Extract method loader()

radicale/utils.py

@@ -0,0 +1,36 @@
+# This file is part of Radicale Server - Calendar Server
+# Copyright © 2014 Jean-Marc Martins
+# Copyright © 2012-2017 Guillaume Ayoub
+# Copyright © 2017-2018 Unrud <unrud@outlook.com>
+#
+# This library 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 3 of the License, or
+# (at your option) any later version.
+#
+# This library 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 Radicale.  If not, see <http://www.gnu.org/licenses/>.
+
+from importlib import import_module
+
+from radicale.log import logger
+
+
+def loader(internal_types, module_name, class_name, configuration):
+    type_ = configuration.get(module_name, "type")
+    if type_ in internal_types:
+        module = "radicale.%s.%s" % (module_name, type_)
+    else:
+        module = type_
+    try:
+        class_ = getattr(import_module(module), class_name)
+    except Exception as e:
+        raise RuntimeError("Failed to load %s module %r: %s" %
+                           (module_name, module, e)) from e
+    logger.info("%s type is %r", module_name, module)
+    return class_(configuration)