Add --smoothing parameter for watchmedo --command to smooth over / ignore multiple triggering events.

src/watchdog/observers/api.py

@@ -51,6 +51,7 @@
 
 from __future__ import with_statement
 import threading
+import time
 
 try:
     import queue  # IGNORE:F0401
@@ -62,6 +63,7 @@
 
 DEFAULT_EMITTER_TIMEOUT = 1    # in seconds.
 DEFAULT_OBSERVER_TIMEOUT = 1   # in seconds.
+DEFAULT_SMOOTHING_TIMEOUT = 0  # in seconds.
 
 
 # Collection classes
@@ -247,14 +249,15 @@ class BaseObserver(EventDispatcher):
 
     """Base observer."""
 
-    def __init__(self, emitter_class, timeout=DEFAULT_OBSERVER_TIMEOUT):
+    def __init__(self, emitter_class, timeout=DEFAULT_OBSERVER_TIMEOUT, smoothing=DEFAULT_SMOOTHING_TIMEOUT):
         EventDispatcher.__init__(self, timeout)
         self._emitter_class = emitter_class
         self._lock = threading.Lock()
         self._watches = set()
         self._handlers = dict()
         self._emitters = set()
         self._emitter_for_watch = dict()
+        self._smoothing = smoothing
 
     def _add_emitter(self, emitter):
         self._emitter_for_watch[emitter.watch] = emitter
@@ -404,6 +407,18 @@ def _dispatch_event(self, event, watch):
 
     def dispatch_events(self, event_queue, timeout):
         event, watch = event_queue.get(block=True, timeout=timeout)
+
+        # Sleep for the specified amount of time, then clean out the
+        # event queue, and then dispatch the event.
+        if self._smoothing > 0:
+            time.sleep(self._smoothing)
+
+            if not event_queue.empty():
+                print("Smoothing over / ignoring {0} filesystem events that arrived after the triggering event.".format(event_queue.qsize()))
+
+            while not event_queue.empty():
+                event_queue.get_nowait()
+
         try:
             self._dispatch_event(event, watch)
         except KeyError:

src/watchdog/observers/fsevents.py

@@ -46,7 +46,8 @@
     BaseObserver,
     EventEmitter,
     DEFAULT_EMITTER_TIMEOUT,
-    DEFAULT_OBSERVER_TIMEOUT
+    DEFAULT_OBSERVER_TIMEOUT,
+    DEFAULT_SMOOTHING_TIMEOUT
 )
 
 
@@ -143,9 +144,10 @@ def callback(pathnames, flags, emitter=self):
 
 class FSEventsObserver(BaseObserver):
 
-    def __init__(self, timeout=DEFAULT_OBSERVER_TIMEOUT):
+    def __init__(self, timeout=DEFAULT_OBSERVER_TIMEOUT, smoothing=DEFAULT_SMOOTHING_TIMEOUT):
         BaseObserver.__init__(self, emitter_class=FSEventsEmitter,
-                              timeout=timeout)
+                              timeout=timeout,
+                              smoothing=smoothing)
 
     def schedule(self, event_handler, path, recursive=False):
         # Python 2/3 compat

src/watchdog/observers/inotify.py

@@ -77,7 +77,8 @@
     EventEmitter,
     BaseObserver,
     DEFAULT_EMITTER_TIMEOUT,
-    DEFAULT_OBSERVER_TIMEOUT
+    DEFAULT_OBSERVER_TIMEOUT,
+    DEFAULT_SMOOTHING_TIMEOUT
 )
 
 from watchdog.events import (
@@ -183,6 +184,7 @@ class InotifyObserver(BaseObserver):
     calls to event handlers.
     """
 
-    def __init__(self, timeout=DEFAULT_OBSERVER_TIMEOUT):
+    def __init__(self, timeout=DEFAULT_OBSERVER_TIMEOUT, smoothing=DEFAULT_SMOOTHING_TIMEOUT):
         BaseObserver.__init__(self, emitter_class=InotifyEmitter,
-                              timeout=timeout)
+                              timeout=timeout,
+                              smoothing=smoothing)

src/watchdog/observers/kqueue.py

@@ -100,7 +100,8 @@
     BaseObserver,
     EventEmitter,
     DEFAULT_OBSERVER_TIMEOUT,
-    DEFAULT_EMITTER_TIMEOUT
+    DEFAULT_EMITTER_TIMEOUT,
+    DEFAULT_SMOOTHING_TIMEOUT
 )
 
 from watchdog.utils.dirsnapshot import DirectorySnapshot
@@ -722,5 +723,5 @@ class KqueueObserver(BaseObserver):
     calls to event handlers.
     """
 
-    def __init__(self, timeout=DEFAULT_OBSERVER_TIMEOUT):
-        BaseObserver.__init__(self, emitter_class=KqueueEmitter, timeout=timeout)
+    def __init__(self, timeout=DEFAULT_OBSERVER_TIMEOUT, smoothing=DEFAULT_SMOOTHING_TIMEOUT):
+        BaseObserver.__init__(self, emitter_class=KqueueEmitter, timeout=timeout, smoothing=DEFAULT_SMOOTHING_TIMEOUT)

src/watchdog/observers/polling.py

@@ -44,7 +44,8 @@
     EventEmitter,
     BaseObserver,
     DEFAULT_OBSERVER_TIMEOUT,
-    DEFAULT_EMITTER_TIMEOUT
+    DEFAULT_EMITTER_TIMEOUT,
+    DEFAULT_SMOOTHING_TIMEOUT
 )
 
 from watchdog.events import (
@@ -119,8 +120,8 @@ class PollingObserver(BaseObserver):
     system changes.
     """
 
-    def __init__(self, timeout=DEFAULT_OBSERVER_TIMEOUT):
-        BaseObserver.__init__(self, emitter_class=PollingEmitter, timeout=timeout)
+    def __init__(self, timeout=DEFAULT_OBSERVER_TIMEOUT, smoothing=DEFAULT_SMOOTHING_TIMEOUT):
+        BaseObserver.__init__(self, emitter_class=PollingEmitter, timeout=timeout, smoothing=smoothing)
 
 
 class PollingObserverVFS(BaseObserver):

src/watchdog/observers/read_directory_changes.py

@@ -47,7 +47,8 @@
     EventEmitter,
     BaseObserver,
     DEFAULT_OBSERVER_TIMEOUT,
-    DEFAULT_EMITTER_TIMEOUT
+    DEFAULT_EMITTER_TIMEOUT,
+    DEFAULT_SMOOTHING_TIMEOUT
 )
 
 from watchdog.events import (
@@ -138,10 +139,11 @@ class WindowsApiObserver(BaseObserver):
     calls to event handlers.
     """
 
-    def __init__(self, timeout=DEFAULT_OBSERVER_TIMEOUT):
+    def __init__(self, timeout=DEFAULT_OBSERVER_TIMEOUT, smoothing=DEFAULT_SMOOTHING_TIMEOUT):
         BaseObserver.__init__(self,
                               emitter_class=WindowsApiEmitter,
-                              timeout=timeout)
+                              timeout=timeout,
+                              smoothing=smoothing)
 
 
 def _generate_sub_created_events_for(src_dir_path):

src/watchdog/watchmedo.py

@@ -417,6 +417,10 @@ def log(args):
      action='store_true',
      default=False,
      help="Ignore events that happen while the previous process is still running")
+@arg('-s', '--smoothing',
+     dest='smoothing',
+     default=0,
+     help='gather and ignore this many seconds worth of filesystem events after the initial event before running the shell command')
 def shell_command(args):
     """
     Subcommand to execute shell commands in response to file system events.
@@ -438,7 +442,7 @@ def shell_command(args):
                                 ignore_directories=args.ignore_directories,
                                 wait_for_process=args.wait_for_process,
                                 no_parallel_processes=args.no_parallel_processes)
-    observer = Observer(timeout=args.timeout)
+    observer = Observer(timeout=args.timeout, smoothing=args.smoothing)
     observe_with(observer, handler, args.directories, args.recursive)