Artificially slow Shiny app for testing/debugging purposes

global.R

library(shiny)

# Configure delays using the following constants.

# before worker starts responding to listeners
STARTUP_DELAY_SECS = 0

# time to load ui.R (before first "/" response only)
UI_INIT_DELAY_SECS = 0

# before any "/" response (including first)
UI_DELAY_SECS = 0

# time spent on the client after "/" response but before requesting websocket
CLIENT_DELAY_SECS = 2

# time to load server.R (before first websocket conn only)
SERVER_INIT_DELAY_SECS = 0

# time for websocket conn to be processed (every time, including first)
SERVER_DELAY_SECS = 0

# End config constants



start_time <- Sys.time()
options(digits.secs = 3)

Sys.sleep(STARTUP_DELAY_SECS)

server.R

Sys.sleep(SERVER_INIT_DELAY_SECS)

function(input, output, session) {
  Sys.sleep(SERVER_DELAY_SECS)

  output$time <- renderText(format(Sys.time()))
  output$pid <- renderText(Sys.getpid())
}

shiny-server.conf

# Instruct Shiny Server to run applications as the user "shiny"
run_as shiny;

# reconnect false;

# Define a server that listens on port 3838
server {
  listen 3838;

  # Define a location at the base URL
  location / {

    # Host the directory of Shiny Apps stored in this directory
    site_dir /shiny-server/superslow;

    # Log all Shiny output to files in this directory
    log_dir /var/log/shiny-server;

    # When a user visits the base URL rather than a particular application,
    # an index of the applications available in this directory will be shown.
    directory_index on;

    utilization_scheduler 1 0.2 20;
  }
}

admin 4151 {
  required_user "**";
}

ui.R

Sys.sleep(UI_INIT_DELAY_SECS)

function(req) {
  Sys.sleep(UI_DELAY_SECS)

  fluidPage(
    tags$script(HTML(sprintf("
    function sleep(seconds)
    {
      var e = new Date().getTime() + (seconds * 1000);
      while (new Date().getTime() <= e) {}
    }
    sleep(%f);
  ", CLIENT_DELAY_SECS))),
    withTags(
      table(
        tr(
          td("Process started at:"),
          td(format(start_time))
        ),
        tr(
          td("UI generated at:"),
          td(format(Sys.time() - start_time))
        ),
        tr(
          td("Server executed at:"),
          td(textOutput("time", inline = TRUE))
        ),
        tr(
          td("UI process PID:"),
          td(Sys.getpid())
        ),
        tr(
          td("Server process PID:"),
          td(textOutput("pid", inline = TRUE))
        )
      )
    )
  )
}