Make terminal_class configurable and provide a manager to detect terminal status on linux systems

jupyter_server/terminal/handlers.py

@@ -2,15 +2,21 @@
 """Tornado handlers for the terminal emulator."""
 # Copyright (c) Jupyter Development Team.
 # Distributed under the terms of the Modified BSD License.
+import json
+
 import terminado
 from tornado import web
 
+from jupyter_server._tz import utcnow
 from ..base.handlers import JupyterHandler
 from ..base.zmqhandlers import WebSocketMixin
-from jupyter_server._tz import utcnow
 
 
 class TermSocket(WebSocketMixin, JupyterHandler, terminado.TermSocket):
+    def initialize(self, *args, **kwargs):
+        super(TermSocket, self).initialize(*args, **kwargs)
+        self._first_stdout = ''
+
     def origin_check(self):
         """Terminado adds redundant origin_check
         Tornado already calls check_origin, so don't do anything here.
@@ -27,13 +33,32 @@ def get(self, *args, **kwargs):
     def on_message(self, message):
         super(TermSocket, self).on_message(message)
         self._update_activity()
+        self._set_state_busy()
 
     def write_message(self, message, binary=False):
         super(TermSocket, self).write_message(message, binary=binary)
-        self._update_activity()
+        message_seg = json.loads(message)
+        if not self._first_stdout and message_seg[0] == 'stdout':
+            # Record the first output to identify the terminal return
+            # It works well for jupyterhub-singleuser and should also work for other debian-based mirrors
+            # fixme: May fail if terminal is not properly separated with ':' or change user after connect
+            #        (Any change to the user, hostname or environment may render it invalid)
+            self._first_stdout = message_seg[1].split(':')[0].lstrip()
+            self.log.debug(f'take "{self._first_stdout}" as terminal returned')
+        if isinstance(message_seg[1], str) and message_seg[1].lstrip().startswith(self._first_stdout):
+            self._set_state_idle()
 
     def _update_activity(self):
         self.application.settings["terminal_last_activity"] = utcnow()
         # terminal may not be around on deletion/cull
         if self.term_name in self.terminal_manager.terminals:
             self.terminal_manager.terminals[self.term_name].last_activity = utcnow()
+
+    def _set_state_busy(self):
+        if self.term_name in self.terminal_manager.terminals:
+            self.terminal_manager.terminals[self.term_name].execution_state = 'busy'
+
+    def _set_state_idle(self):
+        if self.term_name in self.terminal_manager.terminals:
+            self.log.debug('set terminal execution_state as idle')
+            self.terminal_manager.terminals[self.term_name].execution_state = 'idle'

jupyter_server/terminal/terminalmanager.py

@@ -13,9 +13,9 @@
 from traitlets import Integer
 from traitlets.config import LoggingConfigurable
 
-from ..prometheus.metrics import TERMINAL_CURRENTLY_RUNNING_TOTAL
 from jupyter_server._tz import isoformat
 from jupyter_server._tz import utcnow
+from ..prometheus.metrics import TERMINAL_CURRENTLY_RUNNING_TOTAL
 
 
 class TerminalManager(LoggingConfigurable, terminado.NamedTermManager):
@@ -96,6 +96,7 @@ def get_terminal_model(self, name):
         model = {
             "name": name,
             "last_activity": isoformat(term.last_activity),
+            'execution_state': getattr(term, 'execution_state', 'not connected yet')
         }
         return model