fixes #351

src/documents/management/commands/document_consumer.py

@@ -5,7 +5,6 @@ from time import sleep
 
 from django.conf import settings
 from django.core.management.base import BaseCommand, CommandError
-from django.utils.text import slugify
 from django_q.tasks import async_task
 from watchdog.events import FileSystemEventHandler
 from watchdog.observers.polling import PollingObserver
@@ -71,6 +70,31 @@ def _consume(filepath):
             "Error while consuming document: {}".format(e))
 
 
+def _test_inotify(directory):
+    if not INotify:
+        return False
+
+    test_file = os.path.join(directory, "__inotify_test_file__")
+    inotify = INotify()
+    descriptor = None
+    try:
+        inotify_flags = flags.CLOSE_WRITE | flags.MOVED_TO
+        descriptor = inotify.add_watch(directory, inotify_flags)
+        Path(test_file).touch()
+        events = inotify.read(timeout=1000)
+        return len(events) == 1
+    except Exception as e:
+        logger.warning(
+            f"Error while checking inotify availability: {str(e)}")
+        return False
+    finally:
+        if descriptor:
+            inotify.rm_watch(descriptor)
+        inotify.close()
+        if os.path.isfile(test_file):
+            os.unlink(test_file)
+
+
 def _consume_wait_unmodified(file, num_tries=20, wait_time=1):
     mtime = -1
     current_try = 0
@@ -154,17 +178,25 @@ class Command(BaseCommand):
         if options["oneshot"]:
             return
 
-        if settings.CONSUMER_POLLING == 0 and INotify:
-            self.handle_inotify(directory, recursive)
+        if settings.CONSUMER_POLLING == 0:
+            if _test_inotify(directory):
+                self.handle_inotify(directory, recursive)
+            else:
+                logger.warning(
+                    f"Inotify notifications are not available on {directory}, "
+                    f"falling back to polling every 10 seconds")
+                self.handle_polling(
+                    directory, recursive, 10)
         else:
-            self.handle_polling(directory, recursive)
+            self.handle_polling(
+                directory, recursive, settings.CONSUMER_POLLING)
 
         logger.debug("Consumer exiting.")
 
-    def handle_polling(self, directory, recursive):
+    def handle_polling(self, directory, recursive, timeout):
         logging.getLogger(__name__).info(
             f"Polling directory for changes: {directory}")
-        self.observer = PollingObserver(timeout=settings.CONSUMER_POLLING)
+        self.observer = PollingObserver(timeout=timeout)
         self.observer.schedule(Handler(), directory, recursive=recursive)
         self.observer.start()
         try: