Google Cloud Function to filter "Open To Internet" firewall rules

main.py

import base64
import json
import requests

def filter_rule(event, context):
    """Triggered from a message on a Cloud Pub/Sub topic.
    Args:
         event (dict): Event payload.
         context (google.cloud.functions.Context): Metadata for the event.
    """
    URL = "https://hooks.slack.com/services/T00000000/B00000000/XXXXXXXXXXXXXXXXXXXXXXXX"
    HEADERS = {"content-type":"application/json"}
    pubsub_message = base64.b64decode(event['data']).decode('utf-8')
    parsed = json.loads(pubsub_message)
    print(parsed)
    data = get_data(parsed)
    source_ranges = data["sourceRanges"]
    if '0.0.0.0/0' in source_ranges:
        print('Found an open to internet rule')
        name = data["name"]
        network = data["network"]
        creation_time = data["creationTimestamp"]
        message = f"An open to internet firewall rule *{name}* created in network {network} at *{creation_time}*."
        salck_payload = json.dumps({"text" : message})
        r = requests.post(URL, data=salck_payload, headers=HEADERS)
        print(r.status_code, r.reason)


def get_data(parsed):
    try:
        return parsed["asset"]["resource"]["data"]
    except:
        return parsed["priorAsset"]["resource"]["data"]