Introduction to how PHP creates a single-instance background process method

This article mainly introduces the method of PHP to create a single background process, involving PHP for process start, create, judge, stop and other related operations skills, the need for friends can refer to the next

The example in this article describes how PHP creates a singleton background process. Share to everyone for your reference, as follows:

You can start a PHP background process by using the following statement:

$command = "php script.php"; $pid = EXEC ("nohup $command >/dev/null 2>&1 & Echo $!");

Nohup indicates that the process is independent of the created user and can be run as a daemon.

If you want this background process to run as a singleton, you can record/determine if the process is running by using the following method

Query the database for process id$query = "Select pid from ' daemons ' WHERE ' pid ' = ' LIMIT 1 '; $result = mysql_query ($query); $pid = mysql_result ($result, 0, ' pid '),//check if the process is runningexec ("PS $pid", $pState); if ((Count ($pSta TE) >= 2) &&!empty ($pid)) {echo "RUNNING";} Else{echo "INACTIVE";}

You can also write the PID to a file, but in a distributed task environment, it is better to put it in the database.

To stop a background process:

Check if the process from the database is Runningexec ("PS $pid", $pState), if ((count ($pState) >= 2)) {//if the process Is running, kill ITexec ("Kill $pid");//update database row and an empty process ID}