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Shiny server debugging

Open sebsilas opened this issue 4 years ago • 1 comments

Hi Peter,

It can be quite difficult to debug apps on Shiny Server when using the psychTestR framework (although perhaps this is a general Shiny problem). Whilst I usually test everything locally first before uploading, sometimes new errors only present themselves on the server.

The issue is that if something crashes when running a psychTestR experiment on Shiny Server, you don't get an informative error. In the browser console, you usually get:

Screenshot 2021-12-07 at 08 06 44

Or Shiny might say, "ERROR: An error has occurred. Check your logs or contact the app author for clarification."

However, when you get those kind of errors, app logs are not produced (ie., /var/log/shiny-server/blah.log).

Ideally, somewhere you want to see what you'd normally see in your R console when testing locally.

Perhaps I am missing a trick or a new feature would be required.

Can you recommend a way to do this, or if it requires a new feature, point me in the right direction to work on it?

All the best, Seb

sebsilas avatar Dec 07 '21 08:12 sebsilas

Hi @syntheso I think it's worth spending some more time looking at the standard Shiny procedures here. I have to look these up each time unfortunately! But there's quite a lot of information on Google. I know there are several log files, for example. There's also an option in the server config to give 'real' error messages on the frontend, which is really handy for debugging.

pmcharrison avatar Dec 07 '21 19:12 pmcharrison