com%2Fcloud-functions",
  "trace": "projects/***/traces/cee5cfbbaf474cae746709dafadd9785",
  "receiveTimestamp": "2024-08-27T11:15:00.995052585Z"
}

Answer 1

I found the solution by myself:

As of August 22, 2024, the sendToTopic and sendToCondition methods have been deprecated, and we now need to use send for both. I've run this for a day, and everything is working smoothly without any issues.