process_pool

#!/bin/bash

process_pool(){
    #
    if [ $# -lt 3 ]; then
        echo "$0 process_num command [args]"
        return 1
    fi
    _process_num=$1
    shift
    _func=$1
    shift
    if [[ ! $_process_num =~ ^[0-9]+$ ]]; then
        echo "process_num must be a number"
        return 1
    fi
    if !type $_func >/dev/null 2>&1; then
        echo "comannd must be executable"
        return 1
    fi

    # create fifo file
    fifo="/tmp/$$.fifo"
    mkfifo $fifo
    exec {FD}<>$fifo
    rm $fifo
  

    # create slot
    for i in $(seq $_process_num); do
        echo >&$FD
    done
  

    # run
    for arg in $@; do
        read -u $FD
        {
            $_func $arg 
            echo >&$FD
        }&
    done
 
    # wait
    wait

    # release slot fd
    exec {FD}>&-
}


test(){
    echo $1
    sleep 30
    return 0
}

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