init commit

app/utils/settings.py

@@ -0,0 +1,127 @@
+# 
+# Note the settings file is hardcoded in this class at the top after imports.
+# 
+# To make a new settings section, just add the setting dict to your yaml 
+# and then define the data class below in the config data classes area.
+# 
+# Example use from anywhere - this will always return the same singleton 
+# from settings import get_settings
+# def main():
+#     settings = get_settings()
+#     print(settings.database.host)  # Autocomplete works
+#     print(settings.logging.level)
+
+# if __name__ == "__main__":
+#     main()
+
+import functools
+from pathlib import Path
+from typing import Any, Callable, TypeVar
+from dataclasses import dataclass, fields, is_dataclass, field, MISSING
+
+try:
+    import yaml
+except ModuleNotFoundError:
+    import logging
+    import sys
+
+    logger = logging.getLogger(__file__)
+    msg = (
+        "Required modules are not installed. "
+        "Can not continue with module / application loading.\n"
+        "Install it with: pip install -r requirements"
+    )
+    print(msg, file=sys.stderr)
+    logger.error(msg)
+    exit()
+
+DEFAULT_SETTINGS_FILE = Path.cwd() / "config" /"settings.yaml"
+
+# ---------- CONFIG DATA CLASSES ----------
+@dataclass
+class DatabaseConfig:
+    host: str = "localhost"
+    port: int = 5432
+    username: str = "root"
+    password: str = ""
+
+
+@dataclass
+class AppConfig:
+    name: str = "MyApp"
+    version_major: int = 1
+    version_minor: int = 0
+    production: bool = False
+    enabled: bool = True
+    token_expiry: int = 3600
+
+
+@dataclass
+class Settings:
+    database: DatabaseConfig = field(default_factory=DatabaseConfig)
+    app: AppConfig = field(default_factory=AppConfig)
+
+    @classmethod
+    def from_yaml(cls, path: str | Path) -> "Settings":
+        """Load settings from YAML file into a Settings object."""
+        with open(path, "r", encoding="utf-8") as f:
+            raw: dict[str, Any] = yaml.safe_load(f) or {}
+
+        init_kwargs = {}
+        for f_def in fields(cls):
+            yaml_value = raw.get(f_def.name, None)
+
+            # Determine default value from default_factory or default
+            if f_def.default_factory is not MISSING:
+                default_value = f_def.default_factory()
+            elif f_def.default is not MISSING:
+                default_value = f_def.default
+            else:
+                default_value = None
+
+            # Handle nested dataclasses
+            if is_dataclass(f_def.type):
+                if isinstance(yaml_value, dict):
+                    # Merge YAML values with defaults
+                    merged_data = {fld.name: getattr(default_value, fld.name) for fld in fields(f_def.type)}
+                    merged_data.update(yaml_value)
+                    init_kwargs[f_def.name] = f_def.type(**merged_data)
+                else:
+                    init_kwargs[f_def.name] = default_value
+            else:
+                init_kwargs[f_def.name] = yaml_value if yaml_value is not None else default_value
+
+        return cls(**init_kwargs)
+
+
+# ---------- SINGLETON DECORATOR ----------
+T = TypeVar("T")
+
+def singleton_loader(func: Callable[..., T]) -> Callable[..., T]:
+    """Ensure the function only runs once, returning the cached value."""
+    cache: dict[str, T] = {}
+
+    @functools.wraps(func)
+    def wrapper(*args, **kwargs) -> T:
+        if func.__name__ not in cache:
+            cache[func.__name__] = func(*args, **kwargs)
+        return cache[func.__name__]
+
+    return wrapper
+
+
+@singleton_loader
+def get_settings(config_path: str | Path | None = None) -> Settings:
+    """
+    Returns the singleton Settings instance.
+
+    Args:
+        config_path: Optional path to the YAML config file. If not provided,
+                     defaults to 'config/settings.yaml' in the current working directory.
+    """
+    if config_path is None:
+        config_path = DEFAULT_SETTINGS_FILE
+    else:
+        config_path = Path(config_path)
+
+    return Settings.from_yaml(config_path)