I deployed the following Python Firebase cloud function that’s supposed to be triggered on change to document from Collection Appointments, then send an FCM accordingly to associated user.

# The Cloud Functions for Firebase SDK to create Cloud Functions and set up triggers.
from firebase_functions import firestore_fn, https_fn

# The Firebase Admin SDK to access Cloud Firestore.
from firebase_admin import initialize_app, firestore, messaging
import google.cloud.firestore


app = initialize_app()

db = firestore.client

@firestore_fn.on_document_updated(document="Appointments/{appointmentId}")
def send_appointment_notification(event: firestore_fn.Event[firestore_fn.DocumentSnapshot | None]):
    # Get the updated data after the update operation
    updated_data = event.after.data()

    # Access the status field from the updated data
    status = updated_data.get("status")

    if status in ['Approved', 'Declined']:
        # Get the clientId from the appointment document
        client_id = updated_data.get("clientId")

        # Retrieve user document to get the fcmtoken
        user_ref = db.collection('Users').document(client_id)
        user_doc = user_ref.get()

        if user_doc.exists:
            user_data = user_doc.to_dict()
            if 'fcmToken' in user_data:
                fcmtoken = user_data['fcmToken']

                # Compose notification message
                if status == 'Approved':
                    notification_title = f'Appointment Approved'
                elif status == 'Declined':
                    notification_title = f'Appointment Declined'

                message = messaging.Message(
                    data={
                        'appointmentId': updated_data.get("appointmentId")
                    },
                    notification={
                        'title': notification_title,
                        'body': f'Appointment on {updated_data.get("startDateTime")} has been {status.lower()}'
                    },
                    token=fcmtoken
                )

                # Send the notification
                response = messaging.send(message)
                print('Notification sent successfully:', response)
            else:
                print('No fcmtoken found for the user.')
        else:
            print(f'User document with ID {client_id} does not exist.')

    else:
        print(f'Status {status} is not Approved or Declined.')

I get the following error in my logs when it’s triggered

Traceback (most recent call last):
File “/layers/google.python.pip/pip/lib/python3.12/site-packages/flask/app.py”, line 1473, in wsgi_app
response = self.full_dispatch_request()
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File “/layers/google.python.pip/pip/lib/python3.12/site-packages/flask/app.py”, line 882, in full_dispatch_request
rv = self.handle_user_exception(e)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File “/layers/google.python.pip/pip/lib/python3.12/site-packages/flask/app.py”, line 880, in full_dispatch_request
rv = self.dispatch_request()
^^^^^^^^^^^^^^^^^^^^^^^
File “/layers/google.python.pip/pip/lib/python3.12/site-packages/flask/app.py”, line 865, in dispatch_request
return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args) # type: ignore[no-any-return]
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File “/layers/google.python.pip/pip/lib/python3.12/site-packages/functions_framework/execution_id.py”, line 106, in wrapper
return view_function(*args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File “/layers/google.python.pip/pip/lib/python3.12/site-packages/functions_framework/init.py”, line 188, in view_func
function(event)
File “/layers/google.python.pip/pip/lib/python3.12/site-packages/firebase_functions/firestore_fn.py”, line 255, in on_document_updated_wrapped
return _firestore_endpoint_handler(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File “/layers/google.python.pip/pip/lib/python3.12/site-packages/firebase_functions/firestore_fn.py”, line 176, in _firestore_endpoint_handler
func(database_event)
File “/workspace/main.py”, line 35, in send_appointment_notification
updated_data = event.after.data()
^^^^^^^^^^^
AttributeError: ‘Event’ object has no attribute ‘after’

previously I would use even.data.get(“status”) and I would get

status = event.data.get("status") ^^^^^^^^^^^^^^ AttributeError: 'Change' object has no attribute 'get'