Make Icinga\Module\Icingadb\Common\IcingaRedis a singleton

This limits the connection attempts and established connections
to a single one. Previously we made as many as we've accessed redis.

application/forms/RedisConfigForm.php

@@ -20,8 +20,6 @@ use Zend_Validate_Callback;
 
 class RedisConfigForm extends ConfigForm
 {
-    use IcingaRedis;
-
     public function init()
     {
         $this->setSubmitLabel(t('Save Changes'));
@@ -482,7 +480,7 @@ class RedisConfigForm extends ConfigForm
         $redisConfig->setSection('redis2', $sections['redis2'] ?? []);
 
         try {
-            $redis1 = $form->getPrimaryRedis($moduleConfig, $redisConfig);
+            $redis1 = IcingaRedis::getPrimaryRedis($moduleConfig, $redisConfig);
         } catch (Exception $e) {
             $form->warning(sprintf(
                 t('Failed to connect to primary Redis: %s'),
@@ -491,19 +489,19 @@ class RedisConfigForm extends ConfigForm
             return false;
         }
 
-        if ($form->getLastIcingaHeartbeat($redis1) === null) {
+        if (IcingaRedis::getLastIcingaHeartbeat($redis1) === null) {
             $form->warning(t('Primary connection established but failed to verify Icinga is connected as well.'));
             return false;
         }
 
         try {
-            $redis2 = $form->getSecondaryRedis($moduleConfig, $redisConfig);
+            $redis2 = IcingaRedis::getSecondaryRedis($moduleConfig, $redisConfig);
         } catch (Exception $e) {
             $form->warning(sprintf(t('Failed to connect to secondary Redis: %s'), $e->getMessage()));
             return false;
         }
 
-        if ($redis2 !== null && $form->getLastIcingaHeartbeat($redis2) === null) {
+        if ($redis2 !== null && IcingaRedis::getLastIcingaHeartbeat($redis2) === null) {
             $form->warning(t('Secondary connection established but failed to verify Icinga is connected as well.'));
             return false;
         }

library/Icingadb/Common/IcingaRedis.php

@@ -8,11 +8,28 @@ use Exception;
 use Icinga\Application\Config;
 use Predis\Client as Redis;
 
-trait IcingaRedis
+class IcingaRedis
 {
+    /** @var static The singleton */
+    protected static $instance;
+
     /** @var Redis Connection to the Icinga Redis */
     private $redis;
 
+    /**
+     * Get the singleton
+     *
+     * @return static
+     */
+    public static function instance(): self
+    {
+        if (self::$instance === null) {
+            self::$instance = new static();
+        }
+
+        return self::$instance;
+    }
+
     /**
      * Get the connection to the Icinga Redis
      *
@@ -20,7 +37,7 @@ trait IcingaRedis
      *
      * @throws Exception
      */
-    public function getIcingaRedis()
+    public function getConnection()
     {
         if ($this->redis === null) {
             try {
@@ -63,8 +80,12 @@ trait IcingaRedis
         return $this->redis;
     }
 
-    public function getLastIcingaHeartbeat(Redis $redis)
+    public static function getLastIcingaHeartbeat(Redis $redis = null)
     {
+        if ($redis === null) {
+            $redis = self::instance()->getConnection();
+        }
+
         // Predis doesn't support streams (yet).
         // https://github.com/predis/predis/issues/607#event-3640855190
         $rs = $redis->executeRaw(['XREAD', 'COUNT', '1', 'STREAMS', 'icinga:stats', '0']);
@@ -90,7 +111,7 @@ trait IcingaRedis
         return null;
     }
 
-    public function getPrimaryRedis(Config $moduleConfig = null, Config $redisConfig = null)
+    public static function getPrimaryRedis(Config $moduleConfig = null, Config $redisConfig = null)
     {
         if ($moduleConfig === null) {
             $moduleConfig = Config::module('icingadb');
@@ -106,14 +127,14 @@ trait IcingaRedis
             'host'      => $section->get('host', 'localhost'),
             'port'      => $section->get('port', 6380),
             'timeout'   => 0.5
-        ] + $this->getTlsParams($moduleConfig));
+        ] + static::getTlsParams($moduleConfig));
 
         $redis->ping();
 
         return $redis;
     }
 
-    public function getSecondaryRedis(Config $moduleConfig = null, Config $redisConfig = null)
+    public static function getSecondaryRedis(Config $moduleConfig = null, Config $redisConfig = null)
     {
         if ($moduleConfig === null) {
             $moduleConfig = Config::module('redis');
@@ -134,14 +155,14 @@ trait IcingaRedis
             'host'      => $host,
             'port'      => $section->get('port', 6380),
             'timeout'   => 0.5
-        ] + $this->getTlsParams($moduleConfig));
+        ] + static::getTlsParams($moduleConfig));
 
         $redis->ping();
 
         return $redis;
     }
 
-    private function getTlsParams(Config $config)
+    private static function getTlsParams(Config $config)
     {
         $config = $config->getSection('redis');
 

library/Icingadb/Common/ObjectInspectionDetail.php

@@ -22,8 +22,6 @@ use ipl\Orm\Model;
 
 abstract class ObjectInspectionDetail extends BaseHtmlElement
 {
-    use IcingaRedis;
-
     protected $tag = 'div';
 
     protected $defaultAttributes = ['class' => ['object-detail', 'inspection-detail']];
@@ -101,7 +99,7 @@ abstract class ObjectInspectionDetail extends BaseHtmlElement
         $title = new HtmlElement('h2', null, Text::create(t('Volatile State Details')));
 
         try {
-            $json = $this->getIcingaRedis()
+            $json = IcingaRedis::instance()->getConnection()
                 ->hGet("icinga:{$this->object->getTableName()}:state", bin2hex($this->object->id));
         } catch (Exception $e) {
             return [$title, sprintf('Failed to load redis data: %s', $e->getMessage())];

library/Icingadb/Model/Behavior/VolatileState.php

@@ -12,14 +12,12 @@ use ipl\Orm\Model;
 
 class VolatileState implements RetrieveBehavior
 {
-    use IcingaRedis;
-
     protected $state;
 
     protected function getVolatileState()
     {
         if ($this->state === null) {
-            $this->state = new RedisState($this->getIcingaRedis());
+            $this->state = new RedisState(IcingaRedis::instance()->getConnection());
         }
 
         return $this->state;

library/Icingadb/ProvidedHook/ApplicationState.php

@@ -15,7 +15,6 @@ use ipl\Stdlib\Filter;
 class ApplicationState extends ApplicationStateHook
 {
     use Database;
-    use IcingaRedis;
 
     public function collectMessages()
     {
@@ -52,11 +51,7 @@ class ApplicationState extends ApplicationStateHook
         $outdatedDbHeartbeat = $instance->heartbeat < time() - 60;
 
         try {
-            $redis = $this->getIcingaRedis();
-
-            Session::getSession()->getNamespace('icingadb')->delete('redis.down-since');
-
-            $lastIcingaHeartbeat = $this->getLastIcingaHeartbeat($redis);
+            $lastIcingaHeartbeat = IcingaRedis::getLastIcingaHeartbeat();
             if ($lastIcingaHeartbeat === null) {
                 $missingSince = Session::getSession()
                     ->getNamespace('icingadb')->get('redis.heartbeat-missing-since');
@@ -93,6 +88,8 @@ class ApplicationState extends ApplicationStateHook
 
                     break;
             }
+
+            Session::getSession()->getNamespace('icingadb')->delete('redis.down-since');
         } catch (Exception $e) {
             $downSince = Session::getSession()->getNamespace('icingadb')->get('redis.down-since');
 

library/Icingadb/ProvidedHook/RedisHealth.php

@@ -13,7 +13,6 @@ use Icinga\Module\Icingadb\Model\Instance;
 class RedisHealth extends HealthHook
 {
     use Database;
-    use IcingaRedis;
 
     public function getName()
     {
@@ -23,9 +22,7 @@ class RedisHealth extends HealthHook
     public function checkHealth()
     {
         try {
-            $redis = $this->getIcingaRedis();
-
-            $lastIcingaHeartbeat = $this->getLastIcingaHeartbeat($redis);
+            $lastIcingaHeartbeat = IcingaRedis::getLastIcingaHeartbeat();
             if ($lastIcingaHeartbeat === null) {
                 $lastIcingaHeartbeat = time();
             }

library/Icingadb/Setup/RedisPage.php

@@ -4,14 +4,11 @@
 
 namespace Icinga\Module\Icingadb\Setup;
 
-use Icinga\Module\Icingadb\Common\IcingaRedis;
 use Icinga\Module\Icingadb\Forms\RedisConfigForm;
 use Icinga\Web\Form;
 
 class RedisPage extends Form
 {
-    use IcingaRedis;
-
     public function init()
     {
         $this->setName('setup_icingadb_redis');