No attribute `_start_future`

KubeSpawner object has no attribute _start_future

I get this error in my hub log from time to time. Note that the users will be redirected instantaneously to the progress page, which is a new thing.

This does not affect my deployment as far as I know, only the logs, which causes some raised eyebrows.

[W 2018-09-18 17:48:06.542 JupyterHub base:714] User erik.sundell is slow to start (timeout=0)
[I 2018-09-18 17:48:06.544 JupyterHub base:1056] erik.sundell is pending spawn
[I 2018-09-18 17:48:06.548 JupyterHub log:158] 200 GET /hub/user/erik.sundell/ ([e-mail]) 81.35ms
[E 2018-09-18 17:48:06.826 JupyterHub web:1670] Uncaught exception GET /hub/api/users/erik.sundell/server/progress (10.132.0.14)
    HTTPServerRequest(protocol='https', host='hub.example.com', method='GET', uri='/hub/api/users/erik.sundell/server/progress', version='HTTP/1.1', remote_ip='10.132.0.14')
    Traceback (most recent call last):
      File "/usr/local/lib/python3.6/dist-packages/tornado/web.py", line 1592, in _execute
        result = yield result
      File "/usr/local/lib/python3.6/dist-packages/jupyterhub/apihandlers/users.py", line 496, in get
        async for event in events:
      File "/usr/local/lib/python3.6/dist-packages/async_generator/_impl.py", line 366, in step
        return await ANextIter(self._it, start_fn, *args)
      File "/usr/local/lib/python3.6/dist-packages/async_generator/_impl.py", line 199, in __next__
        return self._invoke(self._it.__next__)
      File "/usr/local/lib/python3.6/dist-packages/async_generator/_impl.py", line 209, in _invoke
        result = fn(*args)
      File "/usr/local/lib/python3.6/dist-packages/jupyterhub/utils.py", line 495, in iterate_until
        await yield_(item_future.result())
      File "/usr/local/lib/python3.6/dist-packages/async_generator/_impl.py", line 366, in step
        return await ANextIter(self._it, start_fn, *args)
      File "/usr/local/lib/python3.6/dist-packages/async_generator/_impl.py", line 197, in __next__
        return self._invoke(first_fn, *first_args)
      File "/usr/local/lib/python3.6/dist-packages/async_generator/_impl.py", line 209, in _invoke
        result = fn(*args)
      File "/usr/local/lib/python3.6/dist-packages/jupyterhub/spawner.py", line 745, in _generate_progress
        async for event in progress:
      File "/usr/local/lib/python3.6/dist-packages/async_generator/_impl.py", line 366, in step
        return await ANextIter(self._it, start_fn, *args)
      File "/usr/local/lib/python3.6/dist-packages/async_generator/_impl.py", line 197, in __next__
        return self._invoke(first_fn, *first_args)
      File "/usr/local/lib/python3.6/dist-packages/async_generator/_impl.py", line 209, in _invoke
        result = fn(*args)
      File "/usr/local/lib/python3.6/dist-packages/kubespawner/spawner.py", line 1526, in progress
        start_future = self._start_future
    AttributeError: 'KubeSpawner' object has no attribute '_start_future'
    
[E 2018-09-18 17:48:06.827 JupyterHub web:1091] Cannot send error response after headers written
[I 2018-09-18 17:48:06.828 JupyterHub log:158] 200 GET /hub/api/users/erik.sundell/server/progress ([e-mail]) 126.98ms
[I 2018-09-18 17:48:06.833 JupyterHub spawner:1671] PVC claim-erik-2esundell already exists, so did not create new pvc.
[I 2018-09-18 17:48:27.785 JupyterHub log:158] 200 GET /hub/api (@xxx.xxx.xxx.xxx) 1.21ms
[I 2018-09-18 17:48:30.894 JupyterHub base:628] User erik.sundell took 24.408 seconds to start
[I 2018-09-18 17:48:30.895 JupyterHub proxy:242] Adding user erik.sundell to proxy /user/erik.sundell/ => http://xxx.xxx.xxx.xxx:8888
[I 2018-09-18 17:48:30.898 JupyterHub users:510] Server erik.sundell is ready
[I 2018-09-18 17:48:30.899 JupyterHub log:158] 200 GET /hub/api/users/erik.sundell/server/progress ([e-mail]) 21028.49ms
[I 2018-09-18 17:48:30.960 JupyterHub log:158] 302 GET /hub/user/erik.sundell/ -> /user/erik.sundell/?redirects=1 ([e-mail]) 12.06ms
[I 2018-09-18 17:48:31.113 JupyterHub log:158] 302 GET /hub/api/oauth2/authorize?client_id=jupyterhub-user-erik.sundell&redirect_uri=%2Fuser%2Ferik.sundell%2Foauth_callback&response_type=code&state=[secret] -> /user/erik.sundell/oauth_callback?code=[secret]&state=[secret] ([e-mail]) 28.16ms

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@minrk wrote

This is interesting! It means the progress API is being called before start. I would think this is a bug in the timing of method calls, but it’s likely that start is “scheduled immediately” rather than kicked-off in a synchronous way that would ensure it’s actually called before progress. We should wait until _start_future is defined in progress.

[jabbera]

There is an open PR waiting to be merged that would resolve this: https://github.com/jupyterhub/kubespawner/pull/511

[athornton]

I never did, but internally we’re still not quite at current JupyterHub.