surface config.d nbserver_extensions to the NotebookApp config object

- separates nbserver_extension config loading into new
init_server_extension_config method
- adds init_server_extension_config to the initialize funciton before
the init_webapp call
- adds nbserver_extension configuration found in config.d files (by the
BaseJSONConfigLoader) to both the underlying NotebookApp config object
and the self.nbserver_extensions value
- makes self.nbserver_extensions the canonical location for identifying
all nbserver_extensions rather than temporary extensions variable

Author: mpacer

jupyter_server/serverapp.py

@@ -1442,15 +1442,13 @@ def init_components(self):
         # TODO: this should still check, but now we use bower, not git submodule
         pass
 
-    def init_server_extensions(self):
-        """Load any extensions specified by config.
-
-        Import the module, then call the load_jupyter_server_extension function,
-        if one exists.
+    def init_server_extension_config(self):
+        """Consolidate server extensions specified by all configs.
 
+        The resulting list is stored on self.nbserver_extensions and updates config object.
+        
         The extension API is experimental, and may change in future releases.
         """
-
         # Load server extensions with ConfigManager.
         # This enables merging on keys, which we want for extension enabling.
         # Regular config loading only merges at the class level,
@@ -1462,15 +1460,21 @@ def init_server_extensions(self):
         manager = ConfigManager(read_config_path=config_path)
         section = manager.get(self.config_file_name)
         extensions = section.get('ServerApp', {}).get('jpserver_extensions', {})
+        
+        for modulename, enabled in sorted(extensions.items()):
+            if modulename not in self.jpserver_extensions:
+                self.config.ServerApp.jpserver_extensions.update({modulename: enabled})
+                self.jpserver_extensions.update({modulename: enabled})
 
-        for modulename, enabled in self.jpserver_extensions.items():
-            if modulename not in extensions:
-                # not present in `extensions` means it comes from Python config,
-                # so we need to add it.
-                # Otherwise, trust ConfigManager to have loaded it.
-                extensions[modulename] = enabled
+    def init_server_extensions(self):
+        """Load any extensions specified by config.
 
-        for modulename, enabled in sorted(extensions.items()):
+        Import the module, then call the load_jupyter_server_extension function,
+        if one exists.
+        
+        The extension API is experimental, and may change in future releases.
+        """
+        for modulename, enabled in sorted(self.jpserver_extensions.items()):
             if enabled:
                 try:
                     mod = importlib.import_module(modulename)
@@ -1538,6 +1542,7 @@ def initialize(self, argv=None, load_extensions=True):
         if self._dispatching:
             return
         self.init_configurables()
+        self.init_server_extension_config()
         self.init_components()
         self.init_webapp()
         self.init_terminals()

jupyter_server/tests/test_extensions.py

@@ -137,7 +137,12 @@ def test_merge_config(self):
         toggle_serverextension_python('mockext_both', enabled=True, user=False)
         toggle_serverextension_python('mockext_both', enabled=False, user=True)
 
+<<<<<<< HEAD:jupyter_server/tests/test_extensions.py
         app = ServerApp(jpserver_extensions={'mockext_py': True})
+=======
+        app = NotebookApp(nbserver_extensions={'mockext_py': True})
+        app.init_server_extension_config()
+>>>>>>> 134c8b6c0... surface config.d nbserver_extensions to the NotebookApp config object:notebook/tests/test_serverextensions.py
         app.init_server_extensions()
 
         assert mock_user.loaded