Fix Model.download_model_weights() to reuse previously downloaded file

trains/backend_interface/model.py

@@ -376,6 +376,22 @@ class Model(IdObjectBase, AsyncManagerMixin, _StorageUriMixin):
     def tags(self):
         return self.data.system_tags if hasattr(self.data, 'system_tags') else self.data.tags
 
+    @property
+    def task(self):
+        try:
+            return self.data.task
+        except ValueError:
+            # no task is yet specified
+            return None
+
+    @property
+    def uri(self):
+        try:
+            return self.data.uri
+        except ValueError:
+            # no uri is yet specified
+            return None
+
     @property
     def locked(self):
         if self.id is None:
@@ -388,20 +404,19 @@ class Model(IdObjectBase, AsyncManagerMixin, _StorageUriMixin):
         if not uri or not uri.strip():
             return None
 
-        helper = StorageHelper.get(uri)
-        filename = uri.split('/')[-1]
-        ext = '.'.join(filename.split('.')[1:])
-        fd, local_filename = mkstemp(suffix='.'+ext)
-        os.close(fd)
-        local_download = helper.download_to_file(uri, local_path=local_filename, overwrite_existing=True, verbose=True)
-        # if we ended up without any local copy, delete the temp file
-        if local_download != local_filename:
-            try:
-                Path(local_filename).unlink()
-            except Exception:
-                pass
+        # check if we already downloaded the file
+        downloaded_models = [k for k, (i, u) in Model._local_model_to_id_uri.items() if i == self.id and u == uri]
+        for dl_file in downloaded_models:
+            if Path(dl_file).exists():
+                return dl_file
+            # remove non existing model file
+            Model._local_model_to_id_uri.pop(dl_file, None)
+
+        local_download = StorageHelper.get(uri).get_local_copy(uri)
+
         # save local model, so we can later query what was the original one
         Model._local_model_to_id_uri[str(local_download)] = (self.model_id, uri)
+
         return local_download
 
     @property