Don't assume empty state means not running #824
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Some Spawners may not need state, and they should be allowed to resume on Hub restart as well. Adds some detail about when .poll may be called and how it should behave in less obvious circumstances
| @@ -351,6 +351,20 @@ def poll(self): | |||
| """Check if the single-user process is running | |||
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| return None if it is, an exit status (0 if unknown) if it is not. | |||
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returns:
None, if single-user process is running.
Exit status (0 if unknown), if it is not running.
State transitions, behavior, and return response:
| If the Spawner has not finished starting, | ||
| it should behave as if it is running (status=None). | ||
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| Assumptions about poll and when it can be called: |
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Design assumptions about when `poll` may be called:
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| Assumptions about poll and when it can be called: | ||
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| - poll may be called before start when state is loaded on Hub restart. |
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- On Hub restart: 'poll' may be called before 'start' when state is loaded on Hub restart.
'poll' should return exit status 0 (unknown) if the Spawner has not been
initialized via 'load_state' or 'start'.
- If `.start()` is async: 'poll' may be called during any yielded portions of the 'start' process.
'poll' should return None when 'start' is yielded, indicating that the
'start' process has not yet exited (completed?).
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Spacing is a bit wonky above, but you get the gist ;-)
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Thanks @minrk. Changes look great. I'm going to go ahead and merge. We can always iterate if @yuvipanda's report or community uncover anything. |
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I worked around this problem in kubernetes spawner, but I think systemd On Thu, Oct 27, 2016 at 8:34 AM, Carol Willing notifications@github.com
Yuvi Panda T |
Don't assume empty state means not running
Some Spawners may not need state, and they should be allowed to resume on Hub restart as well.
Adds some detail about when .poll may be called and how it should behave in less obvious circumstances.
closes #819
cc @willingc for docs, @yuvipanda for report