Delete/overwrite symlinks better

Previously, when deleting a symlink that points to an xLO, we'd clean
up the xLO's segments then delete the symlink, leaving the xLO itself
busted.

Similar trouble would come from overwriting a symlink pointing to an
xLO. Check for a Content-Location in the HEAD response and leave such
segments.

Co-Authored-By: Clay Gerrard <clay.gerrard@gmail.com>
Change-Id: I45b210cf380a68bd88187c91fa2d63a8b2bb709b

swiftclient/service.py

@@ -2070,7 +2070,8 @@ class SwiftService(object):
                             'status': 'skipped-changed'
                         })
                         return res
-                    if not options['leave_segments']:
+                    if not options['leave_segments'] and not headers.get(
+                            'content-location'):
                         old_manifest = headers.get('x-object-manifest')
                         if is_slo:
                             old_slo_manifest_paths.extend(
@@ -2515,7 +2516,8 @@ class SwiftService(object):
             if not options['leave_segments']:
                 try:
                     headers = conn.head_object(container, obj,
-                                               headers=_headers)
+                                               headers=_headers,
+                                               query_string='symlink=get')
                     old_manifest = headers.get('x-object-manifest')
                     if config_true_value(headers.get('x-static-large-object')):
                         query_string = 'multipart-manifest=delete'

tests/unit/test_service.py

@@ -312,8 +312,8 @@ class TestServiceDelete(_TestServiceBase):
         s = SwiftService()
         r = s._delete_object(mock_conn, 'test_c', 'test_o', self.opts, mock_q)
 
-        mock_conn.head_object.assert_called_once_with('test_c', 'test_o',
-                                                      headers={})
+        mock_conn.head_object.assert_called_once_with(
+            'test_c', 'test_o', query_string='symlink=get', headers={})
         mock_conn.delete_object.assert_called_once_with(
             'test_c', 'test_o', query_string=None, response_dict={},
             headers={}
@@ -335,7 +335,8 @@ class TestServiceDelete(_TestServiceBase):
         r = s._delete_object(mock_conn, 'test_c', 'test_o', opt_c, mock_q)
 
         mock_conn.head_object.assert_called_once_with(
-            'test_c', 'test_o', headers={'Skip-Middleware': 'Test'})
+            'test_c', 'test_o', headers={'Skip-Middleware': 'Test'},
+            query_string='symlink=get')
         mock_conn.delete_object.assert_called_once_with(
             'test_c', 'test_o', query_string=None, response_dict={},
             headers={'Skip-Middleware': 'Test'}
@@ -362,8 +363,8 @@ class TestServiceDelete(_TestServiceBase):
         r = s._delete_object(mock_conn, 'test_c', 'test_o', self.opts, mock_q)
         after = time.time()
 
-        mock_conn.head_object.assert_called_once_with('test_c', 'test_o',
-                                                      headers={})
+        mock_conn.head_object.assert_called_once_with(
+            'test_c', 'test_o', query_string='symlink=get', headers={})
         mock_conn.delete_object.assert_called_once_with(
             'test_c', 'test_o', query_string=None, response_dict={},
             headers={}
@@ -389,8 +390,8 @@ class TestServiceDelete(_TestServiceBase):
         s = SwiftService()
         r = s._delete_object(mock_conn, 'test_c', 'test_o', self.opts, mock_q)
 
-        mock_conn.head_object.assert_called_once_with('test_c', 'test_o',
-                                                      headers={})
+        mock_conn.head_object.assert_called_once_with(
+            'test_c', 'test_o', query_string='symlink=get', headers={})
         mock_conn.delete_object.assert_called_once_with(
             'test_c', 'test_o',
             query_string='multipart-manifest=delete',

tests/unit/test_shell.py

@@ -832,6 +832,35 @@ class TestShell(unittest.TestCase):
             sorted(connection.return_value.delete_object.mock_calls)
         )
 
+    @mock.patch('swiftclient.service.Connection')
+    def test_upload_over_symlink_to_slo(self, connection):
+        # Upload delete existing segments
+        connection.return_value.head_container.return_value = {
+            'x-storage-policy': 'one'}
+        connection.return_value.attempts = 0
+        connection.return_value.head_object.side_effect = [
+            {'x-static-large-object': 'true',
+             'content-location': '/v1/a/c/manifest',
+             'content-length': '2'},
+        ]
+        connection.return_value.get_object.return_value = (
+            {'content-location': '/v1/a/c/manifest'},
+            b'[{"name": "container1/old_seg1"},'
+            b' {"name": "container2/old_seg2"}]'
+        )
+        connection.return_value.put_object.return_value = EMPTY_ETAG
+        connection.return_value.delete_object.return_value = None
+        argv = ["", "upload", "container", self.tmpfile]
+        swiftclient.shell.main(argv)
+        connection.return_value.put_object.assert_called_with(
+            'container',
+            self.tmpfile.lstrip('/'),
+            mock.ANY,
+            content_length=0,
+            headers={'x-object-meta-mtime': mock.ANY},
+            response_dict={})
+        self.assertEqual([], connection.return_value.delete_object.mock_calls)
+
     @mock.patch('swiftclient.service.Connection')
     def test_upload_leave_slo_segments(self, connection):
         # Test upload overwriting a manifest respects --leave-segments