openfeature-sdk 0.4.0

Standardizing Feature Flagging for Everyone

OpenFeature Python SDK

OpenFeature is an open specification that provides a vendor-agnostic, community-driven API for feature flagging that works with your favorite feature flag management tool.

🚀 Quick start

Requirements

• Python 3.8+

Install

Pip install

pip install openfeature-sdk==0.4.0

requirements.txt

openfeature-sdk==0.4.0

pip install -r requirements.txt

Usage

from openfeature import api
from openfeature.provider.in_memory_provider import InMemoryFlag, InMemoryProvider

# flags defined in memory
my_flags = {
  "v2_enabled": InMemoryFlag("on", {"on": True, "off": False})
}

# configure a provider
api.set_provider(InMemoryProvider(my_flags))

# create a client
client = api.get_client()

# get a bool flag value
flag_value = client.get_boolean_value("v2_enabled", False)
print("Value: " + str(flag_value))

🌟 Features

Status	Features	Description
✅	Providers	Integrate with a commercial, open source, or in-house feature management tool.
✅	Targeting	Contextually-aware flag evaluation using evaluation context.
✅	Hooks	Add functionality to various stages of the flag evaluation life-cycle.
❌	Logging	Integrate with popular logging packages.
❌	Named clients	Utilize multiple providers in a single application.
❌	Eventing	React to state changes in the provider or flag management system.
✅	Shutdown	Gracefully clean up a provider during application shutdown.
✅	Extending	Extend OpenFeature with custom providers and hooks.

_{Implemented: ✅ | In-progress: ⚠️ | Not implemented yet: ❌}

Providers

Providers are an abstraction between a flag management system and the OpenFeature SDK. Look here for a complete list of available providers. If the provider you're looking for hasn't been created yet, see the develop a provider section to learn how to build it yourself.

Once you've added a provider as a dependency, it can be registered with OpenFeature like this:

from openfeature import api
from openfeature.provider.no_op_provider import NoOpProvider

api.set_provider(NoOpProvider())
open_feature_client = api.get_client()

Targeting

Sometimes, the value of a flag must consider some dynamic criteria about the application or user, such as the user's location, IP, email address, or the server's location. In OpenFeature, we refer to this as targeting. If the flag management system you're using supports targeting, you can provide the input data using the evaluation context.

from openfeature.api import (
    get_client,
    get_provider,
    set_provider,
    get_evaluation_context,
    set_evaluation_context,
)

global_context = EvaluationContext(
    targeting_key="targeting_key1", attributes={"application": "value1"}
)
request_context = EvaluationContext(
    targeting_key="targeting_key2", attributes={"email": request.form['email']}
)

## set global context
set_evaluation_context(global_context)

# merge second context
client = get_client(name="No-op Provider")
client.get_string_value("email", "fallback", request_context)

Hooks

Hooks allow for custom logic to be added at well-defined points of the flag evaluation life-cycle. Look here for a complete list of available hooks. If the hook you're looking for hasn't been created yet, see the develop a hook section to learn how to build it yourself.

Once you've added a hook as a dependency, it can be registered at the global, client, or flag invocation level.

from openfeature.api import add_hooks
from openfeature.flag_evaluation import FlagEvaluationOptions

# set global hooks at the API-level
add_hooks([MyHook()])

# or configure them in the client
client = OpenFeatureClient()
client.add_hooks([MyHook()])

# or at the invocation-level
options = FlagEvaluationOptions(hooks=[MyHook()])
client.get_boolean_flag("my-flag", False, flag_evaluation_options=options)

Logging

Logging customization is not yet available in the Python SDK.

Named clients

Named clients are not yet available in the Python SDK. Progress on this feature can be tracked here.

Eventing

Events are not yet available in the Python SDK. Progress on this feature can be tracked here.

Shutdown

A shutdown method is not yet available in the Python SDK. Progress on this feature can be tracked here.

Extending

Develop a provider

To develop a provider, you need to create a new project and include the OpenFeature SDK as a dependency. This can be a new repository or included in the existing contrib repository available under the OpenFeature organization. You’ll then need to write the provider by implementing the AbstractProvider class exported by the OpenFeature SDK.

from typing import List, Optional

from openfeature.evaluation_context import EvaluationContext
from openfeature.flag_evaluation import FlagResolutionDetails
from openfeature.provider.provider import AbstractProvider

class MyProvider(AbstractProvider):
    def get_metadata(self) -> Metadata:
        ...

    def get_provider_hooks(self) -> List[Hook]:
        return []

    def resolve_boolean_details(
        self,
        flag_key: str,
        default_value: bool,
        evaluation_context: Optional[EvaluationContext] = None,
    ) -> FlagResolutionDetails[bool]:
        ...

    def resolve_string_details(
        self,
        flag_key: str,
        default_value: str,
        evaluation_context: Optional[EvaluationContext] = None,
    ) -> FlagResolutionDetails[str]:
        ...

    def resolve_integer_details(
        self,
        flag_key: str,
        default_value: int,
        evaluation_context: Optional[EvaluationContext] = None,
    ) -> FlagResolutionDetails[int]:
        ...

    def resolve_float_details(
        self,
        flag_key: str,
        default_value: float,
        evaluation_context: Optional[EvaluationContext] = None,
    ) -> FlagResolutionDetails[float]:
        ...

    def resolve_object_details(
        self,
        flag_key: str,
        default_value: Union[dict, list],
        evaluation_context: Optional[EvaluationContext] = None,
    ) -> FlagResolutionDetails[Union[dict, list]]:
        ...

Built a new provider? Let us know so we can add it to the docs!

Develop a hook

To develop a hook, you need to create a new project and include the OpenFeature SDK as a dependency. This can be a new repository or included in the existing contrib repository available under the OpenFeature organization. Implement your own hook by creating a hook that inherits from the Hook class. Any of the evaluation life-cycle stages (before/after/error/finally_after) can be override to add the desired business logic.

from openfeature.hook import Hook

class MyHook(Hook):
    def after(self, hook_context: HookContext, details: FlagEvaluationDetails, hints: dict):
        print("This runs after the flag has been evaluated")

Built a new hook? Let us know so we can add it to the docs!

⭐️ Support the project

• Give this repo a ⭐️!
• Follow us on social media:
  • Twitter: @openfeature
  • LinkedIn: OpenFeature
• Join us on Slack
• For more, check out our community page

🤝 Contributing

Interested in contributing? Great, we'd love your help! To get started, take a look at the CONTRIBUTING guide.

Thanks to everyone who has already contributed

Made with contrib.rocks.