Error: startup took too long

[malanbos]

Hi,
I am getting the following error when trying to re-publish my Shiny app:

Any advice please?

[malanbos]

The app.R file that I use for the Shiny app, sources another R script (using source()), which runs a linear model with multiple predictors, with interaction (e.g. lm(x1~x2x3x4*x5, data). This typically takes more that a minute to execute. Could this be the issue?

[Rodrigue]

Hi @malanbos

What the logs of your app say? Can you provide a reproducible example (reprex) illustrating your issue?

Shiny debugging and reprex guide

Shiny issues can be challenging to resolve relative to other problems with your code or statistical methods. Shiny apps are often large, complex projects with interacting files. When seeking help from others it is considered polite to: First, do your best to work through RStudio's debugging tools to diagnose your issue on your own. Often those shiny logs and tracebacks are useful to others trying to help out. Second, strive to minimize the effort required to replicate your issue. You can do this with a reproducible example ("reprex"). Shiny Debugging Errors in Shiny code can be difficult to track down. If you don't know where your problem is coming from, you can track it down with some o…

[josh]

Sounds likely. Is it possible to pre-compute the model before deploying the application? Or compute it asynchronously, for example using promises?

[malanbos]

Thanks for pointing me in that direction. I will explore the options and try to apply it to my app.

[malanbos]

This worked! Pre-computing the model solved the issue. I use one script to pre-compute the model, and write the output to a file. (This only needs to be updated weekly)

The Shiny app then assigns the written file to a variable to be used, instead of having to run the model as part of the Shiny deployment.

I haven't yet checked out asynchronous computing...