feat(node): add ability to load changes from yaml and json

README.md

@@ -116,6 +116,33 @@ assert cfg.NAME == "Hello World!"
 assert cfg.DICT.FOO == "BAR"
 ```
 
+1. You can also load from YAML or JSON:
+
+```yaml
+# my_changes.yaml
+DICT:
+  FOO: BAR
+```
+
+```json
+# my_changes.json
+{
+  "DICT": {
+    "INT": 2
+  }
+}
+```
+
+```python
+# main.py
+from project.config import schema
+
+cfg = schema.load_updates_from_file("my_changes.yaml")
+assert cfg.DICT.FOO == "BAR"
+cfg = schema.load_updates_from_file("my_changes.json")
+assert cfg.DICT.INT == 2
+```
+
 ## Development
 
 - Install dev dependencies: `pip install -e ".[dev]"`

pycs/node.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import inspect
+import json
 import logging
 import warnings
 from collections import UserDict
@@ -175,6 +176,28 @@ def load(cfg_path: Union[Path, str]) -> CfgNode:
         cfg.propagate_changes()
         return cfg
 
+    def load_updates_from_file(self, updates_path: Union[Path, str]) -> CfgNode:
+        updates_path = Path(updates_path)
+        suffix = updates_path.suffix
+        with updates_path.open() as f:
+            if suffix == ".py":
+                module = import_module(updates_path)
+                updates: MutableMapping = module.cfg
+            elif suffix == ".json":
+                updates = json.load(f)
+            elif suffix == ".yaml":
+                updates = yaml.safe_load(f)
+            else:
+                raise ValueError(f"Can't load changes from filetype with suffix '{suffix}'")
+        cfg = self.init_cfg()
+        cfg.update(updates)
+
+        if hasattr(cfg, "NAME"):
+            cfg.NAME = cfg.NAME or _cfg_path_to_name(updates_path, cfg._root_name)  # noqa: SLF001 Same class
+
+        cfg.propagate_changes()
+        return cfg
+
     @staticmethod
     def validate_required(cfg: CfgNode) -> None:
         if cfg.leaf_spec is not None and cfg.leaf_spec.required and len(cfg) == 0:

tests/data/node/json_cfg.json

@@ -0,0 +1,9 @@
+{
+    "BOOL": true,
+    "INT": 1,
+    "FLOAT": 1.1,
+    "STR": "json",
+    "NESTED": {
+        "FOO": "zoo"
+    }
+}

tests/data/node/python_cfg.py

@@ -0,0 +1,9 @@
+from pycs import CN
+
+cfg = CN()
+cfg.BOOL = True
+cfg.INT = 1
+cfg.FLOAT = 1.1
+cfg.STR = "py"
+cfg.NESTED = CN()
+cfg.NESTED.FOO = "zoo"

tests/data/node/yaml_cfg.yaml

@@ -0,0 +1,8 @@
+---
+BOOL: true
+INT: 1
+FLOAT: 1.1
+STR: yaml
+
+NESTED:
+  FOO: zoo

tests/test_node.py

@@ -1,10 +1,14 @@
 from __future__ import annotations
 
+from pathlib import Path
+
 import pytest
 
 from pycs import CL, CN
 from pycs.errors import MissingRequiredError, NodeReassignmentError, SchemaFrozenError, TypeMismatchError
 
+DATA_DIR = Path(__file__).parent / "data" / "node"
+
 
 class Quux:
     def __str__(self):
@@ -299,3 +303,30 @@ def test_update_both(self, cfg: CN):
         cfg.update({"FOO": "both"}, new="bar")
         assert cfg.FOO == "both"
         assert cfg.new == "bar"
+
+
+@pytest.mark.parametrize("filename", ["json_cfg.json", "yaml_cfg.yaml", "python_cfg.py"])
+def test_load_updates_from_file(filename):
+    schema = CN()
+    schema.NAME = ""
+    schema.BOOL = False
+    schema.INT = 0
+    schema.FLOAT = 0.0
+    schema.STR = ""
+    schema.NESTED = CN()
+    schema.NESTED.FOO = "bar"
+    schema.DEFAULT = "default"
+
+    cfg_path = DATA_DIR / filename
+    cfg = schema.load_updates_from_file(cfg_path)
+
+    assert cfg.NAME == cfg_path.stem  # noqa: SIM300
+    assert cfg.BOOL
+    assert cfg.INT == 1
+    assert cfg.FLOAT == 1.1
+    assert cfg.STR == cfg_path.suffix[1:]  # noqa: SIM300
+    assert cfg.NESTED.FOO == "zoo"
+    assert cfg.DEFAULT == "default"
+
+    # Test that original was not modified
+    assert not schema.BOOL