MC-18948: Switch default search engine from MySQL to ElasticSearch

- add default engine

Author: cpartica

app/code/Magento/Elasticsearch/etc/di.xml

@@ -227,6 +227,7 @@
             <argument name="engines" xsi:type="array">
                 <item name="elasticsearch5" xsi:type="string">elasticsearch5</item>
             </argument>
+            <argument name="defaultEngine" xsi:type="string">elasticsearch5</argument>
         </arguments>
     </type>
     <virtualType name="Magento\Elasticsearch\SearchAdapter\ProductEntityMetadata" type="Magento\Framework\Search\EntityMetadata">

app/code/Magento/Elasticsearch6/etc/di.xml

@@ -77,6 +77,7 @@
             <argument name="engines" xsi:type="array">
                 <item name="elasticsearch6" xsi:type="string">elasticsearch6</item>
             </argument>
+            <argument name="defaultEngine" xsi:type="string">elasticsearch6</argument>
         </arguments>
     </type>
 

app/code/Magento/Elasticsearch7/etc/di.xml

@@ -85,6 +85,7 @@
             <argument name="engines" xsi:type="array">
                 <item name="elasticsearch7" xsi:type="string">elasticsearch7</item>
             </argument>
+            <argument name="defaultEngine" xsi:type="string">elasticsearch7</argument>
         </arguments>
     </type>
 

app/code/Magento/Search/Model/EngineResolver.php

@@ -61,28 +61,36 @@ class EngineResolver implements EngineResolverInterface
      */
     private $logger;
 
+    /**
+     * @var string
+     */
+    private $defaultEngine;
+
     /**
      * @param ScopeConfigInterface $scopeConfig
      * @param array $engines
      * @param LoggerInterface $logger
      * @param string $path
      * @param string $scopeType
      * @param string|null $scopeCode
+     * @param string|null $defaultEngine
      */
     public function __construct(
         ScopeConfigInterface $scopeConfig,
         array $engines,
         LoggerInterface $logger,
         $path,
         $scopeType,
-        $scopeCode = null
+        $scopeCode = null,
+        $defaultEngine = null
     ) {
         $this->scopeConfig = $scopeConfig;
         $this->path = $path;
         $this->scopeType = $scopeType;
         $this->scopeCode = $scopeCode;
         $this->engines = $engines;
         $this->logger = $logger;
+        $this->defaultEngine = $defaultEngine;
     }
 
     /**
@@ -105,15 +113,16 @@ public function getCurrentSearchEngine()
             return $engine;
         } else {
             //get default engine from default scope
-            $defaultEngine = $this->scopeConfig->getValue(
-                $this->path
-            );
-            if (in_array($defaultEngine, $this->engines)) {
+            if ($this->defaultEngine && in_array($this->defaultEngine, $this->engines)) {
+                $this->logger->error(
+                    $engine . ' search engine doesn\'t exist. Falling back to ' . $this->defaultEngine
+                );
+            } else {
                 $this->logger->error(
-                    $engine . ' search engine doesn\'t exist. Falling back to ' . $defaultEngine
+                    'Default search engine is not configured, fallback is not possible'
                 );
             }
-            return $defaultEngine;
+            return $this->defaultEngine;
         }
     }
 }

app/code/Magento/Search/Test/Unit/Model/EngineResolverTest.php

@@ -46,6 +46,11 @@ class EngineResolverTest extends \PHPUnit\Framework\TestCase
      */
     private $loggerMock;
 
+    /**
+     * @var string
+     */
+    private $defaultEngine = 'defaultentengine';
+
     /**
      * Setup
      *
@@ -70,7 +75,8 @@ protected function setUp()
             $this->loggerMock,
             $this->path,
             $this->scopeType,
-            $this->scopeCode
+            $this->scopeCode,
+            $this->defaultEngine
         );
     }
 
@@ -93,23 +99,48 @@ public function testGetCurrentSearchEngine()
      */
     public function testGetCurrentSearchEngineDefaultEngine()
     {
-        $engine = 'nonexistentengine';
-        $defaultEngine = 'defaultentengine';
+        $configEngine = 'nonexistentengine';
 
-        $this->scopeConfig->expects($this->at(0))
+        $this->scopeConfig->expects($this->any())
             ->method('getValue')
-            ->willReturn($engine);
+            ->willReturn($configEngine);
+
+        $this->loggerMock->expects($this->any())
+            ->method('error')
+            ->with(
+                "{$configEngine} search engine doesn't exist. Falling back to {$this->defaultEngine}"
+            );
+
+        $this->assertEquals($this->defaultEngine, $this->model->getCurrentSearchEngine());
+    }
 
-        $this->scopeConfig->expects($this->at(1))
+    /**
+     * Test getCurrentSearchEngine
+     */
+    public function testGetCurrentSearchEngineDefaultEngineNonExistent()
+    {
+        $configEngine = 'nonexistentengine';
+        $this->defaultEngine = 'nonexistenddefaultengine';
+
+        $this->scopeConfig->expects($this->any())
             ->method('getValue')
-            ->willReturn($defaultEngine);
+            ->willReturn($configEngine);
 
         $this->loggerMock->expects($this->any())
             ->method('error')
             ->with(
-                "{$engine} search engine doesn't exist. Falling back to {$defaultEngine}"
+                'Default search engine is not configured, fallback is not possible'
             );
 
-        $this->assertEquals($defaultEngine, $this->model->getCurrentSearchEngine());
+        $model = new EngineResolver(
+            $this->scopeConfig,
+            $this->engines,
+            $this->loggerMock,
+            $this->path,
+            $this->scopeType,
+            $this->scopeCode,
+            $this->defaultEngine
+        );
+        $this->assertEquals($this->defaultEngine, $model->getCurrentSearchEngine());
     }
 }