373 lines
12 KiB
Python
373 lines
12 KiB
Python
# coding: utf-8
|
|
#
|
|
# Copyright 2011 Yesudeep Mangalapilly <yesudeep@gmail.com>
|
|
# Copyright 2012 Google, Inc & contributors.
|
|
#
|
|
# Licensed under the Apache License, Version 2.0 (the "License");
|
|
# you may not use this file except in compliance with the License.
|
|
# You may obtain a copy of the License at
|
|
#
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
#
|
|
# Unless required by applicable law or agreed to in writing, software
|
|
# distributed under the License is distributed on an "AS IS" BASIS,
|
|
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
# See the License for the specific language governing permissions and
|
|
# limitations under the License.
|
|
|
|
import queue
|
|
import threading
|
|
from pathlib import Path
|
|
|
|
from watchdog.utils import BaseThread
|
|
from watchdog.utils.bricks import SkipRepeatsQueue
|
|
|
|
DEFAULT_EMITTER_TIMEOUT = 1 # in seconds.
|
|
DEFAULT_OBSERVER_TIMEOUT = 1 # in seconds.
|
|
|
|
|
|
# Collection classes
|
|
class EventQueue(SkipRepeatsQueue):
|
|
"""Thread-safe event queue based on a special queue that skips adding
|
|
the same event (:class:`FileSystemEvent`) multiple times consecutively.
|
|
Thus avoiding dispatching multiple event handling
|
|
calls when multiple identical events are produced quicker than an observer
|
|
can consume them.
|
|
"""
|
|
|
|
|
|
class ObservedWatch:
|
|
"""An scheduled watch.
|
|
|
|
:param path:
|
|
Path string.
|
|
:param recursive:
|
|
``True`` if watch is recursive; ``False`` otherwise.
|
|
"""
|
|
|
|
def __init__(self, path, recursive):
|
|
if isinstance(path, Path):
|
|
self._path = str(path)
|
|
else:
|
|
self._path = path
|
|
self._is_recursive = recursive
|
|
|
|
@property
|
|
def path(self):
|
|
"""The path that this watch monitors."""
|
|
return self._path
|
|
|
|
@property
|
|
def is_recursive(self):
|
|
"""Determines whether subdirectories are watched for the path."""
|
|
return self._is_recursive
|
|
|
|
@property
|
|
def key(self):
|
|
return self.path, self.is_recursive
|
|
|
|
def __eq__(self, watch):
|
|
return self.key == watch.key
|
|
|
|
def __ne__(self, watch):
|
|
return self.key != watch.key
|
|
|
|
def __hash__(self):
|
|
return hash(self.key)
|
|
|
|
def __repr__(self):
|
|
return "<%s: path=%s, is_recursive=%s>" % (
|
|
type(self).__name__, self.path, self.is_recursive)
|
|
|
|
|
|
# Observer classes
|
|
class EventEmitter(BaseThread):
|
|
"""
|
|
Producer thread base class subclassed by event emitters
|
|
that generate events and populate a queue with them.
|
|
|
|
:param event_queue:
|
|
The event queue to populate with generated events.
|
|
:type event_queue:
|
|
:class:`watchdog.events.EventQueue`
|
|
:param watch:
|
|
The watch to observe and produce events for.
|
|
:type watch:
|
|
:class:`ObservedWatch`
|
|
:param timeout:
|
|
Timeout (in seconds) between successive attempts at reading events.
|
|
:type timeout:
|
|
``float``
|
|
"""
|
|
|
|
def __init__(self, event_queue, watch, timeout=DEFAULT_EMITTER_TIMEOUT):
|
|
BaseThread.__init__(self)
|
|
self._event_queue = event_queue
|
|
self._watch = watch
|
|
self._timeout = timeout
|
|
|
|
@property
|
|
def timeout(self):
|
|
"""
|
|
Blocking timeout for reading events.
|
|
"""
|
|
return self._timeout
|
|
|
|
@property
|
|
def watch(self):
|
|
"""
|
|
The watch associated with this emitter.
|
|
"""
|
|
return self._watch
|
|
|
|
def queue_event(self, event):
|
|
"""
|
|
Queues a single event.
|
|
|
|
:param event:
|
|
Event to be queued.
|
|
:type event:
|
|
An instance of :class:`watchdog.events.FileSystemEvent`
|
|
or a subclass.
|
|
"""
|
|
self._event_queue.put((event, self.watch))
|
|
|
|
def queue_events(self, timeout):
|
|
"""Override this method to populate the event queue with events
|
|
per interval period.
|
|
|
|
:param timeout:
|
|
Timeout (in seconds) between successive attempts at
|
|
reading events.
|
|
:type timeout:
|
|
``float``
|
|
"""
|
|
|
|
def run(self):
|
|
while self.should_keep_running():
|
|
self.queue_events(self.timeout)
|
|
|
|
|
|
class EventDispatcher(BaseThread):
|
|
"""
|
|
Consumer thread base class subclassed by event observer threads
|
|
that dispatch events from an event queue to appropriate event handlers.
|
|
|
|
:param timeout:
|
|
Event queue blocking timeout (in seconds).
|
|
:type timeout:
|
|
``float``
|
|
"""
|
|
|
|
def __init__(self, timeout=DEFAULT_OBSERVER_TIMEOUT):
|
|
BaseThread.__init__(self)
|
|
self._event_queue = EventQueue()
|
|
self._timeout = timeout
|
|
|
|
@property
|
|
def timeout(self):
|
|
"""Event queue block timeout."""
|
|
return self._timeout
|
|
|
|
@property
|
|
def event_queue(self):
|
|
"""The event queue which is populated with file system events
|
|
by emitters and from which events are dispatched by a dispatcher
|
|
thread."""
|
|
return self._event_queue
|
|
|
|
def dispatch_events(self, event_queue, timeout):
|
|
"""Override this method to consume events from an event queue, blocking
|
|
on the queue for the specified timeout before raising :class:`queue.Empty`.
|
|
|
|
:param event_queue:
|
|
Event queue to populate with one set of events.
|
|
:type event_queue:
|
|
:class:`EventQueue`
|
|
:param timeout:
|
|
Interval period (in seconds) to wait before timing out on the
|
|
event queue.
|
|
:type timeout:
|
|
``float``
|
|
:raises:
|
|
:class:`queue.Empty`
|
|
"""
|
|
|
|
def run(self):
|
|
while self.should_keep_running():
|
|
try:
|
|
self.dispatch_events(self.event_queue, self.timeout)
|
|
except queue.Empty:
|
|
continue
|
|
|
|
|
|
class BaseObserver(EventDispatcher):
|
|
"""Base observer."""
|
|
|
|
def __init__(self, emitter_class, timeout=DEFAULT_OBSERVER_TIMEOUT):
|
|
EventDispatcher.__init__(self, timeout)
|
|
self._emitter_class = emitter_class
|
|
self._lock = threading.RLock()
|
|
self._watches = set()
|
|
self._handlers = dict()
|
|
self._emitters = set()
|
|
self._emitter_for_watch = dict()
|
|
|
|
def _add_emitter(self, emitter):
|
|
self._emitter_for_watch[emitter.watch] = emitter
|
|
self._emitters.add(emitter)
|
|
|
|
def _remove_emitter(self, emitter):
|
|
del self._emitter_for_watch[emitter.watch]
|
|
self._emitters.remove(emitter)
|
|
emitter.stop()
|
|
try:
|
|
emitter.join()
|
|
except RuntimeError:
|
|
pass
|
|
|
|
def _clear_emitters(self):
|
|
for emitter in self._emitters:
|
|
emitter.stop()
|
|
for emitter in self._emitters:
|
|
try:
|
|
emitter.join()
|
|
except RuntimeError:
|
|
pass
|
|
self._emitters.clear()
|
|
self._emitter_for_watch.clear()
|
|
|
|
def _add_handler_for_watch(self, event_handler, watch):
|
|
if watch not in self._handlers:
|
|
self._handlers[watch] = set()
|
|
self._handlers[watch].add(event_handler)
|
|
|
|
def _remove_handlers_for_watch(self, watch):
|
|
del self._handlers[watch]
|
|
|
|
@property
|
|
def emitters(self):
|
|
"""Returns event emitter created by this observer."""
|
|
return self._emitters
|
|
|
|
def start(self):
|
|
for emitter in self._emitters.copy():
|
|
try:
|
|
emitter.start()
|
|
except Exception:
|
|
self._remove_emitter(emitter)
|
|
raise
|
|
super().start()
|
|
|
|
def schedule(self, event_handler, path, recursive=False):
|
|
"""
|
|
Schedules watching a path and calls appropriate methods specified
|
|
in the given event handler in response to file system events.
|
|
|
|
:param event_handler:
|
|
An event handler instance that has appropriate event handling
|
|
methods which will be called by the observer in response to
|
|
file system events.
|
|
:type event_handler:
|
|
:class:`watchdog.events.FileSystemEventHandler` or a subclass
|
|
:param path:
|
|
Directory path that will be monitored.
|
|
:type path:
|
|
``str``
|
|
:param recursive:
|
|
``True`` if events will be emitted for sub-directories
|
|
traversed recursively; ``False`` otherwise.
|
|
:type recursive:
|
|
``bool``
|
|
:return:
|
|
An :class:`ObservedWatch` object instance representing
|
|
a watch.
|
|
"""
|
|
with self._lock:
|
|
watch = ObservedWatch(path, recursive)
|
|
self._add_handler_for_watch(event_handler, watch)
|
|
|
|
# If we don't have an emitter for this watch already, create it.
|
|
if self._emitter_for_watch.get(watch) is None:
|
|
emitter = self._emitter_class(event_queue=self.event_queue,
|
|
watch=watch,
|
|
timeout=self.timeout)
|
|
self._add_emitter(emitter)
|
|
if self.is_alive():
|
|
emitter.start()
|
|
self._watches.add(watch)
|
|
return watch
|
|
|
|
def add_handler_for_watch(self, event_handler, watch):
|
|
"""Adds a handler for the given watch.
|
|
|
|
:param event_handler:
|
|
An event handler instance that has appropriate event handling
|
|
methods which will be called by the observer in response to
|
|
file system events.
|
|
:type event_handler:
|
|
:class:`watchdog.events.FileSystemEventHandler` or a subclass
|
|
:param watch:
|
|
The watch to add a handler for.
|
|
:type watch:
|
|
An instance of :class:`ObservedWatch` or a subclass of
|
|
:class:`ObservedWatch`
|
|
"""
|
|
with self._lock:
|
|
self._add_handler_for_watch(event_handler, watch)
|
|
|
|
def remove_handler_for_watch(self, event_handler, watch):
|
|
"""Removes a handler for the given watch.
|
|
|
|
:param event_handler:
|
|
An event handler instance that has appropriate event handling
|
|
methods which will be called by the observer in response to
|
|
file system events.
|
|
:type event_handler:
|
|
:class:`watchdog.events.FileSystemEventHandler` or a subclass
|
|
:param watch:
|
|
The watch to remove a handler for.
|
|
:type watch:
|
|
An instance of :class:`ObservedWatch` or a subclass of
|
|
:class:`ObservedWatch`
|
|
"""
|
|
with self._lock:
|
|
self._handlers[watch].remove(event_handler)
|
|
|
|
def unschedule(self, watch):
|
|
"""Unschedules a watch.
|
|
|
|
:param watch:
|
|
The watch to unschedule.
|
|
:type watch:
|
|
An instance of :class:`ObservedWatch` or a subclass of
|
|
:class:`ObservedWatch`
|
|
"""
|
|
with self._lock:
|
|
emitter = self._emitter_for_watch[watch]
|
|
del self._handlers[watch]
|
|
self._remove_emitter(emitter)
|
|
self._watches.remove(watch)
|
|
|
|
def unschedule_all(self):
|
|
"""Unschedules all watches and detaches all associated event
|
|
handlers."""
|
|
with self._lock:
|
|
self._handlers.clear()
|
|
self._clear_emitters()
|
|
self._watches.clear()
|
|
|
|
def on_thread_stop(self):
|
|
self.unschedule_all()
|
|
|
|
def dispatch_events(self, event_queue, timeout):
|
|
event, watch = event_queue.get(block=True, timeout=timeout)
|
|
|
|
with self._lock:
|
|
# To allow unschedule/stop and safe removal of event handlers
|
|
# within event handlers itself, check if the handler is still
|
|
# registered after every dispatch.
|
|
for handler in list(self._handlers.get(watch, [])):
|
|
if handler in self._handlers.get(watch, []):
|
|
handler.dispatch(event)
|
|
event_queue.task_done()
|