rend.py

import logging
import os
import sys
import time

import requests

DEFAULT_PING_INTERVAL = 240
MAX_FAILURES = 2


logging.basicConfig(
    level=logging.INFO, format="%(asctime)s - %(levelname)s - %(message)s"
)
logger = logging.getLogger()
handler = logging.StreamHandler()
handler.setLevel(logging.INFO)
logger.addHandler(handler)


def get_app_url():
    """
    Retrieves the app URL from the environment variable 'APP_URL' or
    the first command-line argument. If neither is provided, returns None.
    """
    app_url = os.getenv("APP_URL") or (sys.argv[1] if len(sys.argv) > 1 else None)
    return app_url


def get_ping_interval():
    """
    Returns the ping interval in seconds from the 'PING_INTERVAL' environment variable.
    Falls back to DEFAULT_PING_INTERVAL if the environment variable is not set or invalid.
    """
    try:
        return int(os.getenv("PING_INTERVAL", DEFAULT_PING_INTERVAL))
    except ValueError:
        logging.warning("Invalid PING_INTERVAL value; using default.")
        return DEFAULT_PING_INTERVAL


def get_delay():
    """
    Returns the delay in seconds from the 'DELAY' environment variable.
    Defaults to 300 seconds if not set or if the value is invalid.
    """
    try:
        return int(os.getenv("DELAY", 300))
    except ValueError:
        logging.warning("Invalid DELAY value; using default 300 seconds.")
        return 300


def should_delay_ping():
    """
    Determines whether to delay before starting to ping based on the 'DELAY_PING'
    environment variable. Accepts values like 'True', '1', or 'yes' (case insensitive)
    as True.
    """
    return os.getenv("DELAY_PING", "False").lower() in ("true", "1", "yes")


def ping_url(session, url):
    """
    Attempts to ping the specified URL using the provided session.
    Returns True if the HTTP response status code is 200; otherwise, returns False.
    """
    try:
        response = session.get(url, timeout=10)
        if response.status_code == 200:
            logging.info(f"Ping successful: {response.status_code} - {url}")
            logger.handlers[0].flush()
            return True
        else:
            logging.warning(f"Ping failed with status: {response.status_code} - {url}")
            logger.handlers[0].flush()
            return False
    except requests.RequestException as e:
        logging.error(f"Error pinging URL: {e}")
        logger.handlers[0].flush()
        return False


def main():
    app_url = get_app_url()
    if not app_url:
        logging.error(
            "No app URL provided. Set the 'APP_URL' environment variable or pass the URL as a command-line argument."
        )
        logger.handlers[0].flush()
        sys.exit(1)

    ping_interval = get_ping_interval()
    logging.info(f"Starting to ping {app_url} every {ping_interval / 60} minutes...")
    logger.handlers[0].flush()

    if should_delay_ping():
        delay_seconds = get_delay()
        logging.info(
            f"Delaying start of pinging by {delay_seconds} seconds as per DELAY_PING setting."
        )
        logger.handlers[0].flush()
        time.sleep(delay_seconds)

    failure_count = 0

    with requests.Session() as session:
        try:
            while True:
                success = ping_url(session, app_url)
                if success:
                    failure_count = 0
                else:
                    failure_count += 1
                    if failure_count >= MAX_FAILURES:
                        logging.error(
                            f"Maximum failure count reached ({MAX_FAILURES}). Stopping ping function."
                        )
                        logger.handlers[0].flush()
                        break
                time.sleep(ping_interval)
        except KeyboardInterrupt:
            logging.info("Ping process interrupted by user.")
            logger.handlers[0].flush()


if __name__ == "__main__":
    main()