Get an email when your website traffic changes sharply

import base64
from google.oauth2.credentials import Credentials
from googleapiclient.discovery import build
from datetime import date, timedelta
from clickruntime import on_trigger, http, credentials, ai

def api(name, version):
    return build(name, version, credentials=Credentials(credentials.connection("google", "work")), cache_discovery=False)

def send_gmail(to, subject, text):
    raw = base64.urlsafe_b64encode(f"To: {to}\r\nSubject: {subject}\r\nContent-Type: text/plain; charset=utf-8\r\n\r\n{text}".encode()).decode()
    api("gmail", "v1").users().messages().send(userId="me", body={"raw": raw}).execute()

PROPERTY = "123456789"

def ga(body):
    url = f"https://analyticsdata.googleapis.com/v1beta/properties/{PROPERTY}:runReport"
    return http.post(url, headers={"Authorization": f"Bearer {credentials.connection('google', 'work')}"}, json=body).json().get("rows", [])

@on_trigger
def run(event):
    ranges = [{"startDate": (d := (date.today() - timedelta(days=n)).isoformat()), "endDate": d} for n in (1, 8, 15, 22)]
    rows = ga({"dateRanges": ranges, "dimensions": [{"name": "sessionSource"}], "metrics": [{"name": "sessions"}, {"name": "conversions"}]})
    data, changes = {}, []
    for r in rows:
        src, rng = r["dimensionValues"][0]["value"], int(r["dimensionValues"][1]["value"].split("_")[-1])
        data.setdefault(src, [0] * 4)[rng] = float(r["metricValues"][0]["value"])
    for src, v in data.items():
        if (avg := sum(v[1:]) / 3) >= 20 and abs(v[0] - avg) / avg > 0.3:
            changes.append(f"{src}: {v[0]:.0f} sessions yesterday vs {avg:.0f} usual ({(v[0] - avg) / avg * 100:+.0f}%)")
    if not changes:
        return {"alerts": 0}
    note = ai.generate("\n".join(changes), system="Explain these website traffic changes in plain words: the likely cause and one suggested action each.", max_output_tokens=400).text
    send_gmail("you@example.com", f"Traffic alert: {len(changes)} unusual changes", f"{note}\n\n" + "\n".join(changes))
    return {"alerts": len(changes)}