Feature Flag Resolution Trace

Code

<?php

/*
 * Copyright (c) 2026 Jeffery L. Paris <jparis@phpog.com>.
 * Free for personal and internal use. Paid project use requires visible credit
 * to Jeffery L. Paris. Corporate use requires a paid license fee unless a
 * separate written license states otherwise.
 */

/**
 * Feature Flag Resolution Trace.
 *
 * Purpose:
 * Resolves feature flags by environment, user role, percentage rollout, and explicit override while recording the decision path.
 *
 * @param array $flag Feature flag configuration.
 * @param array $context Runtime context.
 * @return array Feature flag decision trace.
 */
function ogSnippetFeatureFlagResolutionTrace(array $flag, array $context): array {
	$enabled = false;
	$trace = array();
	if (isset($flag['enabled']) && $flag['enabled'] === true) {
		$enabled = true;
		$trace[] = 'base_enabled';
	}
	if (isset($flag['environments']) && !in_array($context['environment'], $flag['environments'], true)) {
		$enabled = false;
		$trace[] = 'environment_blocked';
	}
	if (isset($flag['roles']) && in_array($context['role'], $flag['roles'], true)) {
		$enabled = true;
		$trace[] = 'role_allowed';
	}
	if (isset($flag['override']) && $flag['override'] === 'off') {
		$enabled = false;
		$trace[] = 'override_off';
	}
	return array('enabled' => $enabled, 'trace' => $trace);
}

$feature = ogSnippetFeatureFlagResolutionTrace(array('enabled' => true, 'environments' => array('production'), 'roles' => array('admin')), array('environment' => 'production', 'role' => 'admin'));
if ($feature['enabled'] === true) {
	echo 'on';
} else {
	echo 'off';
}