Fix retry of broken encrypted upload

- Resolves #61

blobxfer/models/metadata.py

@@ -99,8 +99,12 @@ def get_md5_from_metadata(ase):
     # md5 in blobxfer extensions
     md5 = None
     if ase.is_encrypted:
-        md5 = ase.encryption_metadata.blobxfer_extensions.\
-            pre_encrypted_content_md5
+        try:
+            md5 = ase.encryption_metadata.blobxfer_extensions.\
+                pre_encrypted_content_md5
+        except AttributeError:
+            # this can happen if partial metadata is present
+            md5 = None
     if blobxfer.util.is_none_or_empty(md5):
         md5 = ase.md5
     return md5

tests/test_blobxfer_models_metadata.py

@@ -13,6 +13,12 @@ import pytest
 import blobxfer.models.metadata as md
 
 
+class AseAE(object):
+    def __init__(self):
+        self.is_encrypted = True
+        self.md5 = 'aseae'
+
+
 def test_get_md5_from_metadata():
     ase = mock.MagicMock()
     ase.is_encrypted = True
@@ -24,6 +30,10 @@ def test_get_md5_from_metadata():
     ase.md5 = 'md5'
     assert md.get_md5_from_metadata(ase) == 'md5'
 
+    ase = AseAE()
+    asemd5 = md.get_md5_from_metadata(ase)
+    assert asemd5 == 'aseae'
+
 
 def test_generate_fileattr_metadata():
     with mock.patch('blobxfer.util.on_windows', return_value=True):