Ignore files in the devices directory when auditing objects

The object auditor raises an exception if there are some files in
/srv/node (or any other defined "devices" directory). This change
simply skips any file in the devices directory when generating
locations for the object auditor.

Change-Id: I934594994adc577799723edb6c5648685682a9e7

swift/obj/diskfile.py

@@ -296,7 +296,15 @@ def object_audit_location_generator(devices, mount_check=True, logger=None,
                     _('Skipping %s as it is not mounted'), device)
             continue
         # loop through object dirs for all policies
-        for dir_ in os.listdir(os.path.join(devices, device)):
+        device_dir = os.path.join(devices, device)
+        try:
+            dirs = os.listdir(device_dir)
+        except OSError as e:
+            if logger:
+                logger.debug(
+                    _('Skipping %s: %s') % (device_dir, e.strerror))
+            continue
+        for dir_ in dirs:
             if not dir_.startswith(DATADIR_BASE):
                 continue
             try:

test/unit/obj/test_diskfile.py

@@ -402,6 +402,36 @@ def mock_ismount(path):
                     'Skipping %s as it is not mounted',
                     'sdq')
 
+    def test_skipping_files(self):
+        with temptree([]) as tmpdir:
+            os.makedirs(os.path.join(tmpdir, "sdp", "objects",
+                                     "2607", "df3",
+                                     "ec2871fe724411f91787462f97d30df3"))
+            with open(os.path.join(tmpdir, "garbage"), "wb") as fh:
+                fh.write('')
+
+            locations = [
+                (loc.path, loc.device, loc.partition, loc.policy)
+                for loc in diskfile.object_audit_location_generator(
+                    devices=tmpdir, mount_check=False)]
+
+            self.assertEqual(
+                locations,
+                [(os.path.join(tmpdir, "sdp", "objects",
+                               "2607", "df3",
+                               "ec2871fe724411f91787462f97d30df3"),
+                  "sdp", "2607", POLICIES[0])])
+
+            # Do it again, this time with a logger.
+            ml = mock.MagicMock()
+            locations = [
+                (loc.path, loc.device, loc.partition, loc.policy)
+                for loc in diskfile.object_audit_location_generator(
+                    devices=tmpdir, mount_check=False, logger=ml)]
+            ml.debug.assert_called_once_with(
+                'Skipping %s: Not a directory' %
+                os.path.join(tmpdir, "garbage"))
+
     def test_only_catch_expected_errors(self):
         # Crazy exceptions should still escape object_audit_location_generator
         # so that errors get logged and a human can see what's going wrong;