feat: dotenv (#15)

* deps: add python-dotenv

* feat: dotenv support

docs/examples/simple_yaml.md

@@ -51,4 +51,4 @@ $ python simple_app.py --config config.yml --opt1 people
 people nothing stuff
 ```
 
-> **Note**: this package also provides `json_conf_callback` and `toml_conf_callback` for those file formats.
+> **Note**: this package also provides `json_conf_callback`, `toml_conf_callback`, and `dotenv_conf_callback` for those file formats.

docs/install.md

@@ -15,5 +15,7 @@ $ pip install typer-config[yaml] # includes pyyaml
 
 $ pip install typer-config[toml] # includes toml
 
+$ pip install typer-config[python-dotenv] # includes python-dotenv
+
 $ pip install typer-config[all] # includes all optional dependencies
 ```

pyproject.toml

@@ -17,6 +17,7 @@ keywords = [
         "yaml",
         "toml",
         "json",
+        "dotenv",
         "cli"
     ]
 classifiers = [
@@ -44,11 +45,13 @@ python = "^3.8"
 typer = "^0"
 toml = {version = "^0.10.2", optional = true}
 pyyaml = {version = "^6.0", optional = true}
+python-dotenv = {version = "*", optional = true}
 
 [tool.poetry.extras]
+python-dotenv = ["python-dotenv"]
 toml = ["toml"]
 yaml = ["pyyaml"]
-all = ["toml", "pyyaml"]
+all = ["toml", "pyyaml", "python-dotenv"]
 
 [tool.poetry.group.dev.dependencies]
 ruff = "^0.0.263"

tests/config.env

@@ -0,0 +1,3 @@
+arg1=stuff
+opt1="things"
+opt2='nothing'

tests/test_example.py

@@ -40,6 +40,7 @@ def test_simple_example(simple_app):
         (str(HERE.joinpath("config.yml")), typer_config.yaml_conf_callback),
         (str(HERE.joinpath("config.json")), typer_config.json_conf_callback),
         (str(HERE.joinpath("config.toml")), typer_config.toml_conf_callback),
+        (str(HERE.joinpath("config.env")), typer_config.dotenv_conf_callback),
     ]
 
     # Test all the combinations of formats and extra parameters
@@ -68,7 +69,7 @@ def test_simple_example(simple_app):
         assert (
             result.exit_code != 0
         ), f"Should have failed for {conf}\n\n{result.stdout}"
-        assert "No such file" in result.stdout
+        assert "No such file" in result.stdout, f"Wrong error message for {conf}"
 
 
 def test_pyproject_example(simple_app):

typer_config/__init__.py

@@ -5,7 +5,7 @@
 from typer import BadParameter, CallbackParam, Context
 
 from .__typing import ConfigLoader, ConfigParameterCallback, TyperParameterValue
-from .loaders import json_loader, toml_loader, yaml_loader
+from .loaders import dotenv_loader, json_loader, toml_loader, yaml_loader
 
 
 def conf_callback_factory(loader: ConfigLoader) -> ConfigParameterCallback:
@@ -127,3 +127,26 @@ def _callback(
 typer.BadParameter
     bad parameter value
 """
+
+dotenv_conf_callback: ConfigParameterCallback = conf_callback_factory(dotenv_loader)
+"""Dotenv configuration callback for a typer parameter.
+
+Parameters
+----------
+ctx : typer.Context
+    typer context (automatically passed)
+param : typer.CallbackParam
+    typer callback parameter (automatically passed)
+param_value : TyperParameterValue
+    parameter value passed to typer (automatically passed)
+
+Returns
+-------
+TyperParameterValue
+    must return back the given parameter
+
+Raises
+------
+typer.BadParameter
+    bad parameter value
+"""

typer_config/loaders.py

@@ -17,6 +17,7 @@
 USING_TOMLLIB = False
 TOML_MISSING = True
 YAML_MISSING = True
+DOTENV_MISSING = True
 
 
 if sys.version_info >= (3, 11):  # pragma: no cover
@@ -42,6 +43,13 @@
 except ImportError:  # pragma: no cover
     pass
 
+try:  # pragma: no cover
+    import dotenv
+
+    DOTENV_MISSING = False
+except ImportError:  # pragma: no cover
+    pass
+
 
 def subpath_loader(
     loader: ConfigLoader, dictpath: ConfigDictAccessorPath
@@ -173,3 +181,28 @@ def toml_loader(param_value: TyperParameterValue) -> ConfigDict:
             conf = toml.load(_file)  # type: ignore
 
     return conf
+
+
+def dotenv_loader(param_value: TyperParameterValue) -> ConfigDict:
+    """Dotenv file loader
+
+    Parameters
+    ----------
+    param_value : TyperParameterValue
+        path of YAML file
+
+    Returns
+    -------
+    ConfigDict
+        dictionary loaded from file
+    """
+
+    if DOTENV_MISSING:  # pragma: no cover
+        raise ModuleNotFoundError("Please install the python-dotenv library.")
+
+    with open(param_value, "r", encoding="utf-8") as _file:
+        # NOTE: I'm using a stream here so that the loader
+        # will raise an exception when the file doesn't exist.
+        conf: ConfigDict = dotenv.dotenv_values(stream=_file)
+
+    return conf