Describe the problem in detail
I'm building an interactive dashboard that performs some time-consuming computations, and I am trying to add progress bars to show the user that the app is making progress. Ironically, in the process, I've created some kind of lock condition where the app gets stuck. The point where it gets stuck seems to be variable; on my last run, it stalled on iteration 485063.
I've reduced the app to a minimal reprex, below, and deployed it here: https://ezra-morrison.shinyapps.io/stuck-progress/
I'd be grateful for any debugging suggestions!
Thanks,
Ezra
Example application
library(shiny)
library(glue)
library(dplyr)
#>
#> Attaching package: 'dplyr'
#> The following objects are masked from 'package:stats':
#>
#> filter, lag
#> The following objects are masked from 'package:base':
#>
#> intersect, setdiff, setequal, union
ui <- fluidPage(
numericInput("n iterations", inputId = "n.iter", value = 10^6, min = 0, step = 1),
actionButton("Start", inputId = "goButton", class = "btn-success"),
plotOutput("plot")
)
loop_function = function(session, nmax = 10^5)
{
message("here")
progress <- Progress$new(session, min=1, max=nmax)
on.exit(progress$close())
progress$set(message = 'Calculation in progress',
detail = 'This may take a while...')
step_function = function(i)
{
progress$inc(amount = 1, detail = glue::glue("On iteration {i} out of {nmax}"))
NA
}
dataset =
tibble(id = 1:nmax) |>
group_by(id) |>
summarize(
.groups = "drop",
temp = step_function(id[1])
# in my motivating application, real computation steps would occur here
)
plot(cars)
}
server <- function(input, output, session)
{
plot1 =
loop_function(session = session, nmax = input$n.iter) |>
eventReactive(eventExpr = input$goButton)
output$plot = plot1() |> renderPlot()
}
shinyApp(ui, server)
#>
#> Listening on http://127.0.0.1:7587
Created on 2022-09-02 with reprex v2.0.2
Deployed app is here: https://ezra-morrison.shinyapps.io/stuck-progress/
System details
Output of devtools::session_info():
─ Session info ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────
setting value
version R version 4.2.1 (2022-06-23 ucrt)
os Windows 10 x64 (build 22000)
system x86_64, mingw32
ui RStudio
language (EN)
collate English_United States.utf8
ctype English_United States.utf8
tz America/New_York
date 2022-09-02
rstudio 2022.07.1+554 Spotted Wakerobin (desktop)
pandoc 2.18 @ C:/Program Files/RStudio/bin/quarto/bin/tools/ (via rmarkdown)
─ Packages ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
package * version date (UTC) lib source
askpass 1.1 2019-01-13 [1] CRAN (R 4.2.1)
assertthat 0.2.1 2019-03-21 [1] CRAN (R 4.2.1)
cachem 1.0.6 2021-08-19 [1] CRAN (R 4.2.1)
callr 3.7.2 2022-08-22 [1] CRAN (R 4.2.1)
cli 3.3.0 2022-04-25 [1] CRAN (R 4.2.1)
clipr 0.8.0 2022-02-22 [1] CRAN (R 4.2.1)
conflicted * 1.1.0 2021-11-26 [1] CRAN (R 4.2.1)
crayon 1.5.1 2022-03-26 [1] CRAN (R 4.2.1)
credentials 1.3.2 2021-11-29 [1] CRAN (R 4.2.1)
curl 4.3.2 2021-06-23 [1] CRAN (R 4.2.1)
DBI 1.1.3 2022-06-18 [1] CRAN (R 4.2.1)
devtools * 2.4.4 2022-07-20 [1] CRAN (R 4.2.1)
digest 0.6.29 2021-12-01 [1] CRAN (R 4.2.1)
dplyr * 1.0.9 2022-04-28 [1] CRAN (R 4.2.1)
ellipsis 0.3.2 2021-04-29 [1] CRAN (R 4.2.1)
evaluate 0.16 2022-08-09 [1] CRAN (R 4.2.1)
fansi 1.0.3 2022-03-24 [1] CRAN (R 4.2.1)
fastmap 1.1.0 2021-01-25 [1] CRAN (R 4.2.1)
fs 1.5.2 2021-12-08 [1] CRAN (R 4.2.1)
generics 0.1.3 2022-07-05 [1] CRAN (R 4.2.1)
glue 1.6.2 2022-02-24 [1] CRAN (R 4.2.1)
highr 0.9 2021-04-16 [1] CRAN (R 4.2.1)
htmltools 0.5.3 2022-07-18 [1] CRAN (R 4.2.1)
htmlwidgets 1.5.4 2021-09-08 [1] CRAN (R 4.2.1)
httpuv 1.6.5 2022-01-05 [1] CRAN (R 4.2.1)
jsonlite 1.8.0 2022-02-22 [1] CRAN (R 4.2.1)
knitr 1.40 2022-08-24 [1] CRAN (R 4.2.1)
later 1.3.0 2021-08-18 [1] CRAN (R 4.2.1)
lifecycle 1.0.1 2021-09-24 [1] CRAN (R 4.2.1)
magrittr 2.0.3 2022-03-30 [1] CRAN (R 4.2.1)
memoise 2.0.1 2021-11-26 [1] CRAN (R 4.2.1)
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openssl 2.0.2 2022-05-24 [1] CRAN (R 4.2.1)
pillar 1.8.1 2022-08-19 [1] CRAN (R 4.2.1)
pkgbuild 1.3.1 2021-12-20 [1] CRAN (R 4.2.1)
pkgconfig 2.0.3 2019-09-22 [1] CRAN (R 4.2.1)
pkgload 1.3.0 2022-06-27 [1] CRAN (R 4.2.1)
prettyunits 1.1.1 2020-01-24 [1] CRAN (R 4.2.1)
processx 3.7.0 2022-07-07 [1] CRAN (R 4.2.1)
profvis 0.3.7 2020-11-02 [1] CRAN (R 4.2.1)
promises 1.2.0.1 2021-02-11 [1] CRAN (R 4.2.1)
ps 1.7.1 2022-06-18 [1] CRAN (R 4.2.1)
purrr 0.3.4 2020-04-17 [1] CRAN (R 4.2.1)
R.cache 0.16.0 2022-07-21 [1] CRAN (R 4.2.1)
R.methodsS3 1.8.2 2022-06-13 [1] CRAN (R 4.2.0)
R.oo 1.25.0 2022-06-12 [1] CRAN (R 4.2.0)
R.utils 2.12.0 2022-06-28 [1] CRAN (R 4.2.1)
R6 2.5.1 2021-08-19 [1] CRAN (R 4.2.1)
Rcpp 1.0.9 2022-07-08 [1] CRAN (R 4.2.1)
remotes 2.4.2 2021-11-30 [1] CRAN (R 4.2.1)
reprex * 2.0.2 2022-08-17 [1] CRAN (R 4.2.1)
rlang 1.0.4 2022-07-12 [1] CRAN (R 4.2.1)
rmarkdown 2.15 2022-08-16 [1] CRAN (R 4.2.1)
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sessioninfo 1.2.2 2021-12-06 [1] CRAN (R 4.2.1)
shiny 1.7.2 2022-07-19 [1] CRAN (R 4.2.1)
stringi 1.7.8 2022-07-11 [1] CRAN (R 4.2.1)
stringr 1.4.1 2022-08-20 [1] CRAN (R 4.2.1)
styler 1.7.0 2022-03-13 [1] CRAN (R 4.2.1)
sys 3.4 2020-07-23 [1] CRAN (R 4.2.1)
tibble 3.1.8 2022-07-22 [1] CRAN (R 4.2.1)
tidyselect 1.1.2 2022-02-21 [1] CRAN (R 4.2.1)
urlchecker 1.0.1 2021-11-30 [1] CRAN (R 4.2.1)
usethis * 2.1.6 2022-05-25 [1] CRAN (R 4.2.1)
utf8 1.2.2 2021-07-24 [1] CRAN (R 4.2.1)
vctrs 0.4.1 2022-04-13 [1] CRAN (R 4.2.1)
withr 2.5.0 2022-03-03 [1] CRAN (R 4.2.1)
xfun 0.32 2022-08-10 [1] CRAN (R 4.2.1)
xtable 1.8-4 2019-04-21 [1] CRAN (R 4.2.1)
yaml 2.3.5 2022-02-21 [1] CRAN (R 4.2.1)
[1] C:/Users/Work/AppData/Local/R/win-library/4.2
[2] C:/Program Files/R/R-4.2.1/library
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