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Is this R process inside a Slurm job?

Source: R/slurm_inside_job.R
inside_slurm_job.Rd

Reports whether Slurm started this R process. A script that submits itself calls this, so it submits from the login session and never from inside the job.

Usage

inside_slurm_job()

Value

TRUE when this process runs inside a Slurm job, and FALSE otherwise.

Details

Without the test, the submitting branch runs inside the job as well, and the job submits itself again:

if (!inside_slurm_job()) {
  slurm_submit(slurm_write(jobs, dir))
  quit(save = "no")
}
# Below here runs inside the job.

What it reads

It reads SLURM_JOB_ID first. It falls back to SLURM_JOBID, which the sbatch manual page keeps for backward compatibility. Measured on Slurm 25.11.2: a login shell carries no SLURM_ variable at all, and a one-task job carries 33 of them.

Any non-empty value counts as inside a job. A digit check would be wrong, because a heterogeneous job carries an id such as 17+1. A false negative there makes the payload submit itself, which costs more than a false positive from a hand-set variable.

plnr::is_run_directly() does not answer this question. It tests the call depth, not the environment. Measured on this machine, it returns TRUE on the login node and inside a Slurm job.

See also

vignette("batchit"), section "Slurm: write a chain of jobs".

Other slurm: slurm_it(), slurm_status(), slurm_submit(), slurm_write()

Examples

inside_slurm_job()
#> [1] FALSE