Support idle culler debug logging

[manics]

Proposed change

The Z2jh idle culler does not support debug logging:

zero-to-jupyterhub-k8s/jupyterhub/files/hub/jupyterhub_config.py

Lines 356 to 391 in b407b54

	cull_cmd = ["python3", "-m", "jupyterhub_idle_culler"]
	base_url = c.JupyterHub.get("base_url", "/")
	cull_cmd.append("--url=http://localhost:8081" + url_path_join(base_url, "hub/api"))
	cull_timeout = get_config("cull.timeout")
	if cull_timeout:
	cull_cmd.append(f"--timeout={cull_timeout}")
	cull_every = get_config("cull.every")
	if cull_every:
	cull_cmd.append(f"--cull-every={cull_every}")
	cull_concurrency = get_config("cull.concurrency")
	if cull_concurrency:
	cull_cmd.append(f"--concurrency={cull_concurrency}")
	if get_config("cull.users"):
	cull_cmd.append("--cull-users")
	jupyterhub_idle_culler_role["scopes"].append("admin:users")
	if not get_config("cull.adminUsers"):
	cull_cmd.append("--cull-admin-users=false")
	if get_config("cull.removeNamedServers"):
	cull_cmd.append("--remove-named-servers")
	cull_max_age = get_config("cull.maxAge")
	if cull_max_age:
	cull_cmd.append(f"--max-age={cull_max_age}")
	c.JupyterHub.services.append(
	{
	"name": "jupyterhub-idle-culler",
	"command": cull_cmd,
	}
	)

For instance, it should be possible to enable debug logs using Tornado's built-in option --logging=debug, which could be passed when debug.enabled is set in the chart.

I noticed this whilst answering https://discourse.jupyter.org/t/idle-culler-not-culling/21301/3

Alternative options

• Add a new option to control idle culler logging
• Allowing an array of additional command line args to be passed
• Allow the entire idle culler command to be overridden

Who would use this feature?

Admins wanting to debug the culling in z2jh.

(Optional): Suggest a solution

See above