alarmmonitor.py

import logging
import time
from sched import scheduler

from chromiumbrowsercontroller import ChromiumBrowserController


class AlarmMonitor:
    """Controls the application's execution flow."""

    def __init__(self, polling_interval, send_errors, send_starts, blaulichtsms_controller,
                 hdmi_cec_controller, browser_controller, mail_sender):
        self.logger = logging.getLogger(__name__)
        self.scheduler = scheduler(time.time, time.sleep)
        self.blaulichtsms_controller = blaulichtsms_controller
        self.hdmi_cec_controller = hdmi_cec_controller
        self.browser_controller = browser_controller
        self.mail_sender = mail_sender
        self.browser_controller.start()

        self._polling_interval = polling_interval
        self._send_errors = send_errors
        self._send_starts = send_starts

        self._is_browser_error = False

    def _run_helper(self):
        """The main loop of the application.
        Reschedules itself to run every :_polling_interval: seconds.

        Ensures that a browser which is displaying the blaulichtSMS Einsatzmonitor dashboard is running.
        Checks if communication with an HDMI device via CEC is possible.
        """
        self.logger.debug("running helper")
        self.scheduler.enter(self._polling_interval, 1, self._run_helper)

        self._check_browser_status()
        if self.blaulichtsms_controller.is_alarm():
            self.hdmi_cec_controller.activate_source()
        else:
            self.hdmi_cec_controller.standby()

    def _check_browser_status(self):
        """Checks if the browser process which is displaying the blaulichtSMS
        Einsatzmonitor dashboard is still running.

        If the process is no longer running, it starts a new one.
        """
        if not self.browser_controller.is_alive():
            self.logger.warning("The browser is not running. Starting it.")

            if self._send_errors and not self._is_browser_error:
                self.mail_sender.send_message("The browser of the AlarmMonitor has crashed.\n"
                                              "A mail is sent as soon as the problem is resolved.")
                self._is_browser_error = True

            session_id = self.blaulichtsms_controller.get_session()
            self.browser_controller = ChromiumBrowserController(session_id)
            self.browser_controller.start()
        elif self._is_browser_error:
            self.mail_sender.send_message("The browser issue of the AlarmMonitor is resolved.")
            self._is_browser_error = False

    def run(self):
        self.logger.info("START - Started alarm monitor")
        if self._send_starts:
            self.mail_sender.send_message("The AlarmMonitor has started.")
        try:
            self._run_helper()
            self.scheduler.run()
        except KeyboardInterrupt:
            self.logger.info("Stopping alarm monitor")
        finally:
            if self.hdmi_cec_controller.is_on():
                self.hdmi_cec_controller.standby()
            self.browser_controller.terminate()