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:

src/documents/tests/test_management_consumer.py

@@ -7,8 +7,9 @@ from unittest import mock
 
 from django.conf import settings
 from django.core.management import call_command, CommandError
-from django.test import override_settings, TransactionTestCase
+from django.test import override_settings, TransactionTestCase, TestCase
 
+from documents.management.commands.document_consumer import _test_inotify
 from documents.models import Tag
 from documents.consumer import ConsumerError
 from documents.management.commands import document_consumer
@@ -260,3 +261,27 @@ class TestConsumerTags(DirectoriesMixin, ConsumerMixin, TransactionTestCase):
     @override_settings(CONSUMER_POLLING=1)
     def test_consume_file_with_path_tags_polling(self):
         self.test_consume_file_with_path_tags()
+
+
+class TestInotify(DirectoriesMixin, TestCase):
+
+    def test_inotify(self):
+        self.assertTrue(_test_inotify(self.dirs.consumption_dir))
+
+    @mock.patch("documents.management.commands.document_consumer.Path.touch")
+    def test_inotify_error(self, m):
+        m.side_effect = OSError("Permission error")
+        self.assertFalse(_test_inotify(self.dirs.consumption_dir))
+
+    @mock.patch("documents.management.commands.document_consumer.Command.handle_polling")
+    @mock.patch("documents.management.commands.document_consumer.Command.handle_inotify")
+    @mock.patch("documents.management.commands.document_consumer._test_inotify")
+    def test_polling_fallback(self, test_inotify, handle_inotify, handle_polling):
+        test_inotify.return_value = False
+
+        cmd = document_consumer.Command()
+        cmd.handle(directory=settings.CONSUMPTION_DIR, oneshot=False)
+
+        test_inotify.assert_called_once()
+        handle_polling.assert_called_once()
+        handle_inotify.assert_not_called()