<?php

// anyway to start you request is fine.  In this script the $_GET request is not required.
// basically we build a JSON string from a number of simple Linux indicators:

if ($_GET['loadavg'] == '1') {
    $out = '{';
    $out .= getLoads();
    $out .= getLEDIndicator('mysqldump');
    $out .= getLEDIndicator('gzip');
    $out .= getLEDIndicator('find');
    $out .= getLEDIndicator('rsync');
    $out .= getdiskPercent('md2');
    $out .= getMem('MemFree');
    $out .= getMem('Cached');
    $out .= getprocessCPU('all');
    $out .= getprocessCPU('apache2');
    $out .= getprocessCPU('mysqld');
    $out .= getprocessCounts('apache2');
    $out .= getprocessCounts('rsync');
    $out .= '}';

    // on our server we have a  can_moderate() function that controls access to the JSON file
    // however, you can use any access control method you like:

    if (can_moderate()) {
        header('Access-Control-Allow-Origin: *');
        echo $out;
    }

}

// the functions are simple, and self explanatory and could be further combined
// but you get this idea:

function getprocessCounts($get = 'rsync')
{
    $target = 'ps aux | grep ' . $get . ' | grep -v grep | wc -l';
    $target_results = shell_exec($target);
    $output = ',"' . $get . 'count":"' . trim($target_results) . '"';

    return $output;
}

function getLoads()
{
    $string = file_get_contents('/proc/loadavg');
    $loadavg = explode(' ', $string);

    $n = 0;
    for ($n = 0; $n < count($loadavg); $n++) {
        $key = 'load' . $n;
        if ($n < count($loadavg) - 1) {
            $output .= '"' . $key . '":"' . trim($loadavg[$n]) . '",';
        } else {
            $output .= '"' . $key . '":"' . trim($loadavg[$n]) . '"';
        }

    }

    return $output;
}

function getLEDIndicator($get = 'apache2')
{
    $cmd = 'ps aux | grep ' . $get . ' | grep -v grep | wc -l';
    $cmd_results = shell_exec($cmd);
    $output = ',"' . $get . '":"' . trim($cmd_results) . '"';
    return $output;
}

function getdiskPercent($get = 'md2')
{
    $df = 'df | grep ' . $get . ' | grep -v grep';
    $df_results = shell_exec($df);
    $usage = preg_split('/\s+/', $df_results);
    $percent = explode('%', $usage[4]);
    $output = ',"' . $get . '":"' . trim($percent[0]) . '"';
    return $output;
}

function getMem($get = 'MemFree')
{
    $getMem = 'cat /proc/meminfo | grep ' . $get;
    $getMem_results = shell_exec($getMem);
    $mem = preg_split('/\s+/', $getMem_results);
    $output = ',"' . strtolower($get) . '":"' . trim($mem[1]) . '"';
    return $output;
}

function getprocessCPU($get = 'mysqld')
{
    $sum = 0;
    if ($get == 'all') {
        $doit = 'ps -eopcpu,comm';
    } else {
        $doit = 'ps -eopcpu,comm | grep ' . $get;
    }

    $results = shell_exec($doit);
    if ($get == 'all') {
        $clean = explode(' ', $results);
    } else {
        $clean = explode($get, $results);
    }

    foreach ($clean as $line) {

        if (s_has_letters(trim($line)) or trim($line) == '') {
            continue;}
        {
            if (strlen($line) > 0) {
                $sum += trim($line);
            }

        }
    }
    $output = ',"' . strtolower($get) . '":"' . trim($sum) . '"';
    return $output;
}

function s_has_letters($string)
{
    return preg_match('/[a-zA-Z]/', $string);
}

{
  "load0": "0.69",
  "load1": "0.57",
  "load2": "0.56",
  "load3": "1/291",
  "load4": "29704",
  "mysqldump": "0",
  "gzip": "0",
  "find": "0",
  "rsync": "0",
  "md2": "18",
  "memfree": "54970768",
  "cached": "5185620",
  "all": "39.5",
  "apache2": "35.8",
  "mysqld": "3.6",
  "apache2count": "93",
  "rsynccount": "0"
}