Add option to fail upload if remote file exists

The if-none-match header option with '*' is used in that case.
This is exposed as 'if_not_exist' in PithosClient.upload_object

Feature #3574

kamaki/clients/pithos/__init__.py

@@ -204,7 +204,6 @@ class PithosClient(PithosRestClient):
             format='json',
             hashmap=True,
             content_type=None,
-            etag=None,
             content_encoding=None,
             content_disposition=None,
             permissions=None,
@@ -216,7 +215,6 @@ class PithosClient(PithosRestClient):
             hashmap=True,
             content_type=content_type,
             json=json,
-            etag=etag,
             content_encoding=content_encoding,
             content_disposition=content_disposition,
             permissions=permissions,
@@ -293,6 +291,7 @@ class PithosClient(PithosRestClient):
             hash_cb=None,
             upload_cb=None,
             etag=None,
+            if_not_exist=None,
             content_encoding=None,
             content_disposition=None,
             content_type=None,
@@ -310,6 +309,11 @@ class PithosClient(PithosRestClient):
 
         :param etag: (str)
 
+        :param if_not_exist: (bool) If true, the file will be uploaded ONLY if
+            it does not exist remotely, otherwise the operation will fail.
+            Involves the case of an object with the same path is created while
+            the object is being uploaded.
+
         :param content_encoding: (str)
 
         :param content_disposition: (str)
@@ -342,7 +346,6 @@ class PithosClient(PithosRestClient):
             obj, hashmap,
             content_type=content_type,
             size=size,
-            etag=etag,
             content_encoding=content_encoding,
             content_disposition=content_disposition,
             permissions=sharing,
@@ -393,6 +396,8 @@ class PithosClient(PithosRestClient):
             format='json',
             hashmap=True,
             content_type=content_type,
+            if_etag_not_match='*' if if_not_exist else None,
+            etag=etag,
             json=hashmap,
             success=201)
 

kamaki/clients/pithos/test.py

@@ -835,7 +835,6 @@ class PithosClient(TestCase):
             json=dict(
                 hashes=['s0m3h@5h'] * num_of_blocks,
                 bytes=num_of_blocks * 4 * 1024 * 1024),
-            etag=None,
             content_encoding=None,
             content_type='application/octet-stream',
             content_disposition=None,
@@ -911,13 +910,18 @@ class PithosClient(TestCase):
         tmpFile.seek(0)
         kwargs = dict(
             etag='s0m3E74g',
+            if_not_exist=True,
             content_type=ctype,
             content_disposition=ctype + 'd15p051710n',
             public=True,
             content_encoding='802.11')
         self.client.upload_object(obj, tmpFile, **kwargs)
+        kwargs.pop('if_not_exist')
+        etag = kwargs.pop('etag')
         for arg, val in kwargs.items():
             self.assertEqual(OP.mock_calls[-2][2][arg], val)
+        self.assertEqual(OP.mock_calls[-1][2]['if_etag_not_match'], '*')
+        self.assertEqual(OP.mock_calls[-1][2]['etag'], etag)
 
     def test_get_object_info(self):
         FR.headers = object_info