EDMarketConnector/dashboard.py

import json
from calendar import timegm
from os.path import isdir, isfile, join, getsize
from sys import platform
import time

from config import config
from EDMCLogging import get_main_logger

logger = get_main_logger()

if platform=='darwin':
    from watchdog.observers import Observer
    from watchdog.events import FileSystemEventHandler

elif platform=='win32':
    from watchdog.observers import Observer
    from watchdog.events import FileSystemEventHandler

else:
    # Linux's inotify doesn't work over CIFS or NFS, so poll
    FileSystemEventHandler = object	# dummy


# Status.json handler
class Dashboard(FileSystemEventHandler):

    _POLL = 1  # Fallback polling interval

    def __init__(self):
        FileSystemEventHandler.__init__(self)	# futureproofing - not need for current version of watchdog
        self.root = None
        self.currentdir = None		# The actual logdir that we're monitoring
        self.observer = None
        self.observed = None		# a watchdog ObservedWatch, or None if polling
        self.status = {}		# Current status for communicating status back to main thread

    def start(self, root, started):
        """Start monitoring of Journal directory."""
        logger.debug('Starting...')
        self.root = root
        self.session_start = started

        logdir = config.get_str('journaldir', default=str(config.default_journal_dir))
        if logdir == '':
            logdir = str(config.default_journal_dir)
        
        if not logdir or not isdir(logdir):
            logger.info(f"No logdir, or it isn't a directory: {logdir=}")
            self.stop()
            return False

        if self.currentdir and self.currentdir != logdir:
            logger.debug(f"{self.currentdir=} != {logdir=}")
            self.stop()

        self.currentdir = logdir

        # Set up a watchdog observer.
        # File system events are unreliable/non-existent over network drives on Linux.
        # We can't easily tell whether a path points to a network drive, so assume
        # any non-standard logdir might be on a network drive and poll instead.
        polling = platform != 'win32'
        if not polling and not self.observer:
            logger.debug('Setting up observer...')
            self.observer = Observer()
            self.observer.daemon = True
            self.observer.start()
            logger.debug('Done')

        elif polling and self.observer:
            logger.debug('Using polling, stopping observer...')
            self.observer.stop()
            self.observer = None
            logger.debug('Done')

        if not self.observed and not polling:
            logger.debug('Starting observer...')
            self.observed = self.observer.schedule(self, self.currentdir)
            logger.debug('Done')

        logger.info(f'{polling and "Polling" or "Monitoring"} Dashboard "{self.currentdir}"')

        # Even if we're not intending to poll, poll at least once to process pre-existing
        # data and to check whether the watchdog thread has crashed due to events not
        # being supported on this filesystem.
        logger.debug('Polling once to process pre-existing data, and check whether watchdog thread crashed...')
        self.root.after(int(self._POLL * 1000/2), self.poll, True)
        logger.debug('Done.')

        return True

    def stop(self):
        """Stop monitoring dashboard."""
        logger.debug('Stopping monitoring Dashboard')
        self.currentdir = None

        if self.observed:
            logger.debug('Was observed')
            self.observed = None
            logger.debug('Unscheduling all observer')
            self.observer.unschedule_all()
            logger.debug('Done.')

        self.status = {}
        logger.debug('Done.')

    def close(self):
        """Close down dashboard."""
        logger.debug('Calling self.stop()')
        self.stop()

        if self.observer:
            logger.debug('Calling self.observer.stop()')
            self.observer.stop()
            logger.debug('Done')

        if self.observer:
            logger.debug('Joining self.observer...')
            self.observer.join()
            logger.debug('Done')
            self.observer = None

        logger.debug('Done.')

    def poll(self, first_time=False):
        if not self.currentdir:
            # Stopped
            self.status = {}
        else:
            self.process()

            if first_time:
                # Watchdog thread
                emitter = self.observed and self.observer._emitter_for_watch[self.observed]	# Note: Uses undocumented attribute
                if emitter and emitter.is_alive():
                    return	# Watchdog thread still running - stop polling

            self.root.after(self._POLL * 1000, self.poll)	# keep polling

    def on_modified(self, event):
        # watchdog callback - DirModifiedEvent on macOS, FileModifiedEvent on Windows
        if event.is_directory or (isfile(event.src_path) and getsize(event.src_path)):	# Can get on_modified events when the file is emptied
            self.process(event.src_path if not event.is_directory else None)

    # Can be called either in watchdog thread or, if polling, in main thread.
    def process(self, logfile=None):
        if config.shutting_down:
            return

        try:
            with open(join(self.currentdir, 'Status.json'), 'rb') as h:
                data = h.read().strip()

                if data:  # Can be empty if polling while the file is being re-written
                    entry = json.loads(data)

                    # Status file is shared between beta and live. So filter out status not in this game session.
                    if (
                            timegm(time.strptime(entry['timestamp'], '%Y-%m-%dT%H:%M:%SZ')) >= self.session_start
                            and self.status != entry
                    ):
                        self.status = entry
                        self.root.event_generate('<<DashboardEvent>>', when="tail")

        except Exception:
            logger.exception('Processing Status.json')

# singleton
dashboard = Dashboard()