Refactoring merge Method into a New Class & Adding Unit Tests (#137)

kvmd/apps/__init__.py

@@ -53,6 +53,7 @@ from ..yamlconf import Option
 from ..yamlconf import build_raw_from_options
 from ..yamlconf.dumper import make_config_dump
 from ..yamlconf.loader import load_yaml_file
+from ..yamlconf.merger import yaml_merge
 
 from ..validators.basic import valid_stripped_string
 from ..validators.basic import valid_stripped_string_not_empty
@@ -177,8 +178,8 @@ def _init_config(config_path: str, override_options: list[str], **load_flags: bo
 
     scheme = _get_config_scheme()
     try:
-        tools.merge(raw_config, (raw_config.pop("override", {}) or {}))
-        tools.merge(raw_config, build_raw_from_options(override_options))
+        yaml_merge(raw_config, (raw_config.pop("override", {}) or {}))
+        yaml_merge(raw_config, build_raw_from_options(override_options), "raw command line options")
         _patch_raw(raw_config)
         config = make_config(raw_config, scheme)
 

kvmd/tools.py

@@ -45,15 +45,6 @@ def efmt(err: Exception) -> str:
 
 
 # =====
-def merge(dest: dict, src: dict) -> None:
-    for key in src:
-        if key in dest:
-            if isinstance(dest[key], dict) and isinstance(src[key], dict):
-                merge(dest[key], src[key])
-                continue
-        dest[key] = src[key]
-
-
 def rget(dct: dict, *keys: Hashable) -> dict:
     result = functools.reduce((lambda nxt, key: nxt.get(key, {})), keys, dct)
     if not isinstance(result, dict):

kvmd/yamlconf/loader.py

@@ -22,6 +22,8 @@
 
 import os
 
+from .. import tools
+
 from typing import IO
 from typing import Any
 
@@ -30,7 +32,7 @@ import yaml.nodes
 import yaml.resolver
 import yaml.constructor
 
-from .. import tools
+from .merger import yaml_merge
 
 
 # =====
@@ -70,9 +72,9 @@ class _YamlLoader(yaml.SafeLoader):
                 for child in sorted(os.listdir(inc_path)):
                     child_path = os.path.join(inc_path, child)
                     if os.path.isfile(child_path) or os.path.islink(child_path):
-                        tools.merge(tree, (load_yaml_file(child_path) or {}))
+                        yaml_merge(tree, (load_yaml_file(child_path) or {}), child_path)
             else:  # Try file
-                tools.merge(tree, (load_yaml_file(inc_path) or {}))
+                yaml_merge(tree, (load_yaml_file(inc_path) or {}), inc_path)
         return tree
 
 

kvmd/yamlconf/merger.py

@@ -0,0 +1,48 @@
+# ========================================================================== #
+#                                                                            #
+#    KVMD - The main PiKVM daemon.                                           #
+#                                                                            #
+#    Copyright (C) 2018-2022  Maxim Devaev <mdevaev@gmail.com>               #
+#                                                                            #
+#    This program is free software: you can redistribute it and/or modify    #
+#    it under the terms of the GNU General Public License as published by    #
+#    the Free Software Foundation, either version 3 of the License, or       #
+#    (at your option) any later version.                                     #
+#                                                                            #
+#    This program is distributed in the hope that it will be useful,         #
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of          #
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           #
+#    GNU General Public License for more details.                            #
+#                                                                            #
+#    You should have received a copy of the GNU General Public License       #
+#    along with this program.  If not, see <https://www.gnu.org/licenses/>.  #
+#                                                                            #
+# ========================================================================== #
+
+from typing import Optional
+
+
+# =====
+def _merge(dest: dict, src: dict) -> None:
+    for key in src:
+        if key in dest:
+            if isinstance(dest[key], dict) and isinstance(src[key], dict):
+                _merge(dest[key], src[key])
+                continue
+        dest[key] = src[key]
+
+
+def yaml_merge(dest: dict, src: dict, source_name: Optional[str]=None) -> None:
+    """ Merges the source dictionary into the destination dictionary. """
+
+    # Checking if destination is None
+    if dest is None:
+        # We can't merge into a None
+        raise ValueError(f"Could not merge {source_name} into None. The destination cannot be None")
+
+    # Checking if source is None or empty
+    if src is None:
+        # If src is None or empty, there's nothing to merge
+        return
+
+    _merge(dest, src)