Can't add another ExtendedTask while the one is running? about shiny

[MohoWu]

Ok, I figured this out. I can't define a second ExtendedTask with the same name. I thought shiny module would handle the namespace automatically but apparently not. To fix the issue put ExtendedTask$new where it only run once (i.e. inside the server function), and pass the task as an argument to shiny module.

if (interactive()) {
  library(shiny)
  
  task_btn_ui <- function(id) {
    ns <- NS(id)
    tagList(
      
      bslib::input_task_button(
        id = ns("btn"),
        label = "task"
      ),
      shiny::textOutput(ns("msg"))
    
    )
  }
  
  task_btn_server <- function(id, task) {
    moduleServer(
      id,
      function(input, output, session) {
        ns <- session$ns
        
        task |> bslib::bind_task_button("btn")
        
        
        shiny::observeEvent(input$btn, {
          task$invoke()
        })
        
        output$msg <- shiny::renderText({
          task$result()
        })
        
      }
      
    )
  }
  

  ui <- bslib::page_fluid(
    shiny::actionButton("add_task", "Add Task"),
    shiny::div(
      id = "container"
    )
  )

  server <- function(input, output, session) {
    
    future::plan(future::multisession)
    
    task <- ExtendedTask$new(
      function() {
        promises::future_promise({
          Sys.sleep(10)
          "Success"
        })
      }
    ) 
    
    shiny::observeEvent(input$add_task, {
      
      rid <- stringi::stri_rand_strings(1, 10)
      
      shiny::insertUI(
        "#container",
        ui = task_btn_ui(rid)
      )
      
      task_btn_server(rid, task)
      
    })
  
  }

  shinyApp(ui, server)
}