Standalone mode set by extension authors

jupyter_server/extension/application.py

@@ -72,6 +72,8 @@ class ExtensionApp(JupyterApp):
         class method. This method can be set as a entry_point in 
         the extensions setup.py
     """
+    load_other_extensions = True
+
     # Name of the extension
     extension_name = Unicode(
         "",
@@ -152,8 +154,8 @@ def _prepare_config(self):
         the object to the webapp's settings as `<extension_name>_config`.  
         """
         traits = self.class_own_traits().keys()
-        self.config = Config({t: getattr(self, t) for t in traits})
-        self.settings['{}_config'.format(self.extension_name)] = self.config
+        self.extension_config = Config({t: getattr(self, t) for t in traits})
+        self.settings['{}_config'.format(self.extension_name)] = self.extension_config
 
     def _prepare_settings(self):
         # Make webapp settings accessible to initialize_settings method
@@ -220,14 +222,14 @@ def _prepare_templates(self):
         self.initialize_templates()
 
     @staticmethod
-    def initialize_server(argv=[], **kwargs):
+    def initialize_server(argv=[], load_other_extensions=True, **kwargs):
         """Get an instance of the Jupyter Server."""
         # Get a jupyter server instance
         serverapp = ServerApp(**kwargs)
         # Initialize ServerApp config.
         # Parses the command line looking for 
         # ServerApp configuration.
-        serverapp.initialize(argv=argv)
+        serverapp.initialize(argv=argv, load_extensions=load_other_extensions)
         return serverapp
 
     def initialize(self, serverapp, argv=[]):
@@ -279,7 +281,6 @@ def load_jupyter_server_extension(cls, serverapp, argv=[], **kwargs):
         # Configure and initialize extension.
         extension = cls()
         extension.initialize(serverapp, argv=argv)
-
         return extension
 
     @classmethod
@@ -290,7 +291,6 @@ def _prepare_launch(cls, serverapp, argv=[], **kwargs):
         """
         # Load the extension
         extension = cls.load_jupyter_server_extension(serverapp, argv=argv, **kwargs)
-
         # Start the browser at this extensions default_url, unless user
         # configures ServerApp.default_url on command line.
         try:
@@ -313,13 +313,22 @@ def launch_instance(cls, argv=None, **kwargs):
         # arguments trigger actions from the extension not the server.
         _preparse_command_line(cls)
         # Handle arguments.
-        if argv is not None:
+        if argv is None:
             args = sys.argv[1:]  # slice out extension config.
         else:
             args = []
-
         # Get a jupyter server instance.
-        serverapp = cls.initialize_server(argv=args)
+        serverapp = cls.initialize_server(
+            argv=args, 
+            load_other_extensions=cls.load_other_extensions
+        )
+        # Log if extension is blocking other extensions from loading.
+        if not cls.load_other_extensions:
+            serverapp.log.info(
+                "{ext_name} is running without loading "
+                "other extensions.".format(ext_name=cls.extension_name)
+            )
+
         extension = cls._prepare_launch(serverapp, argv=args, **kwargs)
         # Start the ioloop.
         extension.start_server()

jupyter_server/extension/handler.py

@@ -19,6 +19,10 @@ def initialize(self, extension_name):
     def config(self):
         return self.settings["{}_config".format(self.extension_name)]
 
+    @property
+    def server_config(self):
+        return self.settings["config"]
+
     @property
     def static_url_prefix(self):
         return "/static/{extension_name}/".format(

jupyter_server/serverapp.py

@@ -1415,6 +1415,10 @@ def init_server_extensions(self):
                     func = getattr(mod, 'load_jupyter_server_extension', None)
                     if func is not None:
                         func(self)
+                        # Add debug log for loaded extensions.
+                        self.log.debug("%s is enabled and loaded." % modulename)
+                    else:
+                        self.log.warning("%s is enabled but no `load_jupyter_server_extension` function was found")
                 except Exception:
                     if self.reraise_server_extension_failures:
                         raise
@@ -1459,7 +1463,7 @@ def init_shutdown_no_activity(self):
             pc.start()
 
     @catch_config_error
-    def initialize(self, argv=None):
+    def initialize(self, argv=None, load_extensions=True):
         super(ServerApp, self).initialize(argv)
         self.init_logging()
         if self._dispatching:
@@ -1469,7 +1473,8 @@ def initialize(self, argv=None):
         self.init_webapp()
         self.init_terminals()
         self.init_signal()
-        self.init_server_extensions()
+        if load_extensions:
+            self.init_server_extensions()
         self.init_mime_overrides()
         self.init_shutdown_no_activity()