feat(hash_checkpoint): create the directory if not exist (#2273)

* feat(hash_checkpoint): create the directory if not exist

* Apply suggestions from code review

Co-authored-by: vfdev <vfdev.5@gmail.com>

* fix: check for checkpoint file existence

* chore: format

Co-authored-by: vfdev <vfdev.5@gmail.com>

Author: ydcjeff

ignite/utils.py

@@ -292,19 +292,24 @@ def hash_checkpoint(checkpoint_path: Union[str, Path], output_dir: Union[str, Pa
 
     Args:
         checkpoint_path: Path to the checkpoint file.
-        output_dir: Output directory to store the hashed checkpoint file.
+        output_dir: Output directory to store the hashed checkpoint file
+            (will be created if not exist).
 
     Returns:
-        Path to the hashed checkpoint file, The 8 digits of SHA256 hash.
+        Path to the hashed checkpoint file, the first 8 digits of SHA256 hash.
 
     .. versionadded:: 0.5.0
     """
 
     if isinstance(checkpoint_path, str):
         checkpoint_path = Path(checkpoint_path)
 
+    if not checkpoint_path.exists():
+        raise FileNotFoundError(f"{checkpoint_path.name} does not exist in {checkpoint_path.parent}.")
+
     if isinstance(output_dir, str):
         output_dir = Path(output_dir)
+        output_dir.mkdir(parents=True, exist_ok=True)
 
     sha_hash = hashlib.sha256(checkpoint_path.read_bytes()).hexdigest()
     old_filename = checkpoint_path.stem

tests/ignite/test_utils.py

@@ -256,3 +256,7 @@ def test_hash_checkpoint(tmp_path):
     model.load_state_dict(torch.load(hash_checkpoint_path), True)
     assert sha_hash[:8] == "b66bff10"
     assert hash_checkpoint_path.name == f"squeezenet1_0-{sha_hash[:8]}.pt"
+
+    # test non-existent checkpoint_path
+    with pytest.raises(FileNotFoundError, match=r"not_found.pt does not exist in *"):
+        hash_checkpoint(f"{tmp_path}/not_found.pt", tmp_path)