TL;DR:
I ran ./launcher rebuild app and then my forum broke. The problem ended up being a theme component that had been working. I don’t really understand the issue beyond that, but I’m posting in case my experience may be helpful to others.
Setup
I’m hosting discourse on a Digital Ocean Discourse Droplet (Ubuntu). I do not know what version my forum was on, but it was a fairly update beta (within the last week). It is now at 2.9.0.beta4.
Problem
After updating my containers/app.yml file, I ran ./launcher rebuild app. After the script completed, my forum came up with a 502 server error. Then it came up ‘empty’ as shown in this screenshot:
I undid my app.yml change and rebuilt with no luck. Clicking buttons didn’t seem to do anything, but maybe duplicate another ‘box’ (there are two in that screenshot, after clicking ‘+ New Topic’ there were three).
When I visited in a private browser window, my forum seemed to work: it requires a log-in. So it seemed something was working.
I finally stumbled upon how to view your forum in safe mode. It appeared to work when disabling everything.
Solution
Safe mode without disabling themes did not work but worked with all plugins. This lead me to disable the Topics Thumbnail theme component and then everything started working again. I am using the Graceful theme.
If I reenable this theme component, my site breaks as described above.
Updated Solution
There was a bug with Topics Thumbnail and it is now fixed.
Last Thoughts
I do not understand the 502 error I got. Perhaps my server is slow or the container running Discourse was not fully up by the time the launcher script was finished. Unless my forum was out of date and launcher automatically pulls updates, I’m not sure why my theme component started causing issues.
