Make mirror_file fail if file object already exists (#7134)

Author: nadove-ucsc

src/azul/indexer/mirror_service.py

@@ -156,7 +156,7 @@ def mirror_file(self, catalog: CatalogName, file: File):
             self._storage(catalog).put(object_key=self.mirror_object_key(file),
                                        data=file_content,
                                        content_type=file.content_type,
-                                       IfNoneMatch='*')
+                                       exists_okay=False)
             _, digest_type = file.digest()
             hasher = get_resumable_hasher(digest_type)
             hasher.update(file_content)
@@ -204,7 +204,9 @@ def finish_mirroring_file(self,
         Complete a multipart upload begun with :meth:`begin_mirroring_file`.
         """
         upload = self._get_upload(catalog, file, upload_id)
-        self._storage(catalog).complete_multipart_upload(upload, etags)
+        self._storage(catalog).complete_multipart_upload(upload,
+                                                         etags,
+                                                         exists_okay=False)
         self._verify_digest(file, hasher)
         self._check_info(catalog, file)
         self._put_info(catalog, file)