Merge pull request #2473 from matrix-org/dbkr/factor_out_module_loading

Factor out module loading to a separate place

synapse/config/password_auth_providers.py

@@ -15,13 +15,15 @@
 
 from ._base import Config, ConfigError
 
-import importlib
+from synapse.util.module_loader import load_module
 
 
 class PasswordAuthProviderConfig(Config):
     def read_config(self, config):
         self.password_providers = []
 
+        provider_config = None
+
         # We want to be backwards compatible with the old `ldap_config`
         # param.
         ldap_config = config.get("ldap_config", {})
@@ -38,19 +40,15 @@ class PasswordAuthProviderConfig(Config):
             if provider['module'] == "synapse.util.ldap_auth_provider.LdapAuthProvider":
                 from ldap_auth_provider import LdapAuthProvider
                 provider_class = LdapAuthProvider
-            else:
-                # We need to import the module, and then pick the class out of
-                # that, so we split based on the last dot.
-                module, clz = provider['module'].rsplit(".", 1)
-                module = importlib.import_module(module)
-                provider_class = getattr(module, clz)
-
                 try:
                     provider_config = provider_class.parse_config(provider["config"])
                 except Exception as e:
                     raise ConfigError(
                         "Failed to parse config for %r: %r" % (provider['module'], e)
                     )
+            else:
+                (provider_class, provider_config) = load_module(provider)
+
             self.password_providers.append((provider_class, provider_config))
 
     def default_config(self, **kwargs):

synapse/util/module_loader.py

@@ -0,0 +1,41 @@
+# -*- coding: utf-8 -*-
+# Copyright 2017 New Vector Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import importlib
+
+from synapse.config._base import ConfigError
+
+def load_module(provider):
+    """ Loads a module with its config
+    Take a dict with keys 'module' (the module name) and 'config'
+    (the config dict).
+
+    Returns
+        Tuple of (provider class, parsed config object)
+    """
+    # We need to import the module, and then pick the class out of
+    # that, so we split based on the last dot.
+    module, clz = provider['module'].rsplit(".", 1)
+    module = importlib.import_module(module)
+    provider_class = getattr(module, clz)
+
+    try:
+        provider_config = provider_class.parse_config(provider["config"])
+    except Exception as e:
+        raise ConfigError(
+            "Failed to parse config for %r: %r" % (provider['module'], e)
+        )
+
+    return provider_class, provider_config