multiconcurrent users cause app crash

[Benoît Lancelin]

Hello,
I have some trouble sharing applications with a shiny server open source version.
If only one user launch the app, it works well. If a second user launch the app (on the same computer with another browser or on another computer), the first user app crashes giving the following error : "The application exited unexpectedly. read ECONNRESET"
(it seems that all the connections to the app use the same port)

This problem occurs on very simple apps :

ui.R
shinyUI(fluidPage(
  mainPanel(
    tags$hr(),
    helpText('Test'),
    tags$hr()
  )
))

server.R
shinyServer(function(input, output, session) {
  session$onSessionEnded(function() {
    stopApp()
  })
})

I was told that it was because I share parts of the app out of the app folder but this example doesn't use any extra files.
Thanks in advance for any piece of advice.

[Joe Cheng]

You're calling stopApp(), which stops the entire Shiny app for all users--that's what it's designed to do. You should never call stopApp in a Shiny Server scenario (at least, I can't think of when it could possibly be useful)--it's intended to be used for Shiny apps that are used directly from an R console, by an R user who can make use of the return value from runApp.

Shiny Server automatically stops Shiny apps a few seconds after the last user leaves, and will automatically start it the next time someone tries to connect. So your shinyServer function for this example should have a totally empty function body.

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