Re-enable forked processing in RStudio Jobs and RStudio Terminal?

[HenrikBengtsson]

@graemeblair wrote in #299 (comment):

Hi -- late to this, but wondering if supportsMulticore() should return TRUE when run within RStudio 1.2 "jobs" feature (and still FALSE when run interactively). As I understand it, when code is run through jobs it is separated from the GUI interactions that complicate using plan(multicore) in RStudio run interactively. This would enable the same scripts that use plan(multicore) to be used in and out of RStudio with a bit less hassle.

I took the conservative approach and disabled forked processing anywhere in RStudio by testing for environment variable RSTUDIO.

It could be that it's only unsafe when running R via the RStudio Console (the "RStudio GUI"), but that it indeed works when running R via the RStudio Terminal (Tools -> Terminal -> New Terminal) or as an RStudio Job. I know one can distinguish RStudio Console from RStudio Terminal as:

is_rstudio_console <- function() {
  (Sys.getenv("RSTUDIO") == "1") && !nzchar(Sys.getenv("RSTUDIO_TERM"))
}

is_rstudio_terminal <- function() {
  (Sys.getenv("RSTUDIO") == "1") &&  nzchar(Sys.getenv("RSTUDIO_TERM"))
}

Source: https://github.com/HenrikBengtsson/startup/blob/0.12.0/R/is_rstudio.R

1. Could someone check how to detect whether R via an RStudio Job or not?

2. Then we also need to reach out to the RStudio GUI folks about forked processing in the above three cases of running R from RStudio.

[rdrr1990]

I just stumbled across this; since the terminal feature of RStudio is fairly new, I would recommend adding a version check to RStudio as well, perhaps along the lines of bigKRLS's:

https://github.com/rdrr1990/bigKRLS/blob/master/R/utils.R

[HenrikBengtsson]

Thxs, though, I'm not sure I understand. The gist of what we want to disable multicore processing when in RStudio Console, which we could detect using

(Sys.getenv("RSTUDIO") == "1") && !nzchar(Sys.getenv("RSTUDIO_TERM"))

Shouldn't that work also with older versions of RStudio that does not use RSTUDIO_TERM.

What I don't know is if RStudio Jobs run in yet another kind of environment and if there's a way to detect this.

[graemeblair]

Thanks for opening this @HenrikBengtsson.

The following set of flags work in R 3.6.0 on OS X with RStudio 1.2.1139:

is_rstudio_console <- function() {
  (Sys.getenv("RSTUDIO") == "1") && !nzchar(Sys.getenv("RSTUDIO_TERM")) && !nzchar(Sys.getenv("SHLVL"))
}

is_rstudio_terminal <- function() {
  (Sys.getenv("RSTUDIO") == "1") && nzchar(Sys.getenv("RSTUDIO_TERM"))
}

is_rstudio_job <- function() {
  (Sys.getenv("RSTUDIO") == "1") && !nzchar(Sys.getenv("RSTUDIO_TERM")) && nzchar(Sys.getenv("SHLVL")) 
}

Not sure about on other OS's or if this will generally work. I discovered these through inspecting Sys.getenv() in each of the three environments.

[HenrikBengtsson]

FYI, I've posted a follow-up question to RStudio about this to rstudio/rstudio#2597 (comment).

[grantmcdermott]

Graeme's code seems to work nicely on my system too. (Arch Linux with R 3.6.6 and RStudio 1.2.1335.)

[comicfans]

testing SHLVL gives incorrect result if start Rstudio from shell

interactive() can distinct if this is Rstudio job, since Rstudio said

Local jobs run as non-interactive child R processes of your main R process

I've tested that running interactive() as local job gives FALSE

[graemeblair]

Hi @HenrikBengtsson - the RStudio issue that was opened related to this seems to have been closed more than a year ago (rstudio/rstudio#2597) as resolved in PR rstudio/rstudio#6492. Are there broader issues about forking preventing multicore being allowed for use again with RStudio?

[HenrikBengtsson]

Hi. Are you asking specifically about running R via the RStudio Terminal or RStudio Jobs, as this issue referring to, or are you asking about doing in the RStudio Console (which most people mean when they say "in RStudio")?

For the RStudio Console, I don't think anything has changed, cf. rstudio/rstudio#2597 (comment). If something has changed, would you mind asking the RStudio folks to confirm.

If you want to be a daredevil, see ?parallelly::supportsMulticore for how to re-enable forked processing in RStudio.