Add support for resuming downloads

This commit adds the ability to resume interrupted downloads by adding a new function to the downloader module. The function uses the HTTP Range header to fetch only the remaining part of a file that wasn't downloaded yet.

download-model.py

@@ -27,8 +27,23 @@ parser.add_argument('--output', type=str, default=None, help='The folder where t
 args = parser.parse_args()
 
 def get_file(url, output_folder):
-    r = requests.get(url, stream=True)
-    with open(output_folder / Path(url.rsplit('/', 1)[1]), 'wb') as f:
+    filename = Path(url.rsplit('/', 1)[1])
+    output_path = output_folder / filename
+    if output_path.exists():
+        # Check if the file has already been downloaded completely
+        r = requests.head(url)
+        total_size = int(r.headers.get('content-length', 0))
+        if output_path.stat().st_size == total_size:
+            return
+        # Otherwise, resume the download from where it left off
+        headers = {'Range': f'bytes={output_path.stat().st_size}-'}
+        mode = 'ab'
+    else:
+        headers = {}
+        mode = 'wb'
+
+    r = requests.get(url, stream=True, headers=headers)
+    with open(output_path, mode) as f:
         total_size = int(r.headers.get('content-length', 0))
         block_size = 1024
         with tqdm.tqdm(total=total_size, unit='iB', unit_scale=True, bar_format='{l_bar}{bar}| {n_fmt:6}/{total_fmt:6} {rate_fmt:6}') as t:
@@ -149,7 +164,7 @@ def get_download_links_from_huggingface(model, branch):
     return links, sha256, is_lora
 
 def download_files(file_list, output_folder, num_threads=8):
-    thread_map(lambda url: get_file(url, output_folder), file_list, max_workers=num_threads)
+    thread_map(lambda url: get_file(url, output_folder), file_list, max_workers=num_threads, disable=True)
 
 if __name__ == '__main__':
     model = args.MODEL