[HTCondor-users] Using classads in DOCKER_EXTRA_ARGUMENTS

[Joachim Meyer <jmeyer@xxxxxxxxxxxxxxxxxx>]

Hi all,
I wanted to make the --shm-size= argument of docker configurable on a per-job 
basis and thus tried setting the following options:

DOCKER_SHM_SIZE = ifThenElse(DevShmSize isnt Undefined && 
isInteger(DevShmSize), DevShmSize, 2147483648)
DOCKER_EXTRA_ARGUMENTS = --shm-size=$INT(DOCKER_SHM_SIZE)

Thus adding `+DevShmSize = 8589934592` in a job submission script would lead 
to `--shm-size=8589934592` being added to the docker command.

So far this always adds `--shm-size=2147483648`, though, wich as I understand 
it correctly stems from the fact that DOCKER_EXTRA_ARGUMENTS is not parsed 
with classAds enabled and the $INT(..) is evaluated without the job classads 
being set.

Is there an alternative way to forward these kinds of job specific custom 
arguments to the docker create command? (I guess one doesn't want to allow 
arbitrary contents here...)

Looking forward to any suggestions,
- Joachim