From 39105d2a0a51af6cc2d9251eada364127273e550 Mon Sep 17 00:00:00 2001
From: Kushal Agrawal <kushal.agrawal@nokia.com>
Date: Tue, 8 May 2018 16:16:09 +0530
Subject: [PATCH] Retain existing blob in case of pre_upload_hook or save fails

While re-uploading blob if pre_upload_hook or store_api throws
exception, Existing content needs to be retained.

Change-Id: I51effe4c76de9a353dec99c634c173840c792198
---
 glare/engine.py                     | 15 ++++++++++++++-
 glare/tests/sample_artifact.py      | 18 ++++++++++++++++++
 glare/tests/unit/api/test_upload.py | 10 ++++++++++
 3 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/glare/engine.py b/glare/engine.py
index 6913234..3fb62f1 100644
--- a/glare/engine.py
+++ b/glare/engine.py
@@ -581,6 +581,11 @@ class Engine(object):
                     'status': existing_blob_status}
                 raise exception.Conflict(message=msg)
             utils.validate_change_allowed(af, field_name)
+
+            if existing_blob is not None:
+                blob_info = deepcopy(existing_blob)
+                blob_info['status'] = 'saving'
+
             blob_info['size'] = self._calculate_allowed_space(
                 context, af, field_name, content_length, blob_key)
 
@@ -628,8 +633,16 @@ class Engine(object):
             # if upload failed remove blob from db and storage
             with excutils.save_and_reraise_exception(logger=LOG):
                 LOG.error("Exception occured: %s", Exception)
+                # delete created blob_info in case of blob_data upload fails.
+                if existing_blob is None:
+                    blob_info = None
+                else:
+                    # Update size of blob_data to previous blob and
+                    # Mark existing blob status to active.
+                    blob_info['size'] = existing_blob['size']
+                    blob_info['status'] = 'active'
                 self._save_blob_info(
-                    context, af, field_name, blob_key, None)
+                    context, af, field_name, blob_key, blob_info)
 
         LOG.info("Successfully finished blob uploading for artifact "
                  "%(artifact)s blob field %(blob)s.",
diff --git a/glare/tests/sample_artifact.py b/glare/tests/sample_artifact.py
index 3ef731b..c3df5df 100644
--- a/glare/tests/sample_artifact.py
+++ b/glare/tests/sample_artifact.py
@@ -13,9 +13,12 @@
 # under the License.
 
 """Sample artifact object for testing purposes"""
+import io
 
+from glare.common.utils import CooperativeReader
 from oslo_versionedobjects import fields
 
+from glare.common.exception import GlareException
 from glare.objects import base as base_artifact
 from glare.objects.meta import fields as glare_fields
 from glare.objects.meta import validators
@@ -143,6 +146,21 @@ class SampleArtifact(base_artifact.BaseArtifact):
     def get_display_type_name(cls):
         return "Sample Artifact"
 
+    @classmethod
+    def pre_upload_hook(cls, context, af, field_name, blob_key, fd):
+        flobj = io.BytesIO(CooperativeReader(fd).read())
+        data = flobj.read()
+        print("Data in pre_upload_hook: %s" % data)
+        if data == b'invalid_data':
+            raise GlareException("Invalid Data found")
+        # Try to seek same fd to 0.
+        try:
+            fd.seek(0)
+        except Exception:  # catch Exception in case fd is non-seekable.
+            flobj.seek(0)
+            return flobj
+        return fd
+
     def to_dict(self):
         res = self.obj_to_primitive()['versioned_object.data']
         res['__some_meta_information__'] = res['name'].upper()
diff --git a/glare/tests/unit/api/test_upload.py b/glare/tests/unit/api/test_upload.py
index e2f7ffd..9feaf77 100644
--- a/glare/tests/unit/api/test_upload.py
+++ b/glare/tests/unit/api/test_upload.py
@@ -66,6 +66,16 @@ class TestArtifactUpload(base.BaseTestArtifactAPI):
         self.assertEqual(5, artifact['blob']['size'])
         self.assertEqual('active', artifact['blob']['status'])
 
+        # failed in pre_upload_hook validation and retain the existing data
+        self.assertRaises(exc.GlareException, self.controller.upload_blob,
+                          self.req, 'sample_artifact',
+                          self.sample_artifact['id'], 'blob',
+                          BytesIO(b'invalid_data'), 'application/octet-stream')
+        artifact = self.controller.show(self.req, 'sample_artifact',
+                                        self.sample_artifact['id'])
+        self.assertEqual(5, artifact['blob']['size'])
+        self.assertEqual('active', artifact['blob']['status'])
+
     def test_upload_saving_blob(self):
         self.controller.upload_blob(
             self.req, 'sample_artifact', self.sample_artifact['id'], 'blob',