OpenFeature

Load a flag’s evaluated value as config through OpenFeature, the vendor-neutral feature-flag standard - whatever backend (LaunchDarkly, Flagsmith, GO Feature Flag, your own) your application has installed with openfeature.SetProvider is what this provider evaluates against.

Install

go get github.com/xavidop/mamori/providers/openfeature

import _ "github.com/xavidop/mamori/providers/openfeature"

Using the ref

A openfeature:// ref points at one flag key.

openfeature://<flag-key>[#json-key][?type=bool|string|int|float|object]

OpenFeature evaluates a flag by type - there is no single “evaluate and tell me what it is” call. Pin ?type= in production: it costs exactly one evaluation. Without it, the provider tries object, then bool, then string, stopping at the first that is not a type mismatch - useful while exploring, but up to three evaluations per resolve against your vendor. A flag that cannot be evaluated as any of the three reports an error, not not-found: the flag exists, so mamori must not silently fall back to a default:.

Examples

• openfeature://new-checkout?type=bool on a boolean flag resolves to true or false.
• openfeature://max-retries?type=int on a numeric flag resolves to its decimal form.
• openfeature://limits#/upload/maxMB?type=object selects one field out of an object-valued flag.

type Config struct {
	NewCheckout bool   `source:"openfeature://new-checkout?type=bool"`
	MaxUploadMB int    `source:"openfeature://limits#/upload/maxMB?type=object"`
}

Targeting key and identity

Evaluation uses one fixed evaluation context for the whole process: a targeting key (default "mamori", override with WithTargetingKey) plus any static attributes from WithAttributes. This is not per-user targeting - a mamori field holds one value for the whole process, not one per request. Targeting that varies per end user belongs in your application’s own OpenFeature calls, not in a config field.

Error classification

Beyond not-found, Resolve classifies the OpenFeature error code carried on the evaluation result:

Watch

This provider is not watchable: OpenFeature has no per-flag change signal exposed uniformly enough at the client level to subscribe to across vendors, so mamori polls it (WithPollInterval + jitter).

Configuration

import (
	"github.com/open-feature/go-sdk/openfeature"
	ofprov "github.com/xavidop/mamori/providers/openfeature"
)

openfeature.SetProvider(myVendorProvider) // your application's own OpenFeature wiring

mamori.WithProvider(ofprov.New(
	ofprov.WithTargetingKey("checkout-service"),
	ofprov.WithAttributes(map[string]any{"region": "eu-west-1"}),
))

Verified with an injected fake openfeature.IClient (fallback-chain order and stopping, all eight OpenFeature error codes, targeting key/attributes, and the full providertest conformance suite). There is no vendor-specific integration test: this provider evaluates through whatever FeatureProvider your own application installs, so exercising it against a real backend is a choice made in your application, not here.