New feature: override configurations with env variables

app/code/core/Mage/Core/Helper/EnvironmentConfigLoader.php

@@ -0,0 +1,132 @@
+<?php
+/**
+ * OpenMage
+ *
+ * This source file is subject to the Open Software License (OSL 3.0)
+ * that is bundled with this package in the file LICENSE.txt.
+ * It is also available at https://opensource.org/license/osl-3-0-php
+ *
+ * @category   Mage
+ * @package    Mage_Core
+ * @copyright  Copyright (c) 2006-2020 Magento, Inc. (https://www.magento.com)
+ * @copyright  Copyright (c) 2016-present The OpenMage Contributors (https://www.openmage.org)
+ * @license    https://opensource.org/licenses/osl-3.0.php  Open Software License (OSL 3.0)
+ */
+
+/**
+ * Core Environment helper
+ *
+ * @category   Mage
+ * @package    Mage_Core
+ */
+class Mage_Core_Helper_EnvironmentConfigLoader extends Mage_Core_Helper_Abstract
+{
+    protected $_moduleName = 'Mage_Core';
+    protected const ENV_STARTS_WITH = 'OPENMAGE_CONFIG';
+    protected const ENV_KEY_SEPARATOR = '__';
+    protected const CONFIG_KEY_DEFAULT = 'DEFAULT';
+    protected const CONFIG_KEY_WEBSITES = 'WEBSITES';
+    protected const CONFIG_KEY_STORES = 'STORES';
+
+    protected array $envStore = [];
+
+    /**
+     * Load configuration values from ENV variables into xml config object
+     *
+     * Environment variables work on this schema:
+     *
+     * self::ENV_STARTS_WITH . self::ENV_KEY_SEPARATOR (OPENMAGE_CONFIG__)
+     *        ^ Prefix (required)
+     *                  <SCOPE>__
+     *                     ^ Where scope is DEFAULT, WEBSITES__<WEBSITE_CODE> or STORES__<STORE_CODE>
+     *                           <SYSTEM_VARIABLE_NAME>
+     *                                   ^ Where GROUP, SECTION and FIELD are separated by self::ENV_KEY_SEPARATOR
+     *
+     * Each example will override the 'general/store_information/name' value.
+     * Override from the default configuration:
+     * @example OPENMAGE_CONFIG__DEFAULT__GENERAL__STORE_INFORMATION__NAME=default
+     * Override the website 'base' configuration:
+     * @example OPENMAGE_CONFIG__WEBSITES__BASE__GENERAL__STORE_INFORMATION__NAME=website
+     * Override the store 'german' configuration:
+     * @example OPENMAGE_CONFIG__STORES__GERMAN__GENERAL__STORE_INFORMATION__NAME=store_german
+     *
+     * @param Varien_Simplexml_Config $xmlConfig
+     * @return void
+     */
+    public function overrideEnvironment(Varien_Simplexml_Config $xmlConfig)
+    {
+        $env = $this->getEnv();
+
+        foreach ($env as $configKey => $value) {
+            if (!str_starts_with($configKey, static::ENV_STARTS_WITH)) {
+                continue;
+            }
+
+            $configKeyParts = array_filter(
+                explode(
+                    static::ENV_KEY_SEPARATOR,
+                    $configKey
+                ),
+                'trim'
+            );
+            list($_, $scope) = $configKeyParts;
+
+            switch ($scope) {
+                case static::CONFIG_KEY_DEFAULT:
+                    list($_, $_, $section, $group, $field) = $configKeyParts;
+                    $path = $this->buildPath($section, $group, $field);
+                    $xmlConfig->setNode($this->buildNodePath($scope, $path), $value);
+                    break;
+
+                case static::CONFIG_KEY_WEBSITES:
+                case static::CONFIG_KEY_STORES:
+                    list($_, $_, $code, $section, $group, $field) = $configKeyParts;
+                    $path = $this->buildPath($section, $group, $field);
+                    $nodePath = sprintf('%s/%s/%s', strtolower($scope), strtolower($code), $path);
+                    $xmlConfig->setNode($nodePath, $value);
+                    break;
+            }
+        }
+    }
+
+    /**
+     * @internal method mostly for mocking
+     */
+    public function setEnvStore(array $envStorage): void
+    {
+        $this->envStore = $envStorage;
+    }
+
+    public function getEnv(): array
+    {
+        if (empty($this->envStore)) {
+            $this->envStore = getenv();
+        }
+        return $this->envStore;
+    }
+
+    /**
+     * Build configuration path.
+     *
+     * @param string $section
+     * @param string $group
+     * @param string $field
+     * @return string
+     */
+    public function buildPath($section, $group, $field): string
+    {
+        return strtolower(implode('/', [$section, $group, $field]));
+    }
+
+    /**
+     * Build configuration node path.
+     *
+     * @param string $scope
+     * @param string $path
+     * @return string
+     */
+    public function buildNodePath($scope, $path): string
+    {
+        return strtolower($scope) . '/' . $path;
+    }
+}

app/code/core/Mage/Core/Model/App.php

@@ -442,6 +442,7 @@ protected function _initModules()
                         Varien_Profiler::stop('mage::app::init::apply_db_schema_updates');
                     }
                     $this->_config->loadDb();
+                    $this->_config->loadEnv();
                     $this->_config->saveCache();
                 }
             } finally {

app/code/core/Mage/Core/Model/Config.php

@@ -320,6 +320,7 @@ public function init($options = [])
                     $this->_useCache = false;
                     $this->loadModules();
                     $this->loadDb();
+                    $this->loadEnv();
                     $this->saveCache();
                 }
             } finally {
@@ -422,6 +423,23 @@ public function loadDb()
         return $this;
     }
 
+    /**
+     * Load environment variables and override config
+     *
+     * @return self
+     */
+    public function loadEnv(): Mage_Core_Model_Config
+    {
+        if ($this->_isLocalConfigLoaded && Mage::isInstalled()) {
+            Varien_Profiler::start('config/load-env');
+            /** @var Mage_Core_Helper_EnvironmentConfigLoader $environmentConfigLoaderHelper */
+            $environmentConfigLoaderHelper = Mage::helper('core/environmentConfigLoader');
+            $environmentConfigLoaderHelper->overrideEnvironment($this);
+            Varien_Profiler::stop('config/load-env');
+        }
+        return $this;
+    }
+
     /**
      * Reinitialize configuration
      *

dev/tests/unit/Mage/Core/Helper/EnvironmentConfigLoaderTest.php

@@ -0,0 +1,152 @@
+<?php
+declare(strict_types=1);
+
+namespace OpenMage\Tests\Unit\Core\Helper;
+
+use PHPUnit\Framework\TestCase;
+use Mage_Core_Helper_EnvironmentConfigLoader;
+use Mage_Core_Model_Config;
+
+class EnvironmentConfigLoaderTest extends TestCase
+{
+    protected const ENV_CONFIG_DEFAULT_PATH = 'OPENMAGE_CONFIG__DEFAULT__GENERAL__STORE_INFORMATION__NAME';
+    protected const ENV_CONFIG_DEFAULT_VALUE = 'default_new_value';
+    protected const ENV_CONFIG_WEBSITE_PATH = 'OPENMAGE_CONFIG__WEBSITES__BASE__GENERAL__STORE_INFORMATION__NAME';
+    protected const ENV_CONFIG_WEBSITE_VALUE = 'website_new_value';
+    protected const ENV_CONFIG_STORE_PATH = 'OPENMAGE_CONFIG__STORES__GERMAN__GENERAL__STORE_INFORMATION__NAME';
+    protected const ENV_CONFIG_STORE_VALUE = 'store_german_new_value';
+
+    public function setup(): void
+    {
+        \Mage::setRoot('');
+    }
+
+    public function testBuildPath()
+    {
+        $environmentConfigLoaderHelper = new Mage_Core_Helper_EnvironmentConfigLoader();
+        $path = $environmentConfigLoaderHelper->buildPath('GENERAL', 'STORE_INFORMATION', 'NAME');
+        $this->assertEquals('general/store_information/name', $path);
+    }
+
+    public function testBuildNodePath()
+    {
+        $loader = new Mage_Core_Helper_EnvironmentConfigLoader();
+        $nodePath = $loader->buildNodePath('DEFAULT', 'general/store_information/name');
+        $this->assertEquals('default/general/store_information/name', $nodePath);
+    }
+
+    /**
+     * @dataProvider envOverridesDataProvider
+     *
+     */
+    public function testEnvOverrides(array $config)
+    {
+        $xmlStruct = $this->getTestXml();
+
+        $xmlDefault = new \Varien_Simplexml_Config();
+        $xmlDefault->loadString($xmlStruct);
+        $xml = new \Varien_Simplexml_Config();
+        $xml->loadString($xmlStruct);
+
+        $this->assertEquals('test_default', (string)$xml->getNode('default/general/store_information/name'));
+        $this->assertEquals('test_website', (string)$xml->getNode('websites/base/general/store_information/name'));
+        $this->assertEquals('test_store', (string)$xml->getNode('stores/german/general/store_information/name'));
+
+        // act
+        $loader = new Mage_Core_Helper_EnvironmentConfigLoader();
+        $loader->setEnvStore([
+            $config['path'] => $config['value']
+        ]);
+        $loader->overrideEnvironment($xml);
+
+        switch ($config['case']) {
+            case 'DEFAULT':
+                $defaultValue = $xmlDefault->getNode('default/general/store_information/name');
+                $valueAfterOverride = $xml->getNode('default/general/store_information/name');
+                break;
+            case 'STORE':
+                $defaultValue = $xmlDefault->getNode('stores/german/general/store_information/name');
+                $valueAfterOverride = $xml->getNode('general/store_information/name');
+                break;
+            case 'WEBSITE':
+                $defaultValue = $xmlDefault->getNode('default/general/store_information/name');
+                $valueAfterOverride = $xml->getNode('website/base/store_information/name');
+                break;
+        }
+
+        // assert
+        $this->assertNotEquals((string)$defaultValue, (string)$valueAfterOverride, 'Default value was not overridden.');
+    }
+
+    public function envOverridesDataProvider(): array
+    {
+        return [
+            [
+                'Case DEFAULT with ' . static::ENV_CONFIG_DEFAULT_PATH . ' overrides.' => [
+                    'case'  => 'DEFAULT',
+                    'path'  => static::ENV_CONFIG_DEFAULT_PATH,
+                    'value' => static::ENV_CONFIG_DEFAULT_VALUE
+                ]
+            ],
+            [
+                'Case STORE with ' . static::ENV_CONFIG_STORE_PATH . ' overrides.' => [
+                    'case'  => 'STORE',
+                    'path'  => static::ENV_CONFIG_STORE_PATH,
+                    'value' => static::ENV_CONFIG_STORE_VALUE
+                ]
+            ],
+            [
+                'Case WEBSITE with ' . static::ENV_CONFIG_WEBSITE_PATH . ' overrides.' => [
+                    'case'  => 'WEBSITE',
+                    'path'  => static::ENV_CONFIG_WEBSITE_PATH,
+                    'value' => static::ENV_CONFIG_WEBSITE_VALUE
+                ]
+            ]
+        ];
+    }
+
+    /**
+     * @return string
+     */
+    public function getTestXml(): string
+    {
+        return <<<XML
+<?xml version="1.0" encoding="UTF-8" ?>
+<config>
+    <modules>
+        <Mage_Core>
+            <active>true</active>
+            <codePool>core</codePool>
+        </Mage_Core>
+    </modules>
+
+    <default>
+        <general>
+            <store_information>
+                    <name>test_default</name>
+            </store_information>
+        </general>
+    </default>
+
+    <websites>
+        <base>
+            <general>
+                <store_information>
+                        <name>test_website</name>
+                </store_information>
+            </general>
+        </base>
+    </websites>
+    <stores>
+        <german>
+            <general>
+                <store_information>
+                        <name>test_store</name>
+                </store_information>
+            </general>
+        </german>
+    </stores>
+</config>
+XML;
+    }
+}