Add YAML include support for modular configuration

Author: 6C656C65

config.yaml.example

@@ -1,3 +1,6 @@
+#include:
+#  - config/example.yaml
+
 server:
   host: "0.0.0.0"
   port: 8080

pyproxy/utils/args.py

@@ -95,6 +95,18 @@ def parse_args() -> argparse.Namespace:
     return parser.parse_args()
 
 
+def deep_merge_dicts(base: dict[str, Any], new: dict[str, Any]) -> dict[str, Any]:
+    """
+    Merge two dictionaries recursively.
+    """
+    for key, value in new.items():
+        if isinstance(value, dict) and isinstance(base.get(key), dict):
+            base[key] = deep_merge_dicts(base[key], value)
+        else:
+            base[key] = value
+    return base
+
+
 def load_config(config_path: str) -> dict[str, Any]:
     """
     Loads the YAML configuration file and returns it as a dictionary.
@@ -106,9 +118,19 @@ def load_config(config_path: str) -> dict[str, Any]:
         dict[str, Any]: Parsed YAML configuration
     """
     with open(config_path, "r", encoding="utf-8") as f:
-        config = yaml.safe_load(f)
-    if not isinstance(config, dict):
-        raise ValueError("Invalid YAML configuration format.")
+        config = yaml.safe_load(f) or {}
+
+    includes = config.pop("include", [])
+    if not isinstance(includes, list):
+        raise ValueError("'include' must be a list of file paths.")
+
+    for inc_path in includes:
+        inc_abs_path = os.path.join(os.path.dirname(config_path), inc_path)
+        if os.path.exists(inc_abs_path):
+            with open(inc_abs_path, "r", encoding="utf-8") as f:
+                sub_config = yaml.safe_load(f) or {}
+            config = deep_merge_dicts(config, sub_config)
+
     return config