Reset the assigned signaling server after some time

Signed-off-by: Joas Schilling <coding@schilljs.com>

appinfo/info.xml

@@ -16,7 +16,7 @@ And in the works for the [coming versions](https://github.com/nextcloud/spreed/m
 
 	]]></description>
 
-	<version>9.0.0-dev.6</version>
+	<version>9.0.0-dev.7</version>
 	<licence>agpl</licence>
 
 	<author>Daniel Calviño Sánchez</author>
@@ -52,6 +52,7 @@ And in the works for the [coming versions](https://github.com/nextcloud/spreed/m
 	<background-jobs>
 		<job>OCA\Talk\BackgroundJob\ExpireSignalingMessage</job>
 		<job>OCA\Talk\BackgroundJob\RemoveEmptyRooms</job>
+		<job>OCA\Talk\BackgroundJob\ResetAssignedSignalingServer</job>
 	</background-jobs>
 
 	<repair-steps>

lib/BackgroundJob/ResetAssignedSignalingServer.php

@@ -0,0 +1,49 @@
+<?php
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2020, Joas Schilling <coding@schilljs.com>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OCA\Talk\BackgroundJob;
+
+use OC\BackgroundJob\TimedJob;
+use OCA\Talk\Manager;
+use OCP\ICache;
+use OCP\ICacheFactory;
+
+class ResetAssignedSignalingServer extends TimedJob {
+
+	/** @var Manager */
+	protected $manager;
+	/** @var ICache */
+	protected $cache;
+
+	public function __construct(Manager $manager,
+								ICacheFactory $cacheFactory) {
+		// Every 5 minutes
+		$this->setInterval(60 * 5);
+
+		$this->manager = $manager;
+		$this->cache = $cacheFactory->createDistributed('hpb_servers');
+	}
+
+	protected function run($argument): void {
+		$this->manager->resetAssignedSignalingServers($this->cache);
+	}
+}

lib/Manager.php

@@ -34,6 +34,7 @@ use OCP\Comments\IComment;
 use OCP\Comments\NotFoundException;
 use OCP\DB\QueryBuilder\IQueryBuilder;
 use OCP\EventDispatcher\IEventDispatcher;
+use OCP\ICache;
 use OCP\IConfig;
 use OCP\IDBConnection;
 use OCP\IL10N;
@@ -207,6 +208,23 @@ class Manager {
 		}
 	}
 
+	public function resetAssignedSignalingServers(ICache $cache): void {
+		$query = $this->db->getQueryBuilder();
+		$query->select('*')
+			->from('talk_rooms')
+			->where($query->expr()->isNotNull('assigned_hpb'));
+
+		$result = $query->execute();
+		while ($row = $result->fetch()) {
+			$room = $this->createRoomObject($row);
+			if (!$room->hasActiveSessions()) {
+				$room->setAssignedSignalingServer(null);
+				$cache->remove($room->getToken());
+			}
+		}
+		$result->closeCursor();
+	}
+
 	/**
 	 * @param string $participant
 	 * @param bool $includeLastMessage

lib/Room.php

@@ -1127,6 +1127,23 @@ class Room {
 		return $participants;
 	}
 
+	/**
+	 * @return bool
+	 */
+	public function hasActiveSessions(): bool {
+		$query = $this->db->getQueryBuilder();
+		$query->select('room_id')
+			->from('talk_participants')
+			->where($query->expr()->eq('room_id', $query->createNamedParameter($this->getId(), IQueryBuilder::PARAM_INT)))
+			->andWhere($query->expr()->neq('session_id', $query->createNamedParameter('0')))
+			->setMaxResults(1);
+		$result = $query->execute();
+		$row = $result->fetch();
+		$result->closeCursor();
+
+		return (bool) $row;
+	}
+
 	/**
 	 * @return string[]
 	 */