Voila doesn't render notebooks with JupyterHub and BatchSpawner

Bug description

Dear all, I am experiencing issues while running Voila from a Jupyter session started via batchspawner. I suspect a configuration / setup problem but alone I can't figure out what I can try to troubleshoot.

In my setup, Voila runs perfectly fine

if voila or jupyterlab are started directly
if voila or jupyterlab are accessed via jupyterHub using the SimpleLocalProcessSpawner spawner

Unfortunately with BatchSpawner, the Voila landing page starts, notebooks are open but the voila render doesn't start at all.

I can't find Jupyter or Javascript console logs to troubleshoot.

Does anyone have a suggestion for troubleshooting / configuration change?

Many thanks, Gianluca

Your personal set up

My configuration is the following:

jupyterhub 1.3.0
jupyterlab 2.2.9
jupyter_server 1.2.1
batchspawner 1.1.0.dev0

This is a minimalistic jupyterhub_config.py file to reproduce this behaviour:

from traitlets import Unicode
from jupyterhub.spawner import SimpleLocalProcessSpawner
import batchspawner

IP = os.getenv("HOSTNAME")
c.JupyterHub.ip = IP
c.JupyterHub.hub_ip = IP
c.JupyterHub.port = 26000
c.JupyterHub.hub_port = 26001
c.ConfigurableHTTPProxy.api_url = f"http://{IP}:26002"
c.Spawner.environment = {
    "JUPYTERHUB_SINGLEUSER_APP": "jupyter_server.serverapp.ServerApp",
}
c.JupyterHub.authenticator_class = "jupyterhub.auth.PAMAuthenticator"

class MyBatchSpawner(batchspawner.GridengineSpawner):
    req_sgeroot = Unicode(os.getenv("SGE_ROOT", "")).tag(config=True)
    req_hostname = Unicode(IP).tag(config=True)
    batch_script = Unicode(
        """#!/bin/sh
#$ -terse
#$ -N TEST
#$ -S /bin/sh
#$ -j y
#$ -notify
#$ -wd {homedir}
#$ -v {keepvars}

export NO_PROXY={hostname},$NO_PROXY
export no_proxy={hostname},$no_proxy

{cmd}
"""
    ).tag(config=True)
    batch_submit_cmd = Unicode("SGE_ROOT={sgeroot} {sgeroot}/bin/lx-amd64/qsub").tag(
        config=True
    )
    batch_query_cmd = Unicode(
        "SGE_ROOT={sgeroot} {sgeroot}/bin/lx-amd64/qstat -xml"
    ).tag(config=True)
    batch_cancel_cmd = Unicode(
        "SGE_ROOT={sgeroot} {sgeroot}/bin/lx-amd64/qdel {job_id}"
    ).tag(config=True)

    def parse_job_id(self, output):
        return output.split(".")[0]

c.JupyterHub.spawner_class = MyBatchSpawner
c.Spawner.ip = "0.0.0.0"
c.Spawner.debug = True
c.JupyterHub.log_level = "DEBUG"

jupyterhub / batchspawner

Voila doesn't render notebooks with JupyterHub and BatchSpawner #209

Bug description

Your personal set up