Support for deleting images stored as SLO in Swift

When an image is deleted, the image data is not being deleted
completely if it is stored as static large object(SLO). Only the
manifest is deleted leaving behind all the segments. This leads to
stale data in swift cluster.

This change attempts to delete the SLO in the following way:
 1. Identify a SLO with 'x-static-large-object' header on an object
 2. Delete the SLO, both manifest and the segments, using the
 query string 'multipart-manifest=delete' while deleting the object

Closes-Bug: 1425617

Change-Id: Id2cd3b63ca88d66c5e7435b528ba75fa3c2cbb1c

1 files changed, 23 insertions, 4 deletions

diff --git a/glance_store/_drivers/swift/store.py b/glance_store/_drivers/swift/store.py
index 9f1995c..30b69f3 100644
--- a/glance_store/_drivers/swift/store.py
+++ b/glance_store/_drivers/swift/store.py
@@ -22,6 +22,7 @@ import math
 
 from oslo.config import cfg
 from oslo.utils import excutils
+import six
 import six.moves.urllib.parse as urlparse
 import swiftclient
 import urllib
@@ -373,6 +374,14 @@ def Store(conf):
 Store.OPTIONS = _SWIFT_OPTS + sutils.swift_opts
 
 
+def _is_slo(slo_header):
+    if (slo_header is not None and isinstance(slo_header, six.string_types)
+            and slo_header.lower() == 'true'):
+        return True
+
+    return False
+
+
 class BaseStore(driver.Store):
 
     _CAPABILITIES = capabilities.BitMasks.RW_ACCESS
@@ -612,17 +621,27 @@ class BaseStore(driver.Store):
             # that means the object was uploaded in chunks/segments,
             # and we need to delete all the chunks as well as the
             # manifest.
-            manifest = None
+            dlo_manifest = None
+            slo_manifest = None
             try:
                 headers = connection.head_object(
                     location.container, location.obj)
-                manifest = headers.get('x-object-manifest')
+                dlo_manifest = headers.get('x-object-manifest')
+                slo_manifest = headers.get('x-static-large-object')
             except swiftclient.ClientException as e:
                 if e.http_status != httplib.NOT_FOUND:
                     raise
-            if manifest:
+
+            if _is_slo(slo_manifest):
+                # Delete the manifest as well as the segments
+                query_string = 'multipart-manifest=delete'
+                connection.delete_object(location.container, location.obj,
+                                         query_string=query_string)
+                return
+
+            if dlo_manifest:
                 # Delete all the chunks before the object manifest itself
-                obj_container, obj_prefix = manifest.split('/', 1)
+                obj_container, obj_prefix = dlo_manifest.split('/', 1)
                 segments = connection.get_container(
                     obj_container, prefix=obj_prefix)[1]
                 for segment in segments: