#508 add hasLogger method to Monolog\Registry

src/Monolog/Registry.php

@@ -63,6 +63,21 @@ class Registry
         self::$loggers[$name] = $logger;
     }
 
+    /**
+     * Checks if such logging channel exists by name or instance
+     *
+     * @param string|Logger $logger Name or logger instance
+     */
+    public static function hasLogger($logger)
+    {
+        if ($logger instanceof Logger) {
+            $index = array_search($logger, self::$loggers, true);
+            return false !== $index;
+        } else {
+            return isset(self::$loggers[$logger]);
+        }
+    }
+
     /**
      * Removes instance from registry by name or instance
      *