Mobile proxies for reselling

import csv
from datetime import date, datetime

import requests

RENTALS_FILE = "rentals.csv"
REPORT_FILE = "rentals_report.csv"
IP_ECHO = "https://api.ipify.org"
REMIND_DAYS = 3


def is_alive(proxy):
    try:
        response = requests.get(IP_ECHO, proxies={"http": proxy, "https": proxy}, timeout=15)
        response.raise_for_status()
        return True
    except requests.RequestException:
        return False


def main():
    with open(RENTALS_FILE, newline="") as f:
        rentals = list(csv.DictReader(f))

    today = date.today()
    revenue, reminders, outages = 0.0, [], []
    with open(REPORT_FILE, "w", newline="") as f:
        writer = csv.writer(f)
        writer.writerow(["customer", "paid_until", "days_left", "proxy_state"])
        for rental in rentals:
            paid_until = datetime.strptime(rental["paid_until"], "%Y-%m-%d").date()
            days_left = (paid_until - today).days
            active = days_left >= 0
            state = "expired"
            if active:
                revenue += float(rental["price"])
                state = "up" if is_alive(rental["proxy"]) else "DOWN"
                if state == "DOWN":
                    outages.append(rental["customer"])
                if days_left <= REMIND_DAYS:
                    reminders.append(f"{rental['customer']} ({days_left} d)")
            writer.writerow([rental["customer"], rental["paid_until"], days_left, state])

    print(f"active rentals bring in {revenue:.2f} per month")
    print(f"remind about renewal: {', '.join(reminders) or 'nobody'}")
    print(f"paying customers with a dead proxy: {', '.join(outages) or 'none'}")
    raise SystemExit(1 if outages else 0)


if __name__ == "__main__":
    main()