Simple helpers to run tasks before/until the deadline.

helper.php

if (! function_exists('stop_before')) {
    function stop_before(callable $func, DateTimeInterface $dt)
    {
        $tz = $dt->getTimezone();
        $now = new DateTime('now', $tz);

        if ($now > $dt) {
            call_user_func($func);
        }

        return;
    }
}

if (! function_exists('run_until')) {
    function run_until(callable $func, DateTimeInterface $dt)
    {
        $tz = $dt->getTimezone();
        $now = new DateTime('now', $tz);

        if ($now <= $dt) {
            call_user_func($func);
        }

        return;
    }
}

// Example
$deadline = DateTime::createFromFormat(/* ... */);

run_until(function () {
    // do something
}, $deadline);