Node.js HTTP service watchdog

http-service-watchdog.php

#!/usr/bin/env php
<?php

ini_set('display_errors', 'On');
error_reporting(E_ALL);
set_time_limit(0);





$serviceHost = '127.0.0.1';
$servicePort = 1234;
$command = 'some-service start --port ' . $servicePort;
$serviceBinDirectory = '/usr/local/bin';

$timeout = 8;
$debug = false;








if ($debug) {
    echo "Setting up environment... ";
}

putenv('PATH=' . getenv('PATH') . ':' . $serviceBinDirectory);

if ($debug) {
    echo "OK.\n";
}

$expectedResponse = '{"error":"Not found"}';

function inspectCode(int $code, int $expected = 0) {
    global $debug;

    if ($expected !== $code) {
        if ($debug) {
            echo "Got exit code $code. Terminated.\n";
        }

        exit($code);
    }
}

if ($debug) {
    echo "Checking service... ";
}

$uri = $serviceHost . ':' . $servicePort;

$ch = curl_init($uri);

curl_setopt_array($ch, [
    CURLOPT_HEADER => false,
    CURLOPT_SSL_VERIFYPEER => false,
    CURLOPT_TIMEOUT => $timeout,
    CURLOPT_RETURNTRANSFER => true,
]);

$response = curl_exec($ch);
curl_close($ch);

if ($expectedResponse === $response) {
    if ($debug) {
        echo "OK.\n";
    }

    exit(0);
}

if ($debug) {
    echo "bad response.\n";
    echo "Looking for a process... ";
}

exec('ps -ef | grep some-service ', $output, $code);

inspectCode($code);

if ($debug) {
    echo "OK.\n";
}

$pid = null;
$process = null;

foreach ($output as $line) {
    $pieces = preg_split('#\s+#', $line, 8);

    if (false === $pieces || !isset($pieces[7])) {
        if ($debug) {
            echo "Can\'t parse line \"$line\". Terminated.\n";
        }

        exit(1);
    }

    $process = $pieces[7];

    if (preg_match('#^node /(?:\pL+/)*some-service start#u', $process)) {
        $pid = $pieces[1];

        break;
    }
}

if (null === $pid) {
    if ($debug) {
        echo "Process is not found.\n";
    }
} else {
    echo "Process \"$process\" [PID $pid] found.\n";
    echo "Killing process... ";

    exec('kill -9 ' . $pid, $output, $code);

    inspectCode($code);

    if ($debug) {
        echo "OK.\n";
    }
}

if ($debug) {
    echo "Starting new process... ";
}

exec('nohup ' . $command . ' >> /dev/null 2>&1 &', $output, $code);

inspectCode($code);

if ($debug) {
    echo "OK.\n";
    echo "Done.\n";
}

exit(0);