Migrate start-notebook & start-singleuser to python

[yuvipanda]

Based on

Stop using bash, haha 👍

from #1532.

If there's more apetite for this, I'll try to migrate start.sh and start-singleuser.sh as well - I think they should all be merged together. We can remove the .sh suffixes for accuracy, and keep symlinks in so old config still works. Since the shebang is what is used to launch the correct interpreter, the .sh doesn't matter.

Will help fix #1532, as I believe all those things are going to be easier to do from python than bash

TODO

• Add .py extensions to the script
• Add shim .sh files that just redirect us back
• Document these .sh scripts

[yuvipanda]

@mathbunnyru I wanted to ask if there's apetite for this kinda change before I put more work into this :)

[yuvipanda]

I'll take a look at the test failures if this kinda migration is acceptable! I'm sure I can sort those out if needed.

[mathbunnyru]

I like this PR a lot, just a few thoughts about the implementation:

1. Let's add the .py extension to the added start-like scripts. It doesn't change much, but some utils (maybe pre-commit hooks) and editors definitely work better (at least not worse).
2. Instead of symlinking to keep compatibility, I propose having simple shell files, which first echo a warning that calling is file is deprecated and then simply pass all the params to the corresponding .py file. This way we will be able to first replace a warning with a hard error in a few months and then completely delete the .sh files.
3. Let's also document the warning about calling old .sh start scripts.
4. I really hope you will have the courage to deal with start.sh when we merge this PR 🙂

Overall, great PR, thank you!

[mathbunnyru]

I updated your branch (to make sure we test latest versions of everything).

[yuvipanda]

Glad to hear you like it, @mathbunnyru! I've addressed all the points you mentioned and I think this is ready for review now.

I do personally prefer leaving out the .py suffix, but am alright leaving it in. I find that most tools are ok looking at the shebang for detection in those cases, but I'm sure that's not 100% of them.

I'm definitely interested in tackling start.sh as well! I actually wrote https://github.com/yuvipanda/jupyterhub-roothooks/ a while ago that provides some part of that functionality, so there's gonna be stuff for me to steal from there. I also spent today picking up a plan to replicate as exactly as possible bash's source semantics in python and I think I've a path there.

My goal would be to do this in such a way that all the existing tests pass, so no new functionality.

[yuvipanda]

@mathbunnyru hah, we clashed as I was just about to rebase :)

[mathbunnyru]

I appreciate it that you added comments to this file! I'm sure it will help future contributors to understand this file faster.

[yuvipanda]

@mathbunnyru you're welcome :)

[manics]

I'm definitely interested in tackling start.sh as well! I actually wrote https://github.com/yuvipanda/jupyterhub-roothooks/ a while ago that provides some part of that functionality, so there's gonna be stuff for me to steal from there. I also spent today picking up a plan to replicate as exactly as possible bash's source semantics in python and I think I've a path there.

If you're modifying the behaviour of the start scripts #1528 might fit in too.

[yuvipanda]

@manics I'm probably going to just try do a verbatim port, and leave the behavior modification to others in the future. Hopefully the fact that it's in python and not bash will make that easier.

[yuvipanda]

Yay, thank you for the quick review and merge, @mathbunnyru. And for the long set of tests that made this easy