A OpenFeature Python Environment Variable Provider

This provider loads flag values from environment variables. If a flag with some key is evaluated when no env var named after this key exists, it will throw a FlagNotFoundError. Otherwise it will attempt to parse the string value of the env var to the appropriate type (str,int,float, or object). Errors during this parsing are forwarded to the user.

Installation

pip install openfeature-provider-env-var

Usage

Create a new instance of the EnvVarProvider:

provider = EnvVarProvider()

Configure the OpenFeature API to use the EnvVarProvider and retrieve the client:

from openfeature import api
from openfeature.contrib.provider.envvar import EnvVarProvider

api.set_provider(EnvVarProvider())
client = api.get_client()
result = client.get_boolean_value("<your feature flag key>", True)

The EnvVarProvider will attempt to read values from the present environment variables. If no values is present for a flag key, it will throw a FlagNotFoundError. Otherwise, it will attempt to parse the value associated with the key to the requested type (e.g. float in the case of provider.resolve_float_details(key, 0.0, None)) and forward any error that is raised during parsing to the user. Note that any such errors will be caught by the OpenFeature API and translated into appropriate error codes.

Build setup

This provider uses uv as build tool.

Building

uv build

Executing tests

uv run pytest

pre commit hooks

Install the pre commit hooks that ensure proper formatting:

uvx pre-commit install

License

Apache 2.0 - See LICENSE for more information.