Hi,
I’ve been progressing well with setting up cylc hub service on our server PUMA2. We are deploying behind a reverse web proxy. I have checked our cylc hub installation by running a browser direct on PUMA2 and all seems to be fine, but through the reverse proxy I’m seeing a couple of issues.
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When I log in to jupyterhub I’m greeted with the “Spawning UI server” message but it never redirects to my UI server. If I manually change the url to https://....../user/ros it correctly connects to my UI server and displays all my workflows. Not sure if I’m missing something in the jupyter_config file or the reverse proxy? If I log out of jupyterhub and back in again it then correctly connects to my already running UI server and loads my workflows.
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Has anyone had problems with the rendering of UI web pages with Cylc Hub running via a reverse web proxy?
The colouring is all up the swanny and pop up windows are transparent making it very difficult to use - see image below.
Any ideas gratefully received. Thanks.
Version info:
ros@puma2$ cylc version --long
8.4.0 (/home4/home/n02-puma/fcm/metomi/cylc-8.4.0-2/bin/cylc)
Plugins:
cylc-rose 1.5.0 /home/n02/n02/fcm/metomi/cylc-8.4.0-2/lib/python3.9/site-packages
cylc-uiserver 1.6.1 /home/n02/n02/fcm/metomi/cylc-8.4.0-2/lib/python3.9/site-packages
Hi 
,
Very curious, unfortunately, we haven’t encountered either of these two issues ourselves. The rendering of the page is especially peculiar, e.g. the Cylc logo in the top left should appear in colour, I think these colours are hardcoded into the logo itself so I really don’t understand how it can appear in black and white. Very confusing.
Things to check:
- When you’re on the “Spawning UI server” page, there’s an option to view the event log, check if this contains anything interesting.
- The Jupyter Hub log may also contain pertinent information.
- When you’ve accessed your server and have the Cylc UI open in a browser tab, open the “web inspector” (usually F12, or accessed via an application menu). Open the “network” tab and refresh the page to reveal information about the requests being sent by the browser. Let us know if any of those requests failed, maybe we’re missing CSS files or something?
- Jupyter Hub launches its own reverse proxy, if you are running Jupyter Hub via an additional proxy, check the configuration isn’t messing with anything. Jupyter Hub has some notes on this. It wouldn’t explain what you are seeing, but worth checking that the proxy doesn’t kill idle websocket connections (this is a common issue).
- For the spawning issues, check the Jupyter Hub troubleshooting page.
Thanks Oliver.
Thanks for the reminder about the “web inspector”, I could see from that, that some content was being blocked by the reverse proxy content security policy header setting. Once that was resolved the pages all rendered correctly and the “Spawning UI server” page auto updated and then redirected to the user dashboard correctly.
I don’t want to speak too soon, but I think we’re nearly all setup now. 
Cheers
Ros.
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