baseimage-tutorial-framework/lib/tfw/components/directory_monitor.py

# Copyright (C) 2018 Avatao.com Innovative Learning Kft.
# All Rights Reserved. See LICENSE file for details.

import logging
from functools import wraps

from watchdog.events import FileSystemEventHandler as FileSystemWatchdogEventHandler

from tfw.networking import Scope
from tfw.event_handlers import TFWServerUplinkConnector
from tfw.decorators.rate_limiter import RateLimiter
from tfw.mixins.observer_mixin import ObserverMixin

LOG = logging.getLogger(__name__)


class DirectoryMonitor(ObserverMixin):
    def __init__(self, ide_key, directories):
        self.eventhandler = IdeReloadWatchdogEventHandler(ide_key)
        for directory in directories:
            self.observer.schedule(self.eventhandler, directory, recursive=True)

        self.pause, self.resume = self.eventhandler.pause, self.eventhandler.resume

    @property
    def ignore(self):
        return self.eventhandler.ignore

    @ignore.setter
    def ignore(self, value):
        self.eventhandler.ignore = value if value >= 0 else 0

    @property
    def pauser(self):
        return DirectoryMonitor.Pauser(self)

    class Pauser:
        def __init__(self, directory_monitor):
            self.directorymonitor = directory_monitor
        def __enter__(self):
            self.directorymonitor.pause()
        def __exit__(self, exc_type, exc_val, exc_tb):
            self.directorymonitor.resume()


class IdeReloadWatchdogEventHandler(FileSystemWatchdogEventHandler):
    def __init__(self, ide_key):
        super().__init__()
        self.ide_key = ide_key
        self.uplink = TFWServerUplinkConnector()
        self._paused = False
        self.ignore = 0

    def pause(self):
        self._paused = True

    def resume(self):
        self._paused = False

    @RateLimiter(rate_per_second=2)
    def on_modified(self, event):
        if self._paused:
            return
        if self.ignore > 0:
            self.ignore = self.ignore - 1
            return
        LOG.debug(event)
        self.uplink.send_message({
            'key': self.ide_key,
            'data': {'command': 'reload'}
        }, Scope.WEBSOCKET)


def with_monitor_paused(fun):
    @wraps(fun)
    def wrapper(self, *args, **kwargs):
        if self.monitor:
            with self.monitor.pauser:
                return fun(self, *args, **kwargs)
        return fun(self, *args, **kwargs)
    return wrapper