change name of object when no bucket set

input dataxx/itemname gets uploaded to dataxx bucket as itemname (makes 
it possible to mimic old preprocessor this way in case no bucket set)
motivation in this commit is to AVOID data duplication in new bucket and 
dataxx buckets with possible reprocessing campaing

preprocessor/preprocessor/transfer/swift.py

@@ -39,19 +39,20 @@ class Base:
             "os_user_domain_name": self.user_domain_name,
         })
 
+    def validate_container(self, remote_dir):
+        if self.container:
+            # container was specified, use it
+            return self.container, remote_dir
+        # container needs to be extracted from path
+        # paths needs to be updated
+        return remote_dir.partition('/')[0], remote_dir.partition('/')[2]
+
 
 class Downloader(Base):
     """ Downloader for OpenStack swift object storages
     """
     def download(self, remote_path: os.PathLike, local_path: os.PathLike) -> os.PathLike:
-        if self.container:
-            # container was specified, use it
-            container = self.container
-        else:
-            # container needs to be extracted from path
-            # paths needs to be updated
-            container = remote_path.partition('/')[0]
-            remote_path = remote_path.partition('/')[2]
+        container, remote_path = self.validate_container(remote_path)
         target_filename = os.path.join(local_path, os.path.basename(remote_path))
         with self.get_service() as swift:
             results = swift.download(
@@ -74,6 +75,7 @@ class Uploader(Base):
     """
     def upload(self, local_path: Union[os.PathLike, List[os.PathLike]], remote_dir: os.PathLike) -> List[os.PathLike]:
         paths = local_path if isinstance(local_path, List) else [local_path]
+        container, remote_dir = self.validate_container(remote_dir)
         remote_paths = [
             os.path.join(
                 remote_dir,
@@ -99,7 +101,6 @@ class Uploader(Base):
 
         with self.get_service() as swift:
             # use container or first part of path
-            container = self.container or remote_dir.partition('/')[0]
             results = swift.upload(container=container, objects=objects, options=options)
 
             for result in results:
@@ -123,8 +124,7 @@ class Uploader(Base):
 
     def product_exists(self, remote_dir: os.PathLike) -> bool:
         with self.get_service() as swift:
-            # use container or first part of path
-            container = self.container or remote_dir.partition('/')[0]
+            container, remote_dir = self.validate_container(remote_dir)
             list_parts_gen = swift.list(
                 container=container, options={"prefix": remote_dir},
             )