Refactor watchdog Observer handling to a mixin

lib/tfw/components/directory_monitor.py

@@ -3,31 +3,24 @@
 
 from functools import wraps
 
-from watchdog.observers import Observer
 from watchdog.events import FileSystemEventHandler as FileSystemWatchdogEventHandler
 
 from tfw.networking.event_handlers import ServerUplinkConnector
 from tfw.components.decorators import RateLimiter
+from tfw.components.mixins import ObserverMixin
 
 from tfw.config.logs import logging
 
 LOG = logging.getLogger(__name__)
 
 
-class DirectoryMonitor:
+class DirectoryMonitor(ObserverMixin):
     def __init__(self, directory):
-        self.observer = Observer()
+        ObserverMixin.__init__(self)
         self.eventhandler = WebideReloadWatchdogEventHandler()
         self.observer.schedule(self.eventhandler, directory, recursive=True)
         self.pause, self.resume = self.eventhandler.pause, self.eventhandler.resume
 
-    def watch(self):
-        self.observer.start()
-
-    def stop(self):
-        self.observer.stop()
-        self.observer.join()
-
     @property
     def ignore(self):
         return self.eventhandler.ignore

lib/tfw/components/history_monitor.py

@@ -6,10 +6,9 @@ from re import findall
 from re import compile as compileregex
 from abc import ABC, abstractmethod
 
-from watchdog.observers import Observer
 from watchdog.events import PatternMatchingEventHandler
 
-from tfw.components.mixins import CallbackMixin
+from tfw.components.mixins import CallbackMixin, ObserverMixin
 from tfw.components.decorators import RateLimiter
 
 
@@ -24,13 +23,13 @@ class CallbackEventHandler(PatternMatchingEventHandler, ABC):
             callback()
 
 
-class HistoryMonitor(CallbackMixin, ABC):
+class HistoryMonitor(CallbackMixin, ObserverMixin, ABC):
     def __init__(self, histfile):
         CallbackMixin.__init__(self)
+        ObserverMixin.__init__(self)
         self.histfile = histfile
         self._history = []
         self._last_length = len(self._history)
-        self.observer = Observer()
         self.observer.schedule(CallbackEventHandler([self.histfile],
                                                     self._fetch_history,
                                                     self._invoke_callbacks),
@@ -60,13 +59,6 @@ class HistoryMonitor(CallbackMixin, ABC):
         if self._last_length < len(self._history):
             self._execute_callbacks(self.history)
 
-    def watch(self):
-        self.observer.start()
-
-    def stop(self):
-        self.observer.stop()
-        self.observer.join()
-
 
 class BashMonitor(HistoryMonitor):
     @property

lib/tfw/components/mixins/__init__.py

@@ -3,3 +3,4 @@
 
 from .supervisor_mixin import SupervisorMixin
 from .callback_mixin import CallbackMixin
+from .observer_mixin import ObserverMixin

lib/tfw/components/mixins/observer_mixin.py

@@ -0,0 +1,16 @@
+# Copyright (C) 2018 Avatao.com Innovative Learning Kft.
+# All Rights Reserved. See LICENSE file for details.
+
+from watchdog.observers import Observer
+
+
+class ObserverMixin:
+    def __init__(self):
+        self.observer = Observer()
+
+    def watch(self):
+        self.observer.start()
+
+    def stop(self):
+        self.observer.stop()
+        self.observer.join()