Checking if elasticsearch can connect to host / port (bug #1256118)

Currently the getConnection() in Elastica/Client.php can give false
positive and also throws error if no connection.

What is needed is a true/false check to allow for things like notice
feedback on extensions page or giving a warning when switching to
'elasticsearch' on site options page when it is unreachable.

Change-Id: I43506f03b943d79eb019d39fe794037fc50bd05a
Signed-off-by: Robert Lyon <robertl@catalyst.net.nz>

htdocs/admin/site/options.php

@@ -760,7 +760,13 @@ function siteoptions_submit(Pieform $form, $values) {
         call_static_method(generate_class_name('search', $oldsearchplugin), 'cleanup_sitewide');
         // Call the new search plugin's sitewide initialize method
         safe_require('search', $values['searchplugin']);
-        call_static_method(generate_class_name('search', $values['searchplugin']), 'initialize_sitewide');
+        $initialize = call_static_method(generate_class_name('search', $values['searchplugin']), 'initialize_sitewide');
+        if (!$initialize) {
+            $form->reply(PIEFORM_ERR, array(
+                'message' => get_string('searchconfigerror', 'admin', $values['searchplugin']),
+                'goto'    => '/admin/site/options.php',
+            ));
+        }
     }
 
     // submitted sessionlifetime is in minutes; db entry session_timeout is in seconds

htdocs/lang/en.utf8/admin.php

@@ -339,6 +339,7 @@ $string['remoteavatars'] = 'Display remote avatars';
 $string['remoteavatarsdescription'] = 'If checked, the <a href="http://www.gravatar.com">Gravatar</a> service will be used for users\' default profile pictures.';
 $string['searchplugin'] = 'Search plugin';
 $string['searchplugindescription'] = 'Search plugin to use';
+$string['searchconfigerror'] = 'The configuration settings for search plugin "%s" are incorrect, please check the configuration settings under Extensions -> Plugin type: search. You may need to hit the search\'s \'reset\' button when done.';
 $string['searchusernames'] = 'Search usernames';
 $string['searchusernamesdescription'] = 'If checked, allow usernames to be searched on as part of "Search users".';
 $string['sessionlifetime'] = 'Session lifetime';

htdocs/search/elasticsearch/lang/en.utf8/search.elasticsearch.php

@@ -44,6 +44,7 @@ $string['indexnamedescription'] = 'Name of the Elasticsearch index. Default is m
 $string['license'] = 'License';
 $string['Media'] = 'Media';
 $string['noticeenabled'] = 'The Elasticsearch plugin is currently active. To deactivate it, deselect it in the <a href="%s">site options search settings</a>.';
+$string['noticenotactive'] = 'The ElasticSearch Server is unreachable on host: %s and port %s. Please make sure it is running.';
 $string['noticenotenabled'] = 'The Elasticsearch plugin is not currently enabled. To activate it, select it in the <a href="%s">site options in the search settings</a>.';
 $string['noticepostgresrequired'] = 'The Elasticsearch plugin only works with a PostgreSQL database at this time.';
 $string['noticepostgresrequiredtitle'] = 'Feature not available';

htdocs/search/elasticsearch/lib.php

@@ -80,6 +80,20 @@ class PluginSearchElasticsearch extends PluginSearch {
         return is_postgres();
     }
 
+    /**
+     * This function determines if we can connect to the supplied host and port
+     */
+    public static function can_connect() {
+        $host = get_config_plugin('search', 'elasticsearch', 'host');
+        $port = get_config_plugin('search', 'elasticsearch', 'port');
+        $fp = @fsockopen($host, $port, $errno, $errstr, 5);
+        if ($fp) {
+            fclose($fp);
+            return true;
+        }
+        return false;
+    }
+
     /**
      * Generates the search form used in the page headers
      * @return string
@@ -147,6 +161,12 @@ class PluginSearchElasticsearch extends PluginSearch {
             $enabledhtml = $smarty->fetch('Search:elasticsearch:configwarning.tpl');
             unset($smarty);
         }
+        if (!self::can_connect()) {
+            $smarty = smarty_core();
+            $smarty->assign('notice', get_string('noticenotactive', 'search.elasticsearch', get_config_plugin('search', 'elasticsearch', 'host'), get_config_plugin('search', 'elasticsearch', 'port')));
+            $enabledhtml .= $smarty->fetch('Search:elasticsearch:configwarning.tpl');
+            unset($smarty);
+        }
 
         $config = array(
             'elements' => array(
@@ -393,7 +413,11 @@ class PluginSearchElasticsearch extends PluginSearch {
      *
      */
     public static function initialize_sitewide() {
-        self::reset_all_searchtypes();
+        if (self::can_connect()) {
+            self::reset_all_searchtypes();
+            return true;
+        }
+        return false;
     }
 
     /**