'Digit2Html' => __DIR__ . '/maintenance/language/digit2html.php',
'DjVuHandler' => __DIR__ . '/includes/media/DjVu.php',
'DjVuImage' => __DIR__ . '/includes/media/DjVuImage.php',
+ 'DnsSrvDiscoverer' => __DIR__ . '/includes/libs/DnsSrvDiscoverer.php',
'DoubleRedirectJob' => __DIR__ . '/includes/jobqueue/jobs/DoubleRedirectJob.php',
'DoubleRedirectsPage' => __DIR__ . '/includes/specials/SpecialDoubleRedirects.php',
'DoubleReplacer' => __DIR__ . '/includes/libs/replacers/DoubleReplacer.php',
--- /dev/null
+<?php
+/**
+ * Service discovery using DNS SRV records
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+/**
+ * @since 1.29
+ */
+class DnsSrvDiscoverer {
+ /**
+ * @var string
+ */
+ private $domain;
+
+ /**
+ * @param string $domain
+ */
+ public function __construct( $domain ) {
+ $this->domain = $domain;
+ }
+
+ /**
+ * Fetch the servers with a DNS SRV request
+ *
+ * @return array
+ */
+ public function getServers() {
+ $result = [];
+ foreach ( $this->getDnsRecords() as $record ) {
+ $result[] = [
+ 'target' => $record['target'],
+ 'port' => $record['port'],
+ 'pri' => $record['pri'],
+ 'weight' => $record['weight'],
+ ];
+ }
+
+ return $result;
+ }
+
+ /**
+ * Pick a server according to the priority fields.
+ * Note that weight is currently ignored.
+ *
+ * @param array $servers from getServers
+ * @return array|bool
+ */
+ public function pickServer( array $servers ) {
+ if ( !$servers ) {
+ return false;
+ }
+
+ $srvsByPrio = [];
+ foreach ( $servers as $server ) {
+ $srvsByPrio[$server['pri']][] = $server;
+ }
+
+ $min = min( array_keys( $srvsByPrio ) );
+ if ( count( $srvsByPrio[$min] ) == 1 ) {
+ return $srvsByPrio[$min][0];
+ } else {
+ // Choose randomly
+ $rand = mt_rand( 0, count( $srvsByPrio[$min] ) - 1 );
+
+ return $srvsByPrio[$min][$rand];
+ }
+ }
+
+ /**
+ * @return array[]
+ */
+ protected function getDnsRecords() {
+ return dns_get_record( $this->domain, DNS_SRV );
+ }
+}
--- /dev/null
+<?php
+
+class DnsSrvDiscovererTest extends PHPUnit_Framework_TestCase {
+ /**
+ * @covers DnsSrvDiscoverer
+ * @dataProvider provideRecords
+ */
+ public function testPickServer( $params, $expected ) {
+ $discoverer = new DnsSrvDiscoverer( '_etcd._tcp.eqiad.wmnet' );
+ $record = $discoverer->pickServer( $params );
+
+ $this->assertEquals( $expected, $record );
+
+ }
+
+ public static function provideRecords() {
+ return [
+ [
+ [ // record list
+ [
+ 'target' => 'conf1003.eqiad.wmnet',
+ 'port' => 'SRV',
+ 'pri' => 0,
+ 'weight' => 1,
+ ],
+ [
+ 'target' => 'conf1002.eqiad.wmnet',
+ 'port' => 'SRV',
+ 'pri' => 1,
+ 'weight' => 1,
+ ],
+ [
+ 'target' => 'conf1001.eqiad.wmnet',
+ 'port' => 'SRV',
+ 'pri' => 2,
+ 'weight' => 1,
+ ],
+ ], // selected record
+ [
+ 'target' => 'conf1003.eqiad.wmnet',
+ 'port' => 'SRV',
+ 'pri' => 0,
+ 'weight' => 1,
+ ]
+ ],
+ [
+ [ // record list
+ [
+ 'target' => 'conf1003or2.eqiad.wmnet',
+ 'port' => 'SRV',
+ 'pri' => 0,
+ 'weight' => 1,
+ ],
+ [
+ 'target' => 'conf1003or2.eqiad.wmnet',
+ 'port' => 'SRV',
+ 'pri' => 0,
+ 'weight' => 1,
+ ],
+ [
+ 'target' => 'conf1001.eqiad.wmnet',
+ 'port' => 'SRV',
+ 'pri' => 2,
+ 'weight' => 1,
+ ],
+ [
+ 'target' => 'conf1004.eqiad.wmnet',
+ 'port' => 'SRV',
+ 'pri' => 2,
+ 'weight' => 1,
+ ],
+ [
+ 'target' => 'conf1005.eqiad.wmnet',
+ 'port' => 'SRV',
+ 'pri' => 3,
+ 'weight' => 1,
+ ],
+ ], // selected record
+ [
+ 'target' => 'conf1003or2.eqiad.wmnet',
+ 'port' => 'SRV',
+ 'pri' => 0,
+ 'weight' => 1,
+ ]
+ ],
+ ];
+ }
+}