We need a new release desperately

[smac89]

Proposed change

I've been scratching my head for almost a day now wondering why {USERNAME} and {USERID} are not expanded in extra properties. I kept looking at the code in this repo, and tracing all the steps and everything suggests that those variables should be expanded, yet when I run my jupyterhub, after the first user is created, any subsequent user receives 500 server error because the runtime directory created is not expanded, and the unit attempts to use the directory of another.

I see that the last release was in 2020, but the commit that allows expanding the variables was done in 2021.

Alternative options

Make a partial release which only includes this one commit

Who would use this feature?

Anyone who has read the readme recently

(Optional): Suggest a solution

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[smac89]

If it helps, this is how I use unit_extra_properties:

c.SystemdSpawner.unit_extra_properties = {
    "RuntimeDirectory": os.path.join(
        *(
            os.getenv("RUNTIME_DIRECTORY") # RUNTIME_DIRECTORY comes from parent's process when setting its' RuntimeDirectory
            .split(os.path.pathsep)[0]
            .split(os.path.sep)[2:]
        ),
        '{USERNAME}',
        # TODO: Would be nice to use {USERID} or {USERNAME} here...
    ),
    ...
}

---

Just as I posted this, I discovered a workaround, using pre_spawn_hook:

def load_course_material(spawner: "systemdspawner.SystemdSpawner") -> None:
    from subprocess import check_call

    # workaround until https://github.com/jupyterhub/systemdspawner/issues/93 is resolved
    for prop, value in spawner.unit_extra_properties.items():
        spawner.unit_extra_properties[prop] = spawner._expand_user_vars(value)

    # ...

c.Spawner.pre_spawn_hook = load_course_material

Now I can have all my users able to login and work at the same time!

[yuvipanda]

Thanks for the ping, @smac89! I've just released v0.16 with that PR included. Apologies for the delay, and sorry about the frustration it caused. I'm glad you were able to find a workaround though!