顺序和连续执行PHP脚本

Question

I have developed a script which should execute continuously and sequentially. Now on creating a cron job for this script, it keeps executing asynchronously.

1) I kept a while loop in script and thought of executing this script once so i used @reboot to execute the script once but if apache craches then this script will not start executing by its own ??

2)Using * * * * * cron it executes this script but creates multi-thread and all cron overlaps on the server eventually.

I have ran out of ideas how to execute a server script continuously and sequentially even if apache server restarts.

Answer 1

You're asking for:

a script which should execute continuously and sequentially

That's the definition of a daemon. You can use upstart to easily create a daemon with your php code.

Here you can find a good article to explain how create a daemon with upstart and node.js (but is easy to adapt to a php script): http://kvz.io/blog/2009/12/15/run-nodejs-as-a-service-on-ubuntu-karmic/

Answer 2

cron is for repeating jobs on a timed basis (min interval: 1 minute). It's intended for scripts that eventually exit and need to be restarted from scratch. Sounds like your script is essentially trying to be a daemon - started once, then left running permanently.

Instead of cron to repeatedly start new copies of the script, simply start your script ONCE via an init script, eg /etc/rc.local

Answer 3

有一些想法可以处理检查脚本是否在此问题中运行，并且您可以每隔几分钟运行一次cron以确保其运行，如果没有则启动它。