typed-envs 0.2.4

Typed environment variables for python applications.

Typed Envs

typed_envs is used to create specialized EnvironmentVariable objects that behave exactly the same as any other instance of the typ used to create them.

typed_envs is used for: - defining your envs in a readable, user friendly way - enhancing type hints for the returned instances - enhancing repr of the returned instance with extra contextual information

In the example below, some_var can be used just like as any other int object.

import typed_envs
some_var = typed_envs.create_env("SET_WITH_THIS_ENV", int, 10)
>>> isinstance(some_var, int)
True
>>> isinstance(some_var, EnvironmentVariable)
True

There are only 2 differences between some_var and int(10): - some_var will properly type check as an instance of both int and EnvironmentVariable - some_var.__repr__() will include contextual information about the EnvironmentVariable.

>>> some_var
<EnvironmentVariable[name=`SET_WITH_THIS_ENV`, type=int, default_value=10, current_value=10, using_default=True]>
>>> str(some_var)
"10"
>>> some_var + 5
15
>>> 20 / some_var
2

Mypy plugin

Mypy cannot natively model the dynamic subclass created by typed_envs. If you want mypy to treat EnvironmentVariable[T] as having the methods and attributes of both EnvironmentVariable and its underlying T (including for create_env(...) and EnvVarFactory.create_env(...)), enable the plugin:

[mypy]
plugins = typed_envs.mypy_plugin

For pyproject.toml users:

[tool.mypy]
plugins = ["typed_envs.mypy_plugin"]

The plugin synthesizes a mypy-only class that inherits from both EnvironmentVariable and the underlying type, so you can call methods from either side without casts. It also preserves unions, optionals, and common typing constructs like Annotated, TypedDict, and Literal.