Generate a crontab time table showing all the times tasks run at

cron-timetable-generate.php

<?php

require_once './vendor/autoload.php';

/** @todo read straight from the crontab file */
$jobs = [
    'task1' => [
        '0 6 * * *'           => (new \Cron\CronExpression('0 6 * * *')),
        '45 7 * * *'          => (new \Cron\CronExpression('45 7 * * *')),
        '15 8 * * *'          => (new \Cron\CronExpression('15 8 * * *')),
        '30 8 * * *'          => (new \Cron\CronExpression('30 8 * * *')),
        '45 8 * * *'          => (new \Cron\CronExpression('45 8 * * *')),
        '00 8,12,15,18 * * *' => (new \Cron\CronExpression('00 8,12,15,18 * * *')),
        '30 12 * * *'         => (new \Cron\CronExpression('30 12 * * *')),
        
    ],
    'task2' => [
        '*/20 9,10,11,13,14,16,17,19,20 * * *' => (new \Cron\CronExpression('*/20 9,10,11,13,14,16,17,19,20 * * *')),
        '20,40 12,15,18 * * *'                 => (new \Cron\CronExpression('20,40 12,15,18 * * *')),
    ],
    'task3' => [
        '18 8-18/4 * * *' => (new \Cron\CronExpression('18 8-18/4 * * *')),
    ],
    'task4' => [
        '35 19 * * *' => (new \Cron\CronExpression('35 19 * * *')),
    ],
    'task5' => [
        '10,30,50 9,10,11,13,14,15,17,18,19 * * *' => (new \Cron\CronExpression('10,30,50 9,10,11,13,14,15,17,18,19 * * *')),
        '10,30 16,20 * * *'                        => (new \Cron\CronExpression('10,30 16,20 * * *')),
        '10,35 12 * * *'                           => (new \Cron\CronExpression('10,35 12 * * *')),
    ],
    'task6' => [
        '50 8,12,16,20 * * *' => (new \Cron\CronExpression('50 8,12,16,20 * * *')),
    ]
];

$times = [];

/** Create a period of minutes for a full day */
$begin = (new DateTime())->setTimezone(new DateTimeZone('Europe/London'))->setTime(0, 0, 0);
$end = (new DateTime())->setTimezone(new DateTimeZone('Europe/London'))->setTime(23, 59, 59);
$interval = DateInterval::createFromDateString('1 minute');
$periods = new DatePeriod($begin, $interval, $end);

foreach ($jobs as $jobName => $jobTimes) {

    \array_walk($jobTimes, function($jobTime, $jobIndex) use ($periods, $jobName, &$times) {
        
        $previousNextJobTime = false;
        
        foreach ($periods as $period) {
            
            $period = $period->setTimezone(new DateTimeZone('Europe/London'));
            
            /* @var $period DateTime */
            /* @var $jobTime \Cron\CronExpression */
            
            $currentNextJobTime = (new \DateTime("@" . $jobTime->getNext($period)))->setTimezone(new DateTimeZone('Europe/London'));

            /** Skip periods between current period selection and the last next job calculated to run */
            if($previousNextJobTime && $period < $previousNextJobTime) {
                continue;
            }
            
            /** Skip previous next job time and current next job time if they are the same calulation */
            if($previousNextJobTime && $previousNextJobTime == $currentNextJobTime) {
                continue;
            }
            
            $endOfDayCutoff = (new DateTime())->setTime(23, 59, 59)->setTimezone(new DateTimeZone('Europe/London'));

            /** ignore if we've gone over the cutoff time */
            if($currentNextJobTime > $endOfDayCutoff) {
                continue;
            }
            
            $times[$jobName][$jobIndex] = $currentNextJobTime->format('Y-m-d H:i:s');
            
            echo $jobName . '|' . $jobIndex . '|' . $currentNextJobTime->format('Y-m-d H:i:s') . PHP_EOL;
            $previousNextJobTime = $currentNextJobTime;
            
        }
        reset($periods);
    });
}

z-composer.json

{
    "name": "vendor/crontab-analyser",
    "description": "Description of project crontab-analyser.",
    "authors": [
        {
            "name": "Kevin Andrews",
            "email": "[email protected]"
        }
    ],
    "require": {
        "poliander/cron": "^2.0"
    }
}