I have developed a shiny app, first have to run SQL queries which need around 5-10 minutes to be ran. The building of the plots afterwards is quite fast.
My idea was to run the queries once per day (with invalidLater) before shinyServer(). This worked well.
Now I got access to a shiny server. I could save my app in ~/ShinyApps/APPNAME/ and access it by http://SERVERNAME.com:3838/USER/APPNAME/. But if I open the app, while it is not open in some other browser it takes 5-10 min to start. If I open it, while it is also open on another computer it starts fast.
I have no experience with severs, but I conclude my server only runs the app as long someone is accessing it. But in my case it should be run permanently, so it always starts fast and can update the data (using the sql queries) once per day.
I looked up in the documentation, since I guess it is some setting problem.
To keep the app running:
Brute force: You can have a server/computer, have a view of your app open all the time so it does not drop from shiny server memory. but that won't load new data.
Server settings: you can set the idle time of your server to a large interval, meaning it will wait that interval before dropping your app from memory. This is done in the shiny-server.conf file with fx. app_idle_timeout 3600
To have daily updates:
Crontab: Set up a crontab job in your SSH client fx. PuTTY: $ crontab -e
like this(read more: https://en.wikipedia.org/wiki/Cron):
00 00 * * * Rscript /Location/YourDailyScript.R
YourDailyScript.R:
1. setwd(location) #remember that!
2. [Your awesome 5 minute query]
3. Save result as .csv or whatever.
and then have to app just load that result.