Method analysis on the implementation principle of script daemon in PHP

This article mainly introduces the principle and implementation method of the PHP script daemon process. It analyzes the implementation ideas, principles, formats and specific implementation methods of the PHP script daemon process in more detail. Friends in need can refer to it

The examples in this article describe the principles and implementation methods of the php script daemon. Share it with everyone for your reference, the details are as follows:

Ideas:

1. While loop, if there is currently no data to operate, you can sleep;
2. The crontab script executes the script every fixed period of time. When executing, first check whether it is already being executed. If it is not executed, skip it.
3. nohup background execution
4. flock -xn lock

Example:

Code to be executed: index. php

<?php
set_time_limit(0);
//死循环
while(1) {
  $message = &#39;1111111&#39; . "\n";
  error_log($message);
  sleep(5);
}

#/tmp/lock/test1.lock 为当前进程要锁定的文件，不同的进程配置不同的锁文件，该文件会自动创建
* * * * * flock -xn /tmp/lock/test1.lock -c 'nohup php index.php >> /php/test.log 2>&1 &'
* * * * * flock -xn /tmp/mytest.lock -c 'php /home/fdipzone/php/test.php >> /home/fdipzone/php/test.log'

is writing the php script. To prevent daemon process memory overflow, it is recommended to regularly check memory usage.
Put the following code into the business script:

if(memory_get_usage()>100*1024*1024){
  exit('内存溢出');//大于100M内存退出程序，防止内存泄漏被系统杀死导致任务终端
}

Note:

nohup task View and close methods:

Close:

//方法一：
ps -e | grep commend
kill -9 pid
//方法二：
fg %n  //n为jobs命令查看的进程号

View:

//查看后台进程
jobs

Principle:

Use linux flock file lock to implement task locking and resolve conflicts

Format:

flock [-sxun][-w #] fd#
flock [-sxon][-w #] file [-c] command

Options

-s, --shared: Get a shared lock
-x, --exclusive: Get a Exclusive lock
-u, --unlock: Remove a lock, which is usually unnecessary. The lock will be automatically discarded after the script is executed
-n, --nonblock: If the lock is not obtained immediately, it will fail directly instead. Wait
-w, --timeout: If the lock is not obtained immediately, wait for the specified time
-o, --close: Close the file descriptor before running the command. Used to control the locking process if the command spawns a child process
-c, --command: Run a separate command in the shell
-h, --help Display help
-V, - -version: Display version

Run a php file. The file lock uses an exclusive lock. If it is locked, it will fail without waiting. The parameters are -xn

* * * * * flock -xn /tmp/mytest.lock -c 'php /home/fdipzone/php/test.php >> /home/fdipzone/ php/test.log'

In this way, when the task is not completed and the next task determines that /tmp/mytest.lock is locked, the current task will be ended and the judgment will be made again in the next cycle.

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