pshed

#!/bin/bash

function scheduler() {
    local -i fd=$1 worker_id= worker_fd=
#    local -a workers=$2
    local task=

    echo "Scheduler started"

    while read task
    do

        echo "Scheduler readed task \"$task\""

        read -u $fd worker_id

        echo "Scheduler readed free worker id \"$worker_id\""

        echo $workers
        echo ${workers[1]}
        worker_fd=${workers[$worker_id]}

        echo "Schedule found free worker[$worker_id,$worker_fd]"

        eval "echo \"$task\" >&$worker_fd"

        echo "Scheduler send task to worker[$worker_id,$worker_fd]"
    done
}

function worker() {
    local -i id=$1 fd=$2 queue_fd=$3
    local task=

    echo "Worker[$id,$fd] started"

    eval "echo $id >&$queue_fd"

    while read -u $fd task
    do
        if [[ -z $task ]]
        then
            echo "Worker[$id,$fd] ended"
            break
        fi

        echo "Worker[$id,$fd] task \"$task\" readed"

        eval $task

        echo "Worker[$id,$fd] task \"$task\" executed"

        eval "echo $id >&$queue_fd"

        echo "Worker[$id,$fd] free"
    done
}

function main() {
    local -i queue_fd=$1 workers_num=$2
    local -a workers=()
    local -i i= worker_fd=
    local pipes_dir= queue_pipe= worker_pipe=

    pipes_dir=$(mktemp -d /tmp/pshed.XXXXX)
    queue_pipe="$pipes_dir/$queue_fd"

    mkfifo $queue_pipe
    eval "exec $queue_fd<> $queue_pipe"

    for ((i=0; i<$workers_num; i++))
    do
        worker_fd=$(($queue_fd + $i + 1))
        worker_pipe="$pipes_dir/$worker_fd"

        mkfifo $worker_pipe
        workers[$i]=$worker_fd
        echo "Initialized worker ${workers[$i]}"

        eval "exec $worker_fd<> $worker_pipe"
        worker $i $worker_fd $queue_fd &
    done

    echo "Started scheduler with workers $workers"

#    scheduler $queue_fd $workers <&0
    scheduler $queue_fd <&0

    eval "exec $queue_fd>&-"

    for worker_fd in ${workers[@]}
    do
        eval "exec $worker_fd>&-"
        echo > "$pipes_dir/$worker_fd"
    done
}

main 4 $1