bump jupyterhub to 2.*

[raybellwaves]

• Add / update documentation
• Add tests

Firstly, does it still work?
Secondly, any reason why not?

[manics]

I think we'll need to resolve #724 since this is a breaking change

[jtpio]

This will fix #818

[manics]

The hub environment is updated separately from the user environment so this also needs an update:

the-littlest-jupyterhub/tljh/installer.py

Line 124 in 121b4c7

"jupyterhub==1.*",

The JupyterHub DB should be upgraded automatically if needed so no need to worry about running jupyterhub upgrade-db:

the-littlest-jupyterhub/tljh/systemd-units/jupyterhub.service

Line 20 in 121b4c7

ExecStart={python_interpreter_path} -m jupyterhub.app -f {jupyterhub_config_path} --upgrade-db

Though I've just tried a manual update of JupyterHub and it's failing:

Jun 17 17:38:41 ubuntu2004.localdomain python3[4460]: [E 2022-06-17 17:38:41.526 JupyterHub app:3297]
Jun 17 17:38:41 ubuntu2004.localdomain python3[4460]:     Traceback (most recent call last):
Jun 17 17:38:41 ubuntu2004.localdomain python3[4460]:       File "/opt/tljh/hub/lib/python3.8/site-packages/jupyterhub/app.py", line 3294, in launch_instance_async
Jun 17 17:38:41 ubuntu2004.localdomain python3[4460]:         await self.initialize(argv)
Jun 17 17:38:41 ubuntu2004.localdomain python3[4460]:       File "/opt/tljh/hub/lib/python3.8/site-packages/jupyterhub/app.py", line 2813, in initialize
Jun 17 17:38:41 ubuntu2004.localdomain python3[4460]:         self.init_db()
Jun 17 17:38:41 ubuntu2004.localdomain python3[4460]:       File "/opt/tljh/hub/lib/python3.8/site-packages/jupyterhub/app.py", line 1777, in init_db
Jun 17 17:38:41 ubuntu2004.localdomain python3[4460]:         dbutil.upgrade_if_needed(self.db_url, log=self.log)
Jun 17 17:38:41 ubuntu2004.localdomain python3[4460]:       File "/opt/tljh/hub/lib/python3.8/site-packages/jupyterhub/dbutil.py", line 135, in upgrade_if_needed
Jun 17 17:38:41 ubuntu2004.localdomain python3[4460]:         upgrade(db_url)
Jun 17 17:38:41 ubuntu2004.localdomain python3[4460]:       File "/opt/tljh/hub/lib/python3.8/site-packages/jupyterhub/dbutil.py", line 84, in upgrade
Jun 17 17:38:41 ubuntu2004.localdomain python3[4460]:         check_call(['alembic', '-c', alembic_ini, 'upgrade', revision])
Jun 17 17:38:41 ubuntu2004.localdomain python3[4460]:       File "/usr/lib/python3.8/subprocess.py", line 359, in check_call
Jun 17 17:38:41 ubuntu2004.localdomain python3[4460]:         retcode = call(*popenargs, **kwargs)
Jun 17 17:38:41 ubuntu2004.localdomain python3[4460]:       File "/usr/lib/python3.8/subprocess.py", line 340, in call
Jun 17 17:38:41 ubuntu2004.localdomain python3[4460]:         with Popen(*popenargs, **kwargs) as p:
Jun 17 17:38:41 ubuntu2004.localdomain python3[4460]:       File "/usr/lib/python3.8/subprocess.py", line 858, in __init__
Jun 17 17:38:41 ubuntu2004.localdomain python3[4460]:         self._execute_child(args, executable, preexec_fn, close_fds,
Jun 17 17:38:41 ubuntu2004.localdomain python3[4460]:       File "/usr/lib/python3.8/subprocess.py", line 1704, in _execute_child
Jun 17 17:38:41 ubuntu2004.localdomain python3[4460]:         raise child_exception_type(errno_num, err_msg, err_filename)
Jun 17 17:38:41 ubuntu2004.localdomain python3[4460]:     FileNotFoundError: [Errno 2] No such file or directory: 'alembic'
Jun 17 17:38:41 ubuntu2004.localdomain python3[4460]:     
Jun 17 17:38:41 ubuntu2004.localdomain systemd[1]: jupyterhub.service: Main process exited, code=exited, status=1/FAILURE
Jun 17 17:38:41 ubuntu2004.localdomain systemd[1]: jupyterhub.service: Failed with result 'exit-code'.
Jun 17 17:38:42 ubuntu2004.localdomain systemd[1]: jupyterhub.service: Scheduled restart job, restart counter is at 5.
Jun 17 17:38:42 ubuntu2004.localdomain systemd[1]: Stopped jupyterhub.service.
Jun 17 17:38:42 ubuntu2004.localdomain systemd[1]: jupyterhub.service: Start request repeated too quickly.
Jun 17 17:38:42 ubuntu2004.localdomain systemd[1]: jupyterhub.service: Failed with result 'exit-code'.
Jun 17 17:38:42 ubuntu2004.localdomain systemd[1]: Failed to start jupyterhub.service.

/opt/tljh/hub/bin/alembic exists, so maybe /opt/tljh/hub/bin needs to be added to PATH in jupyterhub.service?

[consideRatio]

• Closed by update: jupyterhub 3, oauthenticator 15, systemdspawner 0.17 (user env: ipywidgets 8) #842