# sampler.sh (run INSIDE the bench or the box): sample the cgroup of each named container from its birth, every 2 s.
# usage: NAMES="a b c" OUT=/root/mem.csv DUR=900 bash sampler.sh &     — stops at DUR or when $OUT.stop exists
: > $OUT; t0=$(date +%s)
while [ $(( $(date +%s) - t0 )) -lt ${DUR:-900} ] && [ ! -f $OUT.stop ]; do
  for n in $NAMES; do
    id=$(docker ps -q --no-trunc --filter name=^$n$ | head -1); [ -z "$id" ] && continue
    cg=$(ls -d /sys/fs/cgroup/system.slice/docker-$id.scope 2>/dev/null || find /sys/fs/cgroup -maxdepth 4 -type d -name "*$id*" 2>/dev/null | head -1)
    [ -f "$cg/memory.stat" ] || continue
    echo "$(date +%s),$n,${id:0:12},$(awk '$1=="anon"{print $2}' $cg/memory.stat),$(cat $cg/memory.current),$(cat $cg/memory.swap.current 2>/dev/null || echo NA),$(awk '$1=="oom_kill"{print $2}' $cg/memory.events),$(cat $cg/memory.max),$(docker inspect -f '{{.RestartCount}}' $id)" >> $OUT
  done
  sleep 2
done