I am working on a custom module for Magento 2. I did setup crontab there and it is working good with static schedule.

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../app/code/Magento/Cron/etc/crontab.xsd">
    <group id="default">
        <job name="tm-feed-job" instance="TM\Feed\Model\Cron" method="export">
            <schedule>* * * * * *</schedule>

But I need the <schedule>* * * * * *</schedule> dynamic from my database saved value. Here I need to use 3 schedule Daily Weekly Monthly

Frequency already saved in database enter image description here

How can i add dynamic schedule there?

2 Answers 2


Not as easy as I expected.

First you need to update your crontab.xml to setup the config path to your frequency:

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../app/code/Magento/Cron/etc/crontab.xsd">
    <group id="default">
        <job name="tm-feed-job" instance="TM\Feed\Model\Cron" method="export">

Now you need to add a field to the configuration to be able to choose the frequency so in adminhtml/system.xml :

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Config:etc/system_file.xsd">
        <section id="vendor">
            <group id="module" translate="label" type="text" sortOrder="1" showInDefault="1" showInWebsite="0" showInStore="0">
                <label>Cron Settings</label>
                <field id="frequency" translate="label" type="select" sortOrder="1" showInDefault="1" showInWebsite="0" showInStore="0">
                <field id="time" translate="label" type="time" sortOrder="2" showInDefault="1" showInWebsite="0" showInStore="0">
                    <label>Start Time</label>

Now we need to create Vendor\Module\Model\Config\Backend\Frequency for the frequency backend model:


namespace Vendor\Module\Model\Config\Backend;

class Frequency extends \Magento\Framework\App\Config\Value
     * Cron string path
    const CRON_STRING_PATH = 'crontab/default/jobs/tm_feed_job/schedule/cron_expr';

     * Cron model path
    const CRON_MODEL_PATH = 'crontab/default/jobs/tm_feed_job/run/model';

     * @var \Magento\Framework\App\Config\ValueFactory
    protected $_configValueFactory;

     * @var string
    protected $_runModelPath = '';

     * @param \Magento\Framework\Model\Context $context
     * @param \Magento\Framework\Registry $registry
     * @param \Magento\Framework\App\Config\ScopeConfigInterface $config
     * @param \Magento\Framework\App\Cache\TypeListInterface $cacheTypeList
     * @param \Magento\Framework\App\Config\ValueFactory $configValueFactory
     * @param \Magento\Framework\Model\ResourceModel\AbstractResource $resource
     * @param \Magento\Framework\Data\Collection\AbstractDb $resourceCollection
     * @param string $runModelPath
     * @param array $data
    public function __construct(
        \Magento\Framework\Model\Context $context,
        \Magento\Framework\Registry $registry,
        \Magento\Framework\App\Config\ScopeConfigInterface $config,
        \Magento\Framework\App\Cache\TypeListInterface $cacheTypeList,
        \Magento\Framework\App\Config\ValueFactory $configValueFactory,
        \Magento\Framework\Model\ResourceModel\AbstractResource $resource = null,
        \Magento\Framework\Data\Collection\AbstractDb $resourceCollection = null,
        $runModelPath = '',
        array $data = []
    ) {
        $this->_runModelPath = $runModelPath;
        $this->_configValueFactory = $configValueFactory;
        parent::__construct($context, $registry, $config, $cacheTypeList, $resource, $resourceCollection, $data);

     * {@inheritdoc}
     * @return $this
     * @throws \Exception
    public function afterSave()
        $time = $this->getData('groups/module/fields/time/value');
        $frequency = $this->getData('groups/module/fields/frequency/value');

        $cronExprArray = [
            intval($time[1]), //Minute
            intval($time[0]), //Hour
            $frequency == \Magento\Cron\Model\Config\Source\Frequency::CRON_MONTHLY ? '1' : '*', //Day of the Month
            '*', //Month of the Year
            $frequency == \Magento\Cron\Model\Config\Source\Frequency::CRON_WEEKLY ? '1' : '*', //Day of the Week

        $cronExprString = join(' ', $cronExprArray);

        try {
        } catch (\Exception $e) {
            throw new \Exception(__('We can\'t save the cron expression.'));

        return parent::afterSave();

This code looks tricky at first sight but it basically generates the crontab/default/jobs/tm_feed_job/schedule/cron_expr config path based on what you've chosen in the frequency dropdown.

Interesting side note finding: this is implemented for a couple of modules in M2 natively which includes currency, product alerts, backups, sitemaps. The interesting thing is where the backend model are defined for some of those modules:

  • Product Alert: Magento\Cron\Model\Config\Backend\Product\Alert
  • Sitemap: Magento\Cron\Model\Config\Backend\Sitemap

So yeah you read it right. Instead of being in their corresponding module folder, those backend models are located under the Magento\Cron module folder.

  • thank you for the note - but wanted to ask what is runModel doing here. Pelase explain
    – Abid Malik
    Commented Oct 11, 2019 at 12:08
  • You always come up with a good solution. +1 :) Commented Oct 28, 2019 at 6:11
  • What the use of runModelPath ? Is it required to add this?
    – DJ Dev
    Commented Dec 27, 2019 at 11:36
  • its not working in magento 2.3.3. cron not run as per time set in configuration. my cron run at 00:01 everyday but i have set time 10:30 and Frequency "Daily".
    – nil108
    Commented Jan 22, 2020 at 12:04

When looking at \Magento\Cron\Observer\ProcessCronQueueObserver::_generateJobs it would suffice to create an varchar input at the specified config key for your respective <config_path> value to be read from core_config_data.

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