Collect unsubscribes and bounces for your list

from google.oauth2.credentials import Credentials
from googleapiclient.discovery import build
import re
from datetime import datetime
from zoneinfo import ZoneInfo
from clickruntime import on_trigger, credentials, state, notify

QUERY = 'newer_than:1d (subject:unsubscribe OR from:mailer-daemon OR subject:"delivery status notification")'
EMAIL = re.compile(r"[\w.+-]+@[\w-]+\.[\w.]+")

@on_trigger
def run(event):
    gmail = build("gmail", "v1", credentials=Credentials(credentials.connection("google", "work")), cache_discovery=False)
    labels = {l["name"]: l["id"] for l in gmail.users().labels().list(userId="me").execute()["labels"]}
    label = labels.get("Unsub-Bounce") or gmail.users().labels().create(userId="me", body={"name": "Unsub-Bounce"}).execute()["id"]
    pending = set(state.get("pending") or [])
    msgs = gmail.users().messages().list(userId="me", q=QUERY + " -label:Unsub-Bounce").execute().get("messages", [])
    for m in msgs:
        msg = gmail.users().messages().get(userId="me", id=m["id"], format="metadata", metadataHeaders=["From"]).execute()
        sender = next(h["value"] for h in msg["payload"]["headers"] if h["name"] == "From")
        source = msg["snippet"] if "mailer-daemon" in sender.lower() else sender
        pending.update(a.lower() for a in EMAIL.findall(source) if "mailer-daemon" not in a.lower())
        gmail.users().messages().modify(userId="me", id=m["id"], body={"addLabelIds": [label]}).execute()
    if datetime.now(ZoneInfo("Europe/London")).hour == 17 and pending:  # once a day
        notify.email_me(f"{len(pending)} unsubscribes and bounces", "\n".join(sorted(pending)))
        pending = set()
    state.set("pending", sorted(pending))
    return {"labelled": len(msgs)}