Added checker for MongoDB

Author: tkachuk

README.md

@@ -22,6 +22,7 @@ It currently ships with the following Diagnostic Checks:
  * [GuzzleHttpService](#guzzlehttpservice) - check if given http host is responding using Guzzle,
  * [HttpService](#httpservice) - check if given http host is responding,
  * [Memcache](#memcache) - check if memcache extension is loaded and given server is reachable,
+ * [Mongo](#mongodb) - check if connection to MongoDb is possible,
  * [OpCacheMemory](#opcachememory) - check if the OpCache memory usage is below warning/critical thresholds,
  * [PDOCheck](#pdocheck) - check if connection is possible,
  * [PhpVersion](#phpversion) - make sure that PHP version matches constraint,
@@ -487,6 +488,18 @@ $checkLocal  = new Memcache('127.0.0.1'); // default port
 $checkBackup = new Memcache('10.0.30.40', 11212);
 ````
 
+### MongoDb
+Check if connection to MongoDb is possible
+
+````php
+<?php
+use ZendDiagnostics\Check\Mongo;
+
+$mongoCheck = new Mongo('mongodb://127.0.0.1:27017');
+// and with user/password
+$mongoCheck = new Mongo('mongodb://user:[email protected]:27017');
+````
+
 ### PhpVersion
 
 Check if current PHP version matches the given requirement. The test accepts 2 parameters - baseline version and

src/ZendDiagnostics/Check/Mongo.php

@@ -0,0 +1,53 @@
+<?php
+namespace ZendDiagnostics\Check;
+
+use ZendDiagnostics\Result\Success;
+use ZendDiagnostics\Result\Failure;
+
+class Mongo extends AbstractCheck
+{
+    /**
+     * @var string
+     */
+    private $connectionUri;
+
+    /**
+     * @param string $connectionUri
+     */
+    public function __construct($connectionUri)
+    {
+        $this->connectionUri = $connectionUri;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function check()
+    {
+        try {
+            $this->getListDBs();
+        } catch (\Exception $e) {
+            return new Failure(sprintf('Failed to connect to MongoDB server. Reason: `%s`', $e->getMessage()));
+        }
+
+        return new Success();
+    }
+
+    /**
+     * @return array|\Iterator
+     *
+     * @throws \RuntimeException
+     * @throws \MongoDB\Driver\Exception
+     * @throws \MongoConnectionException
+     */
+    private function getListDBs()
+    {
+        if (class_exists('\MongoDB\Client')) {
+            return (new \MongoDB\Client($this->connectionUri))->listDatabases();
+        } elseif (class_exists('\MongoClient')) {
+            return (new \MongoClient($this->server))->listDBs();
+        }
+
+        throw new \RuntimeException('Neither the mongo extension or mongodb are installed');
+    }
+}