Implement proof of concept directory event monitoring

lib/tfw/components/directory_monitor.py

@@ -0,0 +1,26 @@
+from watchdog.observers import Observer
+from watchdog.events import FileSystemEventHandler
+
+from tfw.message_sender import MessageSender
+
+
+class MessagingEventHandler(FileSystemEventHandler):
+    def __init__(self):
+        super().__init__()
+        self.message_sender = MessageSender()
+
+    def on_modified(self, event):
+        self.message_sender.send('Watchdog', 'CECA')
+
+
+class DirectoryMonitor:
+    def __init__(self, directory):
+        self.observer = Observer()
+        self.observer.schedule(MessagingEventHandler(), directory, recursive=True)
+
+    def watch(self):
+        self.observer.start()
+
+    def stop(self):
+        self.observer.stop()
+        self.observer.join()

lib/tfw/components/source_code_event_handler.py

@@ -3,6 +3,7 @@ from glob import glob
 
 from tfw.util import SupervisorMixin
 from tfw.event_handler_base import EventHandlerBase
+from tfw.components.directory_monitor import DirectoryMonitor
 
 from tfw.config.logs import logging
 log = logging.getLogger(__name__)
@@ -56,6 +57,9 @@ class SourceCodeEventHandler(EventHandlerBase, SupervisorMixin):
             'select': self.select
         }
 
+        self.monitor = DirectoryMonitor(directory)
+        self.monitor.watch()    # This runs on a separate thread TODO: when to call stop()?
+
     def read(self, data):
         try: data['content'] = self.filemanager.file_contents
         except PermissionError: data['content'] = 'You have no permission to open that file :('

requirements.txt

@@ -2,3 +2,4 @@ tornado==4.5.3
 pyzmq==16.0.4
 transitions==0.6.4
 terminado==0.8.1
+watchdog==0.8.3