Extract out kernels

jupyter_server/base/handlers.py

@@ -322,6 +322,14 @@ def contents_manager(self):
 
     @property
     def session_manager(self):
+        if "session_manager" not in self.settings:
+            self.settings["session_manager"] = self.settings["session_manager_class"](
+                parent=self.serverapp,
+                log=self.settings["log"],
+                kernel_manager=self.settings["kernel_manager"],
+                contents_manager=self.contents_manager,
+            )
+
         return self.settings["session_manager"]
 
     @property

jupyter_server/base/zmqhandlers.py

@@ -2,15 +2,15 @@
 # Raise a warning that this module is deprecated.
 import warnings
 
-from tornado.websocket import WebSocketHandler
-
-from jupyter_server.base.websocket import WebSocketMixin
-from jupyter_server.services.kernels.connection.base import (
+from jupyter_server_kernels.kernels.connection.base import (
     deserialize_binary_message,
     deserialize_msg_from_ws_v1,
     serialize_binary_message,
     serialize_msg_to_ws_v1,
 )
+from tornado.websocket import WebSocketHandler
+
+from jupyter_server.base.websocket import WebSocketMixin
 
 warnings.warn(
     "jupyter_server.base.zmqhandlers module is deprecated in Jupyter Server 2.0",

jupyter_server/gateway/managers.py

@@ -16,13 +16,13 @@
 from jupyter_client.kernelspec import KernelSpecManager
 from jupyter_client.manager import AsyncKernelManager
 from jupyter_client.managerabc import KernelManagerABC
+from jupyter_server_kernels.kernels.kernelmanager import AsyncMappingKernelManager
+from jupyter_server_kernels.sessions.sessionmanager import SessionManager
 from tornado import web
 from tornado.escape import json_decode, json_encode, url_escape, utf8
 from traitlets import DottedObjectName, Instance, Type, default
 
 from .._tz import UTC
-from ..services.kernels.kernelmanager import AsyncMappingKernelManager
-from ..services.sessions.sessionmanager import SessionManager
 from ..utils import ensure_async, url_path_join
 from .gateway_client import GatewayClient, gateway_request