Add log writer PhpWriter

refs #11652

library/Icinga/Application/Logger/Writer/PhpWriter.php

@@ -0,0 +1,39 @@
+<?php
+/* Icinga Web 2 | (c) 2016 Icinga Development Team | GPLv2+ */
+
+namespace Icinga\Application\Logger\Writer;
+
+use Icinga\Application\Logger;
+use Icinga\Application\Logger\LogWriter;
+use Icinga\Data\ConfigObject;
+use Icinga\Exception\NotWritableError;
+
+/**
+ * Log to the webserver log, a file or syslog
+ *
+ * @see https://secure.php.net/manual/en/errorfunc.configuration.php#ini.error-log
+ */
+class PhpWriter extends LogWriter
+{
+    /**
+     * Prefix to prepend to each message
+     *
+     * @var string
+     */
+    protected $ident;
+
+    public function __construct(ConfigObject $config)
+    {
+        parent::__construct($config);
+        $this->ident = $config->get('application', 'icingaweb2');
+    }
+
+    public function log($severity, $message)
+    {
+        if (ini_get('error_log') === 'syslog') {
+            $message = str_replace("\n", '    ', $message);
+        }
+
+        error_log($this->ident . ': ' . Logger::$levels[$severity] . ' - ' . $message);
+    }
+}