add SyslogHandler to Monolog

usage example:

   $log = new Logger('application');
   $syslog = new SyslogHandler('myfacility', 'local6');
   $formatter = new LineFormatter("%channel%.%level_name%: %message% %extra%");
   $syslog->setFormatter($formatter);
   $log->pushHandler($syslog);

src/Monolog/Handler/SyslogHandler.php

@@ -0,0 +1,93 @@
+<?php
+
+/*
+ * This file is part of the Monolog package.
+ *
+ * (c) Jordi Boggiano <j.boggiano@seld.be>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Monolog\Handler;
+
+use Monolog\Formatter\SimpleFormatter;
+use Monolog\Logger;
+
+/**
+ * Logs to syslog service.
+ * 
+ * usage example:
+ *
+ *   $log = new Logger('application');
+ *   $syslog = new SyslogHandler('myfacility', 'local6');
+ *   $formatter = new LineFormatter("%channel%.%level_name%: %message% %extra%");
+ *   $syslog->setFormatter($formatter);
+ *   $log->pushHandler($syslog);
+ *
+ * @author Sven Paulus <sven@karlsruhe.org>
+ */
+class SyslogHandler extends AbstractHandler
+{
+
+    /**
+     * Translate Monolog log levels to syslog log priorities.
+     */
+    private $logLevels = array(
+      Logger::DEBUG   => LOG_DEBUG,
+      Logger::INFO    => LOG_INFO,
+      Logger::WARNING => LOG_WARNING,
+      Logger::ERROR   => LOG_ERR,
+    );
+  
+    /**
+     * List of valid log facility names.
+     */
+    private $facilities = array(
+      'auth'     => LOG_AUTH,
+      'authpriv' => LOG_AUTHPRIV,
+      'cron'     => LOG_CRON,
+      'daemon'   => LOG_DAEMON,
+      'kern'     => LOG_KERN,
+      'local0'   => LOG_LOCAL0,
+      'local1'   => LOG_LOCAL1,
+      'local2'   => LOG_LOCAL2,
+      'local3'   => LOG_LOCAL3,
+      'local4'   => LOG_LOCAL4,
+      'local5'   => LOG_LOCAL5,
+      'local6'   => LOG_LOCAL6,
+      'local7'   => LOG_LOCAL7,
+      'lpr'      => LOG_LPR,
+      'mail'     => LOG_MAIL,
+      'news'     => LOG_NEWS,
+      'syslog'   => LOG_SYSLOG,
+      'user'     => LOG_USER,
+      'uucp'     => LOG_UUCP,
+    );
+  
+    public function __construct($ident, $facility = LOG_USER, $level = Logger::DEBUG, $bubble = true)
+    {
+        parent::__construct($level, $bubble);
+
+        // convert textual description of facility to syslog constant
+        if (array_key_exists(strtolower($facility), $this->facilities)) {
+            $facility = $this->facilities[strtolower($facility)];
+        } else if (!in_array($facility, array_values($this->facilities), true)) {
+            throw new \UnexpectedValueException('unknown facility value "'.$facility.'" given');
+        }
+
+        if (!openlog($ident, LOG_NDELAY|LOG_PID, $facility)) {
+            throw new \LogicException('can\'t open syslog for ident "'.$ident.'" and facility "'.$facility.'"'); 
+        }
+    }
+
+    public function write(array $record)
+    {
+        syslog($this->logLevels[$record['level']], (string) $record['message']);
+    }
+
+    public function close()
+    {
+        closelog();
+    }
+}

tests/Monolog/Handler/SyslogHandlerTest.php

@@ -0,0 +1,37 @@
+<?php
+
+/*
+ * This file is part of the Monolog package.
+ *
+ * (c) Jordi Boggiano <j.boggiano@seld.be>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Monolog\Handler;
+
+use Monolog\Logger;
+
+class SyslogHandlerTest extends \PHPUnit_Framework_TestCase
+{
+    public function testConstruct()
+    {
+      $handler = new SyslogHandler('test');
+      $this->assertInstanceOf('Monolog\Handler\SyslogHandler', $handler);
+
+      $handler = new SyslogHandler('test', LOG_LOCAL1);
+      $this->assertInstanceOf('Monolog\Handler\SyslogHandler', $handler);
+
+      $handler = new SyslogHandler('test', 'local1');
+      $this->assertInstanceOf('Monolog\Handler\SyslogHandler', $handler);
+
+    }
+
+    public function testConstructInvalidFacility()
+    {
+      $this->setExpectedException('UnexpectedValueException');
+      $handler = new SyslogHandler('test', 'unknown');
+    }
+
+}