Featurevisor OpenFeature provider for Elixir

This Hex package adapts the Featurevisor Elixir SDK to the official OpenFeature Elixir SDK.

Installation

def deps do
  [
    {:featurevisor, "~> 1.2"},
    {:featurevisor_openfeature, "~> 1.2"},
    {:open_feature, "~> 0.1.3"}
  ]
end

The provider is a separate package, so applications that only use featurevisor do not install or compile OpenFeature. The supported upstream SDK is open_feature 0.1.3, the latest stable Hex release. It requires no change to the provider's Elixir 1.15 minimum.

Usage

Create a provider that owns its Featurevisor instance:

provider =
  FeaturevisorOpenFeature.Provider.new(
    featurevisor_options: %{datafile: datafile}
  )

{:ok, provider} = OpenFeature.set_provider(provider)
client = OpenFeature.get_client()

enabled =
  OpenFeature.Client.get_boolean_value(client, "checkout", false,
    context: %{"targetingKey" => "user-123"}
  )

You can also pass an existing Featurevisor instance. The provider borrows it and does not close it:

provider = FeaturevisorOpenFeature.Provider.new(featurevisor: f)

Featurevisor supports several evaluation types through one OpenFeature key:

targeting_key_field, key_separator, variation_key, and global_variable_prefix customize this mapping. The targeting key maps to userId by default. The provider accepts "targetingKey", "targeting_key", and :targeting_key in the OpenFeature context.

The provider implements boolean, string, number, and map resolution. Featurevisor reasons and evaluation metadata are mapped to OpenFeature resolution details. Missing definitions, type mismatches, and invalid datafiles use standard OpenFeature errors. Replacing an invalid datafile with a valid one recovers the provider. If initial registration fails, update the provider's Featurevisor instance with a valid datafile and call OpenFeature.set_provider again. OpenFeature 0.1.3 does not register a provider whose initialisation fails. Once registered, valid updates recover evaluation without registering again, including an unchanged accepted datafile after a rejection.

Calling shutdown/1 releases provider subscriptions. It also closes a Featurevisor instance created by the provider, but never closes a borrowed instance.

The current OpenFeature Elixir SDK does not expose provider tracking. Featurevisor modules and diagnostics continue to run inside the Featurevisor instance.

See the Featurevisor Elixir SDK documentation and the shared OpenFeature provider guide for more details.