# Here is a sample from https://cloud.google.com/functions/docs/calling/cloud-firestore#functions_firebase_firestore-python
import json
def hello_firestore(data, context):
""" Triggered by a change to a Firestore document.
Args:
data (dict): The event payload.
context (google.cloud.functions.Context): Metadata for the event.
"""
trigger_resource = context.resource
print('Function triggered by change to: %s' % trigger_resource)
print('
Old value:')
print(json.dumps(data["oldValue"]))
print('
New value:')
print(json.dumps(data["value"]))