检查进程是否仍在运行? [英] Checking if process still running?

问题描述

作为构建穷人看门狗并确保应用程序崩溃的一种方法(直到我弄清原因)，我需要编写一个PHP CLI脚本，该脚本将由cron每5百万次运行一次以进行检查该进程是否仍在运行.

As a way to build a poor-man's watchdog and make sure an application is restarted in case it crashes (until I figure out why), I need to write a PHP CLI script that will be run by cron every 5mn to check whether the process is still running.

基于此页面，我尝试了以下代码，但始终即使我使用虚假数据调用也返回True:

Based on this page, I tried the following code, but it always returns True even if I call it with bogus data:

function processExists($file = false) {
    $exists= false;
    $file= $file ? $file : __FILE__;

    // Check if file is in process list
    exec("ps -C $file -o pid=", $pids);
    if (count($pids) > 1) {
    $exists = true;
    }
    return $exists;
}

#if(processExists("lighttpd"))
if(processExists("dummy"))
    print("Exists\n")
else
    print("Doesn't exist\n");

接下来，我尝试了此代码 ...

Next, I tried this code...

(exec("ps -A | grep -i 'lighttpd -D' | grep -v grep", $output);)
print $output;

...但是没有得到我所期望的:

... but don't get what I expect:

/tmp> ./mycron.phpcli 
Arrayroot:/tmp> 

FWIW，此脚本与PHP 5.2.5的CLI版本一起运行，并且操作系统为uClinux 2.6.19.3.

FWIW, this script is run with the CLI version of PHP 5.2.5, and the OS is uClinux 2.6.19.3.

谢谢您的提示.

这似乎工作正常

exec("ps aux | grep -i 'lighttpd -D' | grep -v grep", $pids);
if(empty($pids)) {
        print "Lighttpd not running!\n";
} else {
        print "Lighttpd OK\n";
}

推荐答案

我将使用pgrep进行此操作(警告，未经测试的代码):

I'd use pgrep to do this (caution, untested code):

exec("pgrep lighttpd", $pids);
if(empty($pids)) {

    // lighttpd is not running!
}

我有一个执行类似操作的bash脚本(但使用SSH隧道):

I have a bash script that does something similar (but with SSH tunnels):

#!/bin/sh

MYSQL_TUNNEL="ssh -f -N -L 33060:127.0.0.1:3306 tunnel@db"
RSYNC_TUNNEL="ssh -f -N -L 8730:127.0.0.1:873 tunnel@db"

# MYSQL
if [ -z `pgrep -f -x "$MYSQL_TUNNEL"` ] 
then
    echo Creating tunnel for MySQL.
    $MYSQL_TUNNEL
fi

# RSYNC
if [ -z `pgrep -f -x "$RSYNC_TUNNEL"` ]
then
    echo Creating tunnel for rsync.
    $RSYNC_TUNNEL
fi

您可以使用要监视的命令来更改此脚本.

You could alter this script with the commands that you want to monitor.

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