Kill or stop execution of PHP script initiated by CRON?

Question

I have scheduled a CRON which calls/executes a PHP script every five minutes. PHP script perform following tasks

1. Checks for the flag value in database to identify if the previous run is still executing. Value of 1 in the DB tells that process is still running while a value of 0 means it is not.
2. If the flag value is 1, then exit the PHP else continue to next step.
3. Update the flag value in database from 0 to 1.
4. Execute the business logic.
5. Update the flag value back from 1 to 0, so that next CRON can executes if the data is available in user tables.

All works fine so far, depending on the size of user uploaded data the process on an average takes 35 to 40 minutes to complete.

Question, Is there anyway to kill or stop the execution of PHP script once started by cron. May be a button to let users stop the execution, upload new data and wait for CRON run. I can take care of reseting all the flags and data it's just the kill of PHP script is what i am trying to figure out.

I did some google and figured i can use some commands like:

Killall -9 PHP

to kill all php processes running on server, but not sure how to do this through PHP.

Answer 1

Try this:

ps aux |grep 'part_of_the_name_of_your_script'|awk '{print $2}' |xargs kill -9 {}

Or in your crontab file use crun and variable CRUN_TIME see crun -h

Answer 2

You can try system() or exec(), but it might not work (or return permission denied errors) as cron processes are executed by either the current user or root, and the web server user doesn't usually have access to these processes.