Time limit on long cron job?

Question

I'm working on a membership system which is going to process renewal payments.

If I use set_time_limit(0) inside the wp_schedule_event (cron) function, is that enough to ensure that it has the time it needs to execute the payment processing? We're using Stripe, and I assume their API responses will be around 1-2 seconds per transaction (hopefully less), but if I need to process a lot of transactions I'm worried about hitting the generic 30 second timeout.

I would prefer to set this at runtime and not globally in php.ini

Code example:

//CRON - Setup rebilling
add_action('dd_cron_rebill_expiry', 'dd_rebill_expiry');
add_action('init', function() {
               
   //Make sure we don't schedule duplicate events if this already exists!
   if (!wp_next_scheduled('dd_cron_rebill_expiry')) {
                            
   //Schedule hourly 
   $time = strtotime("+1 hours", strtotime(current_time('Y-m-d h:00:00'))); 
   wp_schedule_event($time, 'hourly', 'dd_cron_rebill_expiry');   
                    
}
                
});
            
#Rebill the user if their expiry date has been reached
function dd_rebill_expiry() {
 
  set_time_limit(0);  //will this work???

  //WP_User_Query goes here with 100 user maximum
  //Loop through all valid users & perform payment processing here
            
}

Answer 1

Further research has resulted in mixed information and no clear solution.

Our solution is to use a separate file and execute the script using CRON via the command-line, rather than relying on the Wordpress cron system. This has the added bonus of max_execution_time=0 as well. PHP Max execution time

Stripe's API seems to take about 2-3 seconds to process a transaction. If we limit our WP_User_Query to 100 users, that should take roughly 300-500 seconds to process an entire batch.

Since we are planning to execute our script hourly, I used set_time_limit=3500 (slightly under an hour), that way if something goes wrong it will be terminated before CRON executes the script again.