bramr / stack-heartbeat

example.php

<?php

For compatibility and reusability of your code, PSR1 recommends that a file should introduce either new symbols (like classes, functions, etc.) or have side-effects (like outputting something, or including other files), but not both at the same time. The first symbol is defined on line 32 and the first side effect is on line 2.

require_once './vendor/autoload.php';

use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;
use Stack\CallableHttpKernel;
use BramR\Stack\Heartbeat;

$diContainer = array('db.name' => 'super_important_production_db');

$app = new  CallableHttpKernel(function (Request $request) {

The parameter $request is not used and could be removed.

    return new Response('#yolo');
});

$app = (new Stack\Builder)
    ->push(Heartbeat::class)
    ->push(Heartbeat::class, '/just-a-diffent-route')
    ->push(Heartbeat::class, '/custom', function () use ($diContainer) {
        return new Response(
            'Custom heartbeat to check some stuff in db:' . $diContainer['db.name']
        );
    })
    ->push(Heartbeat::class, '/cpu', new CPULoadChecker)
    ->push(Heartbeat::class, '/cpu15m', new CPULoadChecker(CPULoadChecker::INTERVAL_15M))
    ->resolve($app);

Stack\run($app);

/**
 * As an example: super simple cpu load checker class.
 **/
class CPULoadChecker

PSR1 recommends that each class must be in a namespace of at least one level to avoid collisions.

{
    const INTERVAL_1M = 0;
    const INTERVAL_5M = 1;
    const INTERVAL_15M = 2;

    private $interval;

    public function __construct($interval = self::INTERVAL_1M)
    {
        $this->interval = $interval;
    }

    public function __invoke()
    {
        $load = sys_getloadavg();
        if (isset($load[$this->interval])) {
            return new Response($load[$this->interval], 200, array('Content-Type' => 'text/plain'));
        } else {
            return new Response('Whoops!', 500, array('Content-Type' => 'text/plain'));
        }
    }
}