negotiation.bash

#!/usr/bin/env bash

# set -x
set -m

# bash strict mode
set -euo pipefail

max_workers=$(( $(nproc) * 2 ))

lock_name='negotiation'
lock_dir='/tmp'
lock_timeout=60

lock_prefix="${lock_dir}/${lock_name}_"

for id in $(seq 1 "$max_workers"); do
  touch "${lock_prefix}${id}"
done

function main() {
  lock_id=1

  # 20 simulated tasks
  for i in $(seq 1 20); do

    rand=$(( RANDOM % 10 ))
    task="sleep ${rand} && echo '"

    lock_file="${lock_prefix}${lock_id}"

    echo "task: ${i} ('${task}') ${lock_file}"

    flock -w "$lock_timeout" -x "$lock_file" -c "${task} sleep of ${rand} w/ lock: ${lock_file}'" &

    lock_id=$(( lock_id + 1 ))

    if [ "$lock_id" -ge "$max_workers" ]; then
      lock_id=1
    fi

  done

  wait

  rm -fv ${lock_prefix}*
}

main