I have an application hosted on the free tier of ShinyApps.io which calls callr::r_bg() to initiate some long-running processes in the background. This works without a problem on my local machine, but the deployment on ShinyApps.io seems to be blocking the initialization of these new processes. Does anyone know if this is intended behavior?
(post deleted by author)
Additional details:
I run background processes which are saved to a reactive value, and I later try to access the results of the background processes with get_result(). I receive the following error message on ShinyApps.io.
Warning: Error in get_result(out, private$options): ! callr subprocess failed: could not start R, exited with non-zero status, has crashed or was killed
However, I have no issues running the app on my MacBook where I'm developing or on Linux (Ubuntu 22.02) where I simply downloaded the application and ran. The function for starting the background process is below
run_simulations_in_background <- function(sample_size, sample_prob, prob0, prob1, niter, included = "all",
.rng_kind = NULL, .rng_normal_kind = NULL, .rng_sample_kind = NULL,
tempfile = NULL) {
callr::r_bg(function(sample_size, sample_prob, prob0, prob1, niter, included,
.rng_kind, .rng_normal_kind, .rng_sample_kind, tempfile) {
run_simulation_wrapper <- function(sample_size, sample_prob, prob0, prob1, niter, included,
.rng_kind, .rng_normal_kind, .rng_sample_kind, tempfile) {
lapply(sample_size, function(x) {
try(writeLines(as.character(x), con = tempfile))
ordinalsimr::run_simulations(x, sample_prob = sample_prob, prob0 = prob0, prob1 = prob1, niter = niter, included = included,
.rng_kind = .rng_kind, .rng_normal_kind = .rng_normal_kind, .rng_sample_kind = .rng_sample_kind
)
}) |>
unlist(recursive = FALSE)
}
run_simulation_wrapper(sample_size, sample_prob, prob0, prob1, niter, included,
.rng_kind, .rng_normal_kind, .rng_sample_kind, tempfile)
},
args = list(sample_size, sample_prob, prob0, prob1, niter, included,
.rng_kind, .rng_normal_kind, .rng_sample_kind, tempfile),
package = "ordinalsimr"
)
}