Add post-spawn hook

examples/bootstrap-script/README.md

@@ -25,6 +25,9 @@ Another use would be to copy initial content, such as tutorial files or referenc
 You can define your own bootstrap process by implementing a `pre_spawn_hook` on any spawner.
 The Spawner itself is passed as parameter to your hook and you can easily get the contextual information out of the spawning process. 
 
+Similarly, there may be cases where you would like to clean up after a spawner stops.
+You may implement a `post_spawn_hook` that is always executed after the spawner stops.
+
 If you implement a hook, make sure that it is *idempotent*. It will be executed every time
 a notebook server is spawned to the user. That means you should somehow
 ensure that things which should run only once are not running again and again.

examples/bootstrap-script/jupyterhub_config.py

@@ -2,6 +2,7 @@
 # create a directory for the user before the spawner starts
 
 import os
+import shutil
 def create_dir_hook(spawner):
     username = spawner.user.name # get the username
     volume_path = os.path.join('/volumes/jupyterhub', username)
@@ -10,8 +11,15 @@ def create_dir_hook(spawner):
         # now do whatever you think your user needs
         # ...
 
-# attach the hook function to the spawner
+def clean_dir_hook(spawner):
+    username = spawner.user.name # get the username
+    temp_path = os.path.join('/volumes/jupyterhub', username, 'temp')
+    if os.path.exists(temp_path) and os.path.isdir(temp_path):
+        shutil.rmtree(temp_path)
+
+# attach the hook functions to the spawner
 c.Spawner.pre_spawn_hook = create_dir_hook
+c.Spawner.post_spawn_hook = clean_dir_hook
 
 # Use the DockerSpawner to serve your users' notebooks
 c.JupyterHub.spawner_class = 'dockerspawner.DockerSpawner'

jupyterhub/spawner.py

@@ -515,6 +515,15 @@ class Spawner(LoggingConfigurable):
         """
     ).tag(config=True)
 
+    post_spawn_hook = Any(
+        help="""
+        An optional hook function that you can implement to do work after
+        the spawner stops.
+
+        This can be set independent of any concrete spawner implementation.
+        """
+    ).tag(config=True)
+
     def load_state(self, state):
         """Restore state of spawner from database.
 
@@ -692,6 +701,13 @@ class Spawner(LoggingConfigurable):
         if self.pre_spawn_hook:
             return self.pre_spawn_hook(self)
 
+    def run_post_spawn_hook(self):
+        """Run the post_spawn_hook if defined"""
+        try:
+            return self.post_spawn_hook(self)
+        except Exception:
+            self.log.exception("post_spawn_hook failed with exception: %s", self)
+
     @property
     def _progress_url(self):
         return self.user.progress_url(self.name)

jupyterhub/user.py

@@ -559,6 +559,8 @@ class User:
         finally:
             spawner.orm_spawner.started = None
             self.db.commit()
+            # trigger post-spawner hook
+            await maybe_future(spawner.run_post_spawn_hook())
             # trigger post-spawner hook on authenticator
             auth = spawner.authenticator
             try: