feat: Add config loading (#11)

* build: Update dependencies and ruff settings

* feat: Add io functions for reading config files

* feat: Add function for loading a config

* test: Add test cases for io functions

* feat: Add safe loading of config

* feat Add test cases for config module

* docs: Add section on config files to README

* chore: Add ruff cache to .gitignore

* refactor: Rename get and set function in config.py

* style: Use pattern matching instead of if-statements

* docs: Update package docstring

* refactor: Remove file-existence check

* fix: Fix pyright issues

.gitignore

@@ -163,4 +163,7 @@ cython_debug/
 #.idea/
 
 # Test data
-!tests/data/.env
+!tests/data/.env
+
+# Ruff
+.ruff_cache

docs/README.md

@@ -33,6 +33,30 @@ from pit import viper
 env = viper.auto_env()
 ```
 
+### Config Files
+
+Config files are another config source for `pit-viper`. The package supports
+loading, accessing, and setting defaults for a config. Supported file formats
+are JSON, TOML, and YAML.
+
+```python
+from pathlib import Path
+from pit import viper
+
+MY_CONFIG_DIR = Path() / "config"
+
+viper.set_config_path(MY_CONFIG_DIR)
+viper.set_config_name("my_config")
+viper.set_config_type("toml")
+
+viper.set("foo", "default-value")
+
+viper.load_config()
+
+bar = viper.get("foo")
+nested_parameter = viper.get("my.nested.parameter")
+```
+
 ## Development
 
 We use [Poetry](https://github.com/python-poetry/poetry) for packaging and

pyproject.toml

@@ -26,9 +26,12 @@ packages = [{include = "pit", from = "src"}]
 
 [tool.poetry.dependencies]
 python = "^3.11"
+pyyaml = "^6.0.1"
 
 [tool.poetry.group.dev.dependencies]
 pytest = "^7.4.2"
+black = "^23.10.1"
+ruff = "^0.1.3"
 
 [build-system]
 requires = ["poetry-core"]
@@ -47,6 +50,7 @@ pythonVersion = "3.11"
 
 [tool.ruff]
 select = ["ALL"]
+ignore = ["ANN401"]  # Use of typing.Any  
 fixable = ["ALL"]
 fix = true
 line-length = 79

src/pit/viper/__init__.py

@@ -1,17 +1,40 @@
 """Pit-viper offers configuration management capabilities.
 
-This package currently provides one main function, `auto_env`,
-which reads a `.env` file and sets the corresponding environment
-variables in the current process. This can be useful for configuring
-applications or scripts that rely on environment variables.
+This package supports accessing parameters from environment variables,
+and configuration files.
 
 Usage:
     >>> from pit import viper
+    >>> from pathlib import Path
+    >>>
     >>> viper.auto_env()
+    >>>
+    >>> viper.set_config_path(Path() / "config")
+    >>> viper.set_config_name("my_config")
+    >>> viper.set_config_type("toml")
+    >>> viper.set("foo", "default-value")
+    >>>
+    >>> viper.load_config()
+    >>> foo = viper.get("foo")
 
-For more information, see the documentation for the `auto_env`
-function.
+For more information, see the https://github.com/leoschleier/pit-viper.
 """
+from pit.viper.config import get_conf as get
+from pit.viper.config import (
+    load_config,
+    set_config_name,
+    set_config_path,
+    set_config_type,
+)
+from pit.viper.config import set_conf as set  # noqa: A001
 from pit.viper.env import auto_env
 
-__all__ = ["auto_env"]
+__all__ = [
+    "auto_env",
+    "get",
+    "load_config",
+    "set",
+    "set_config_name",
+    "set_config_path",
+    "set_config_type",
+]

src/pit/viper/_io.py

@@ -0,0 +1,94 @@
+"""Internal IO functions for viper."""
+import json
+import tomllib
+from pathlib import Path
+from typing import Any
+
+import yaml
+
+
+def read_config(path: Path) -> dict[str, Any]:
+    """Read a config file.
+
+    This function supports configs from JSON, TOML, and YAML files.
+
+    Parameters
+    ----------
+    path : Path
+       Path to the config file.
+
+    Returns
+    -------
+    dict[str, Any]
+        Config
+
+    Raises
+    ------
+    ValueError
+        Raised if the config file extension is not supported.
+    """
+    file_extension = path.suffix if path.suffix else path.name
+
+    match file_extension:
+        case ".json":
+            return _read_json(path)
+        case ".toml":
+            return _read_toml(path)
+        case ".yml" | ".yaml":
+            return _read_yaml(path)
+        case _:
+            msg = f"Config file extension {file_extension} not supported."
+            raise ValueError(msg)
+
+
+
+
+def _read_json(path: Path) -> dict[str, Any]:
+    """Read a JSON file.
+
+    Parameters
+    ----------
+    path : Path
+        Path to the JSON file.
+
+    Returns
+    -------
+    dict[str, Any]
+        JSON file contents.
+    """
+    with path.open("rb") as stream:
+        return json.load(stream)
+
+
+def _read_toml(path: Path) -> dict[str, Any]:
+    """Read a TOML file.
+
+    Parameters
+    ----------
+    path : Path
+        Path to the TOML file.
+
+    Returns
+    -------
+    dict[str, Any]
+        TOML file contents.
+    """
+    with path.open("rb") as stream:
+        return tomllib.load(stream)
+
+
+def _read_yaml(path: Path) -> dict[str, Any]:
+    """Read a YAML file.
+
+    Parameters
+    ----------
+    path : Path
+        Path to the YAML file.
+
+    Returns
+    -------
+    dict[str, Any]
+        YAML file contents.
+    """
+    with path.open("rb") as stream:
+        return yaml.safe_load(stream)

src/pit/viper/config.py

@@ -0,0 +1,135 @@
+"""Load config from file."""
+from pathlib import Path
+from typing import Any
+
+from pit.viper import _io
+
+_config_path: Path | None = None
+_config_name: str = ""
+_config_type: str = ""
+_config: dict[str, Any] = {}
+
+
+def set_config_name(name: str) -> None:
+    """Set the config name.
+
+    Parameters
+    ----------
+    name : str
+        Name of the config file.
+    """
+    global _config_name  # noqa: PLW0603
+    _config_name = name
+
+
+def set_config_path(path: Path) -> None:
+    """Set the config path.
+
+    Parameters
+    ----------
+    path : Path
+        Path to the config file or the directory containing the config
+        file.
+    """
+    global _config_path  # noqa: PLW0603
+    _config_path = path
+
+
+def set_config_type(type_: str) -> None:
+    """Set the config type.
+
+    Supported config formats: json, toml, yaml, yml.
+
+    Parameters
+    ----------
+    type_ : str
+        Config format.
+    """
+    global _config_type  # noqa: PLW0603
+    _config_type = type_.lower()
+
+
+def get_conf(key: str, default: Any = None) -> Any:
+    """Get a value from the config.
+
+    Parameters
+    ----------
+    key : str
+        Key to get the value for.
+    default : Any, optional
+        Default value to return if the key is not found, by default None
+
+    Returns
+    -------
+    Any
+        Value for the key.
+    """
+    keys = key.split(".")
+    value = _config
+
+    for k in keys:
+        if isinstance(value, dict):
+            value = value.get(k, default)
+
+    return value
+
+
+def set_conf(key: str, value: Any) -> None:
+    """Set a value in the config.
+
+    Parameters
+    ----------
+    key : str
+        Key to set the value for.
+    value : Any
+        Value to set.
+    """
+    keys = key.split(".")
+    config = _config
+
+    for k in keys[:-1]:
+        if isinstance(config, dict):
+            config = config.setdefault(k, {})
+
+    config[keys[-1]] = value
+
+
+def load_config() -> None:
+    """Load the config from the config file.
+
+    Raises
+    ------
+    FileNotFoundError
+        Raised if the config path is not set or the path does not exist.
+    """
+    if not _config_path:
+        msg = "Config path not set."
+        raise FileNotFoundError(msg)
+
+    config_file = (
+        f"{_config_name}.{_config_type}" if _config_type else _config_name
+    )
+    config_path = _config_path / config_file
+
+    config = _io.read_config(config_path)
+    for key, value in config.items():
+        _safe_set(key, value)
+
+
+def _safe_set(key: str, value: Any) -> None:
+    """Set a value in the config without overwriting nested defaults.
+
+    Parameters
+    ----------
+    key : str
+        Key to set the value for.
+    value : Any
+        Value to set.
+    """
+    if isinstance(value, dict):
+        for k, v in value.items():  # pyright: ignore [reportUnknownVariableType]
+            _safe_set(f"{key}.{k}", v)
+    else:
+        set_conf(key, value)
+
+

tests/data/config/config.json

@@ -0,0 +1,11 @@
+{
+    "foo": "bar",
+    "test": {
+        "nested": {
+            "a": 0,
+            "b": 1.1,
+            "c": true,
+            "d": "test-string"
+        }
+    }
+}

tests/data/config/config.toml

@@ -0,0 +1,8 @@
+foo = "bar"
+
+[test]
+[test.nested]
+a = 0
+b = 1.1
+c = true
+d = "test-string"

tests/data/config/config.yaml

@@ -0,0 +1,8 @@
+foo: bar
+
+test:
+  nested:
+    a: 0
+    b: 1.1
+    c: true
+    d: test-string