How to run given function in Bash in parallel?

Question

There have been some similar questions, but my problem is not \"run several programs in parallel\" - which can be trivially done with parallel or xargs

Answer 1

Edit: Please consider Ole's answer instead.

Instead of a separate script, you can put your code in a separate bash function. You can then export it, and run it via xargs:

#!/bin/bash
dowork() { 
    sleep $((RANDOM % 10 + 1))
    echo "Processing i=$1, j=$2"
}
export -f dowork

for i in "${list[@]}"
do
    for j in "${other[@]}"
    do
        printf "%s\0%s\0" "$i" "$j"
    done
done | xargs -0 -n 2 -P 4 bash -c 'dowork "$@"' --