Schedule a Background Job — rs

Utilizes 'RStudio' job scheduler if correct environment is detected, otherwise call system command via Rscript

Usage

rs_exec(
  expr,
  name = "Untitled",
  quoted = FALSE,
  rs = TRUE,
  as_promise = FALSE,
  wait = FALSE,
  packages = NULL,
  focus_on_console = FALSE,
  ...,
  nested_ok = FALSE
)

Arguments

expr: R expression
name: used by 'RStudio' as name of the job
quoted: is expr quoted
rs: whether to use 'RStudio' by default
as_promise: whether to return as a promise object; default is no
wait: whether to wait for the result.
packages: packages to load in the sub-sessions
focus_on_console: whether to return back to console after creating jobs; useful when users want to focus on writing code; default is false. This feature works with 'RStudio' (>=1.4)
...: internally used
nested_ok: whether nested rs_exec is allowed; default is false; Set to true to allow nested parallel code, but use at your own risk.

Value

If wait=TRUE, returns evaluation results of expr, otherwise a function that can track the state of job.

Details

'RStudio' provides interfaces jobRunScript to schedule background jobs. However, this functionality only applies using 'RStudio' IDE. When launching R from other places such as terminals, the job scheduler usually result in errors. In this case, the alternative is to call system command via Rscript

The expression expr will run a clean environment. Therefore R objects created outside of the context will be inaccessible from within the child environment, and packages except for base packages will not be loaded.

There is a small difference when running within and without 'RStudio'. When running via Rscript, the environment will run under vanilla argument, which means no load, no start-up code. If you have start-up code stored at ~/.Rprofile, the start-up code will be ignored. When running within 'RStudio', the start-up code will be executed. As of rstudioapi version 0.11, there is no 'vanilla' option. This feature is subject to change in the future.

Examples


if(interactive()){
  h <- rs_exec(
    {
      Sys.sleep(2)
      print(Sys.getpid())
    },
    wait = FALSE, name = 'Test',
    focus_on_console = TRUE
  )
  code <- h()
  print(code)

  # wait 3 seconds
  Sys.sleep(3)
  code <- h()
  attributes(code)
}