feature_flags

simple_module_feature_flags

Feature flags for simple_module apps. Global flags with per-tenant overrides, a tiny consumer API, and no external service to run.

Install

pip install simple_module_feature_flags

What it provides

• Flags are declared via the framework register_feature_flags hook (FeatureFlagDefinition(name, default_enabled=...)); the module persists only overrides in the feature_flags_override SQLModel table (scoped by scope / scope_id).
• FeatureFlagRegistry.is_enabled("flag.name", tenant_id=...) consumer API (resolution order: tenant override > system override > declared default).
• Admin UI at /feature_flags — toggle flags, add per-scope overrides.
• The registry is an in-memory cache hydrated from the DB so checking a flag on every request is cheap.

Usage

Declare a flag in your module:

from simple_module_core.feature_flags import FeatureFlagDefinition, FeatureFlagRegistry


class OrdersModule(ModuleBase):
    def register_feature_flags(self, registry: FeatureFlagRegistry) -> None:
        registry.add(FeatureFlagDefinition(name="orders.new_pricing_engine", default_enabled=False))

Gate a route using the registry dependency:

from fastapi import APIRouter, HTTPException

from feature_flags.deps import FeatureFlagRegistryDep  # type: ignore[import-not-found]

router = APIRouter()


@router.get("/new-feature")
async def new_feature(flags: FeatureFlagRegistryDep):
    if not flags.is_enabled("orders.new_pricing_engine"):
        raise HTTPException(404)
    return {"rolled_out": True}

Overrides (system or per-tenant) are managed through the admin UI at /feature_flags.

Depends on

• simple_module_core, simple_module_db, simple_module_hosting

License

MIT — see LICENSE.