Make User not a HasTraits

HasTraits are expensive to instantiate, so make Users as light as possible

Removes immediate instantiation of Spawners during User init. Spawners will only be instantiated while running

jupyterhub/app.py

@@ -1265,9 +1265,11 @@ class JupyterHub(Application):
             orm_user = orm_spawner.user
             user = self.users.add(orm_user)
             self.log.debug("Loading state for %s from db", user.name)
-            for name, spawner in user.spawners.items():
+            for name, orm_spawner in user.orm_spawners.items():
-                f = check_spawner(user, name, spawner)
+                if orm_spawner.server is not None:
-                check_futures.append(f)
+                    spawner = user.spawners[name]
+                    f = check_spawner(user, name, spawner)
+                    check_futures.append(f)
 
         # await checks after submitting them all
         yield gen.multi(check_futures)

jupyterhub/user.py

@@ -127,23 +127,38 @@ class _SpawnerDict(dict):
         return super().__getitem__(key)
 
 
-class User(HasTraits):
+class User:
+    """High-level wrapper around an orm.User object"""
 
-    @default('log')
+    # declare instance attributes
-    def _log_default(self):
+    db = None
-        return app_log
+    orm_user = None
+    log = app_log
+    settings = None
 
-    spawners = None
+    def __init__(self, orm_user, settings=None, **kwargs):
-    settings = Dict()
+        self.orm_user = orm_user
+        self.db = inspect(orm_user).session
+        self.settings = settings or {}
+        for key, attr in kwargs:
+            print('setting', key, attr)
+            setattr(self, key, attr)
 
-    db = Any(allow_none=True)
 
-    @default('db')
+        self.allow_named_servers = self.settings.get('allow_named_servers', False)
-    def _db_default(self):
-        if self.orm_user:
-            return inspect(self.orm_user).session
 
-    orm_user = Any(allow_none=True)
+        self.base_url = self.prefix = url_path_join(
+            self.settings.get('base_url', '/'), 'user', self.escaped_name) + '/'
+
+        self.spawners = _SpawnerDict(self._new_spawner)
+
+    @property
+    def authenticator(self):
+        return self.settings.get('authenticator', None)
+
+    @property
+    def spawner_class(self):
+        return self.settings.get('spawner_class', LocalProcessSpawner)
 
     @gen.coroutine
     def save_auth_state(self, auth_state):
@@ -174,30 +189,6 @@ class User(HasTraits):
                 yield self.save_auth_state(auth_state)
         return auth_state
 
-    @property
-    def authenticator(self):
-        return self.settings.get('authenticator', None)
-
-    @property
-    def spawner_class(self):
-        return self.settings.get('spawner_class', LocalProcessSpawner)
-
-    def __init__(self, orm_user, settings=None, **kwargs):
-        if settings:
-            kwargs['settings'] = settings
-        kwargs['orm_user'] = orm_user
-        super().__init__(**kwargs)
-
-        self.allow_named_servers = self.settings.get('allow_named_servers', False)
-
-        self.base_url = self.prefix = url_path_join(
-            self.settings.get('base_url', '/'), 'user', self.escaped_name) + '/'
-
-        self.spawners = _SpawnerDict(self._new_spawner)
-        # load existing named spawners
-        for name in self.orm_spawners:
-            self.spawners[name] = self._new_spawner(name)
-
     def _new_spawner(self, name, spawner_class=None, **kwargs):
         """Create a new spawner"""
         if spawner_class is None: