[feature] add host processor

src/Monolog/Processor/HostnameProcessor.php

@@ -0,0 +1,34 @@
+<?php declare(strict_types=1);
+
+/*
+ * 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\Processor;
+
+use Monolog\Logger;
+
+/**
+ * Injects value of gethostname in all records
+ */
+class HostnameProcessor
+{
+    private static $host;
+
+    public function __construct()
+    {
+        self::$host = (string) gethostname();
+    }
+
+    public function __invoke(array $record): array
+    {
+        $record['extra']['hostname'] = self::$host;
+
+        return $record;
+    }
+}