Very simple implementation of feature flags for FastAPI.

• Minimum configuration required
• No unnecessary dependencies
• Does its job

To install the package from pip, first run:

pip install fastapi-featureflags

A simple example of feature flags:

from fastapi_featureflags import FeatureFlags, feature_flag, feature_enabled

FeatureFlags(conf_from_url="https://pastebin.com/raw/4Ai3j2DC")
print("Enabled Features:", FeatureFlags.get_features())


@feature_flag("web_1")
def web_1_enabled():
    print("Feature Should be enabled: web_1")

web_1_enabled()

if feature_enabled("web_2"):
    print("Feature Should be disabled: web_2")

You can get FF (feature flags) from a File, URL, Dictionary or ENV Variables:

FeatureFlags.load_conf_from_url("https://pastebin.com/raw/4Ai3j2DC")
FeatureFlags.load_conf_from_json("tests/features.json")
FeatureFlags.load_conf_from_dict({"web_1": True, "web_2": False})

FeatureFlags.reload_feature_flags()

There is also a handler that recognizes if the "@feature_flag" wrapper is used and the flag is not registered in the config. This way you can also use FF at runtime. Defaults to False, so it's safer if you forget the feature flag in the code.

Function get_features returns a list of all registered FF
You can enable or disable functions on the fly with enable_feature or enable_feature

When needed you can reload all feature flags with reload_feature_flags, this is useful when you want to read and change features from URL. All unregistered or on-the-fly created FF, that are not in the configuration will be omitted.

For non-production testing, a router is available, so you can see the paths in swagger-ui docs. Use include_in_schema=False when defining the router for public deployments

from fastapi_featureflags import router as ff_router
app.include_router(ff_router, prefix="/ff", tags=["FeatureFlags"])

As an open source project, fastapi-featureflags welcomes contributions of many forms.
Please read and follow our Contributing to fastapi-featureflags

As a contributor, you can help us keep the fastapi-featureflags project open and inclusive.
Please read and follow our Code of Conduct