Issue with Shiny App Deployment: Works Locally but Fails on Server

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1

Hello everyone,

I'm encountering a frustrating issue with deploying my Shiny app. The app runs perfectly on my local machine, but when I deploy it to the server, it fails with the following error in the logs:

Warning: Error in pickerInput: could not find function "pickerInput"

I'm facing an issue with my Shiny app that works perfectly fine locally but encounters errors after deploying to the server. I've made sure to include all the necessary packages in my app.R file, and I've tried reinstalling them on the server. Despite this, I'm getting errors related to missing functions and packages.

Here are the main issues I'm encountering:

  1. Function Not Found Errors: Despite having shinyWidgets and bslib loaded and working locally, the server throws errors saying functions like pickerInput and bs_theme are not found.
  2. Package Installation: I ensured all required packages are installed in the app.R script using install_if_missing, but the server logs still indicate issues with missing packages or functions. This happens even though the same setup works without issues on my local machine.
  3. Environment Differences: I suspect there might be some differences between the local and server environments that are causing these issues, but I'm not sure where to look or how to resolve this.

I've tried tagging the key packages like bslib, but couldn't find shinyWidgets in the tags. Any advice on how to troubleshoot this or if anyone has faced similar issues would be greatly appreciated!

2

Does your app load every library it uses with an explicit library() command?

3

In my local environment, yes, but I don't know about the server's. So to avoid this problem, I had to make sure to add this code in my app.R :

required_packages <- c("shiny", "ggplot2", "reshape2", "gridExtra", "tidyverse", 
                       "shinyWidgets", "multcomp", "agricolae", "dplyr", "bslib")

install_if_missing <- function(pkg) {
  if (!requireNamespace(pkg, quietly = TRUE)) install.packages(pkg)
}

lapply(required_packages, install_if_missing)

library(shiny)
library(ggplot2)
library(reshape2)
library(gridExtra)
library(tidyverse)
library(shinyWidgets)
library(multcomp)
library(agricolae)
library(dplyr)
library(bslib)

I had this issue for the first time with bs_theme() function not found by creating my_theme variabletheme = my_theme so instead I added it directly to the ui :

fluidPage(theme = bs_theme(
    version = 4,
    bg = "#1a1a2e",  # Very dark background
    fg = "#e4e4f0",  # Light text
    primary = "#6A5ACD",  # Slate Blue
    secondary = "#2C2C54",  # Dark Gray for accents
    base_font = "Helvetica, Arial, sans-serif",  # Fallback to system fonts
    heading_font = "Verdana, Geneva, sans-serif"  # Fallback to system fonts
  ),

It resulted an error for mistaking function's name with another's in other package. So I made sure it's from bslib package :

bslib::bs_theme()

Then the error was updated :slight_smile: . Now it couldn't find font_google() function from the same package. So to avoid complexity I used the default font.

And I thought it worked for bslib but then pickerInput is not found :upside_down_face: .

4

I can't recall where I saw it, but I'm pretty sure I read something reliable that said you should not attempt to install packages on shinyapps.io. So I would suggest removing the code prior to the first library statement.

The calls to library() look fine, and loading shinyWidgets should get you the pickerInput() function. You might try creating a minimal example, containing the pickerInput widget and not much else, and see if that can be deployed. If yes, we need to search for some other culprit. If no, hopefully a deployment error message will tell us something.