Scanner get its own thread, one instance might be used for several files

bin/supysonic-watcher

@@ -21,6 +21,7 @@
 
 import time, sys
 import logging
+from threading import Thread, Lock
 from logging.handlers import TimedRotatingFileHandler
 from watchdog.observers import Observer
 from watchdog.events import PatternMatchingEventHandler
@@ -29,36 +30,83 @@ from supysonic import config
 from supysonic.scanner import Scanner
 
 class SupysonicWatcherEventHandler(PatternMatchingEventHandler):
-	def __init__(self, logger):
+	def __init__(self, queue, logger):
 		extensions = config.get('base', 'scanner_extensions')
 		patterns = map(lambda e: "*." + e.lower(), extensions.split()) if extensions else None
 		super(SupysonicWatcherEventHandler, self).__init__(patterns = patterns, ignore_directories = True)
 
+		self.__queue = queue
 		self.__logger = logger
 
 	def on_created(self, event):
-		self.__logger.debug("Scanning created file %s", event.src_path)
-		Scanner(db.session).scan_file(event.src_path)
-		db.session.commit()
+		self.__logger.debug("File created: '%s'", event.src_path)
+		self.__queue.put(event.src_path)
 
 	def on_deleted(self, event):
-		self.__logger.debug("File %s deleted", event.src_path)
+		self.__logger.debug("File deleted: '%s'", event.src_path)
 		track = db.Track.query.filter(db.Track.path == event.src_path).first()
 		if track:
 			folder = track.root_folder
 			Scanner(db.session).prune(folder)
 			db.session.commit()
+			db.session.remove()
 		else:
 			self.__logger.debug("Deleted file %s not in the database", event.src_path)
 
 	def on_modified(self, event):
-		self.__logger.debug("Scanning modified file %s", event.src_path)
-		Scanner(db.session).scan_file(event.src_path)
-		db.session.commit()
+		self.__logger.debug("File modified: '%s'", event.src_path)
+		self.__queue.put(event.src_path)
 
 	def on_moved(self, event):
 		pass
 
+class ScannerProcessingQueue(Thread):
+	def __init__(self, logger):
+		super(ScannerProcessingQueue, self).__init__()
+
+		self.__logger = logger
+		self.__lock = Lock()
+		self.__queue = {}
+		self.__running = True
+
+	def run(self):
+		while self.__running:
+			time.sleep(5)
+
+			with self.__lock:
+				if not self.__queue:
+					continue
+
+			self.__logger.debug("Instantiating scanner")
+			scanner = Scanner(db.session)
+
+			self.__lock.acquire()
+			while self.__queue:
+				path = sorted(self.__queue.iteritems(), key = lambda i: i[1])[0][0]
+				self.__lock.release()
+
+				self.__logger.info("Scanning: '%s'", path)
+				scanner.scan_file(path)
+
+				self.__lock.acquire()
+				del self.__queue[path]
+			self.__lock.release()
+
+			db.session.commit()
+			db.session.remove()
+			self.__logger.debug("Freeing scanner")
+			del scanner
+
+	def stop(self):
+		self.__running = False
+
+	def put(self, path):
+		if not self.__running:
+			raise RuntimeError("Trying to put an item in a stopped queue")
+
+		with self.__lock:
+			self.__queue[path] = time.time()
+
 if __name__ == "__main__":
 	if not config.check():
 		sys.exit(1)
@@ -87,12 +135,15 @@ if __name__ == "__main__":
 		logger.info("No folder set. Exiting.")
 		sys.exit(0)
 
-	handler = SupysonicWatcherEventHandler(logger)
+	queue = ScannerProcessingQueue(logger)
+	handler = SupysonicWatcherEventHandler(queue, logger)
 	observer = Observer()
+
 	for folder in db.Folder.query.filter(db.Folder.root == True):
 		logger.info("Starting watcher for %s", folder.path)
 		observer.schedule(handler, folder.path, recursive = True)
 
+	queue.start()
 	observer.start()
 	try:
 		while True:
@@ -101,4 +152,6 @@ if __name__ == "__main__":
 		logger.info("Stopping watcher")
 		observer.stop()
 	observer.join()
+	queue.stop()
+	queue.join()