PrefetchCache, IcingaObject: speed up import list

...greatly improves REST API performance

library/Director/Db/Cache/PrefetchCache.php

@@ -7,6 +7,7 @@ use Icinga\Module\Director\CustomVariable\CustomVariable;
 use Icinga\Module\Director\Db;
 use Icinga\Module\Director\Objects\IcingaObject;
 use Icinga\Module\Director\Objects\IcingaTemplateResolver;
+use Icinga\Module\Director\Resolver\TemplateTree;
 
 /**
  * Central prefetch cache
@@ -29,6 +30,8 @@ class PrefetchCache
 
     protected $renderedVars = array();
 
+    protected $templateTrees = array();
+
     public static function initialize(Db $db)
     {
         self::$instance = new static($db);
@@ -78,6 +81,11 @@ class PrefetchCache
         return $this->templateResolver($object)->setObject($object)->fetchParents();
     }
 
+    public function listImportNames(IcingaObject $object)
+    {
+        return $this->templateTree($object)->listParentNamesForObject($object);
+    }
+
     /* Hint: not implemented, this happens in DbObject right now
     public function byObjectType($type)
     {
@@ -136,6 +144,19 @@ class PrefetchCache
         return $this->groupsCaches[$key];
     }
 
+    protected function templateTree(IcingaObject $object)
+    {
+        $key = $object->getShortTableName();
+        if (! array_key_exists($key, $this->templateTrees)) {
+            $this->templateTrees[$key] = new TemplateTree(
+                $key,
+                $object->getConnection()
+            );
+        }
+
+        return $this->templateTrees[$key];
+    }
+
     public function __destruct()
     {
         unset($this->groupsCaches);

library/Director/Objects/IcingaObject.php

@@ -18,6 +18,7 @@ use Icinga\Module\Director\IcingaConfig\IcingaConfig;
 use Icinga\Module\Director\IcingaConfig\IcingaConfigRenderer;
 use Icinga\Module\Director\IcingaConfig\IcingaConfigHelper as c;
 use Icinga\Module\Director\IcingaConfig\IcingaLegacyConfigHelper as c1;
+use Icinga\Module\Director\Resolver\TemplateTree;
 
 abstract class IcingaObject extends DbObject implements IcingaConfigRenderer
 {
@@ -130,6 +131,8 @@ abstract class IcingaObject extends DbObject implements IcingaConfigRenderer
 
     private $templateResolver;
 
+    protected static $tree;
+
     /**
      * @return Db
      */
@@ -2526,9 +2529,9 @@ abstract class IcingaObject extends DbObject implements IcingaConfigRenderer
 
         if ($this->supportsImports()) {
             if ($resolved) {
-                $props['imports'] = array();
+                $props['imports'] = [];
             } else {
-                $props['imports'] = $this->imports()->listImportNames();
+                $props['imports'] = $this->listImportNames();
             }
         }
 
@@ -2587,6 +2590,15 @@ abstract class IcingaObject extends DbObject implements IcingaConfigRenderer
         return (object) $props;
     }
 
+    public function listImportNames()
+    {
+        if (PrefetchCache::shouldBeUsed()) {
+            return PrefetchCache::instance()->listImportNames($this);
+        } else {
+            return $this->imports()->listImportNames();
+        }
+    }
+
     protected function differsFromDefaultValue($key, $value)
     {
         if (array_key_exists($key, $this->defaultProperties)) {