albs-oval-errata-diff/albs_oval_errata_diff/start.py

"""
service compares rhel oval with alma ovals and errata ovals
results available via API Call
"""
import copy
import logging
from logging.handlers import RotatingFileHandler
import threading
from time import sleep
from ipaddress import IPv4Address
import json

from aiohttp import web

from .config import get_config, Config
from .comparer import comparer_run


# This dict holds all current differences
diffs = {}
diffs_lock = threading.Lock()


async def web_handler(_):
    """
    web_handler returns diffs as JSON file
    """
    data = {}
    try:
        diffs_lock.acquire()
        data = copy.deepcopy(diffs)
        diffs_lock.release()
    except Exception as err:  # pylint: disable=broad-except
        logging.critical("Unhandled exeption %s", err, exc_info=True)
    return web.json_response(data=data)


def webserver_run(server_ip: IPv4Address, server_port: str):
    """
    webserver_run starts webserver component
    """
    app = web.Application()
    app.add_routes([web.get('/', web_handler)])
    web.run_app(app=app, host=str(server_ip), port=server_port)


def diff_checker(config: Config):
    """
    Runs comparer component in infinite loop
    """
    while True:
        logging.info("Start comparing")
        # generating new diff
        try:
            result = comparer_run(config)
        except Exception as err:  # pylint: disable=broad-except
            logging.critical("Unhandled exeption %s", err, exc_info=True)
        else:
            logging.info("Finished comparing, updating diff dict")
            diffs_lock.acquire()
            global diffs  # pylint: disable=invalid-name,global-statement
            diffs = result
            diffs_lock.release()

            # dumping
            logging.info("Saving results to disk")
            try:
                with open(config.diff_file, 'w', encoding='utf-8') as flw:
                    json.dump(result, flw, indent=4)
            except Exception as err:  # pylint: disable=broad-except
                logging.critical("Unhandled exeption %s", err, exc_info=True)
        logging.info("Done")

        logging.info("Finished comparing, go to sleep for %d minutes",
                     config.update_interval_minutes)
        sleep(config.update_interval_minutes * 60)


def start(yaml_path: str):
    """
    start starts comparer and webserver components
    each component runs in it`s own thread
    """
    config = get_config(yaml_path)

    # making sure that parent directories exist
    for path in [config.log_file, config.log_file]:
        if not path.parent.exists():
            path.parent.mkdir()

    # configuring logging
    logging.basicConfig(level=logging.INFO,
                        format='%(asctime)s %(levelname)s %(funcName)s %(message)s',
                        handlers=[RotatingFileHandler(config.log_file, maxBytes=10000000, backupCount=3)])

    logging.info("Trying to load diff file from disk")
    try:
        with open(config.diff_file, 'r', encoding='utf-8') as flr:
            loaded_data = json.load(flr)
        diffs_lock.acquire()
        global diffs  # pylint: disable=invalid-name,global-statement
        diffs = loaded_data
        diffs_lock.release()
    except Exception as err:  # pylint: disable=broad-except
        logging.warning('Cant load data from disk %s', err)
    else:
        logging.info('Diff file was loaded')

    logging.info("Starting diff_checker in background")
    thread = threading.Thread(target=diff_checker, args=(config,))
    thread.daemon = True
    thread.start()
    logging.info("Starting webserver")
    webserver_run(config.server_ip, config.server_port)