Does DISABLE_WP_CRON prevent plugins from registering new cron tasks?

Question

If I set DISABLE_WP_CRON to true in my wp-config.php file, then will it block plugins from registering new cron events (eg with calls to wp_schedule_event())

define( 'DISABLE_WP_CRON', true );

I've added the above line to my wp-config.php. I think the general assumption is that DISABLE_WP_CRON doesn't actually block your cron jobs from running (and block plugins from registering new events), but that it just prevents wordpress itself from initiating your crons when a visitor loads your website in their web browser.

And, instead, you can just set DISABLE_WP_CRON to true and then execute your cron jobs outside of the web server (eg with wp-cli and the actual, system cron).

Is this assumption valid? Or does DISABLE_WP_CRON actually block crons from running, and block plugins from registering new cron events?

I ask because I'm writing a plugin that tries to register a new cron event with wp_schedule_event(). The function returns True, but the new cron job does not appear in my event list, so I don't think it will ever be executed by my system's cron.

wp cron event list

How can I prevent wordpress from executing its own cron via the webserver when my visitors load the website through their web browsers, but still permit [a] crons to be executed by tools like wp-cli and [b] plugins to register new cron events?

Answer 1

Is this assumption valid? Or does DISABLE_WP_CRON actually block crons from running, and block plugins from registering new cron events?

Yes, setting DISABLE_WP_CRON to true doesn't actually block Wordpress' crons from running; it just prevents wordpress itself from initiating the events to run when your backend is triggered by a customer viewing your website.

I'm writing a plugin that tries to register a new cron event with wp_schedule_event(). The function returns True, but the new cron job does not appear in my event list, so I don't think it will ever be executed by my system's cron.

wp cron event list will not list all of your crons if you're using wordpress multisite.

I don't know of a built-in way to get wp-cli to just dump all of the crons for all of your sites, but here's a simple bash loop that will iterate through each of your sites and list all scheduled cron events for each site.

urls=$(wp site list --field=url)
for url in $urls; do
    echo ${url}
    sudo cron --url=${url} event list
    echo
done