CODEWITHSUNDEEP
phpcron
Oleg
Oleg

Reputation: 2821

function to check if php is already executed for cron

Ealier I used function in a seperate file that could be call by script for cron.

function processExists($file = false) {

   $exists     = false;
   $file       = $file ? $file : basename(__FILE__);

   $command = "ps -ef | grep -v grep | grep $file";
   exec($command, $pids);
   if (count($pids) > 1) {
      $exists = true;
   }
   return $exists;
}

It could be executed from any php script as:

if (processExists(basename(__FILE__))) {
   echo 'Process in already running ';
   exit(0);
}

For some reason it doesn't work in Debian6. Now I add in the beginning of every script:

$fh = fopen(__FILE__, 'r');
if (!flock($fh, LOCK_EX | LOCK_NB)) {
   echo 'Script is already running!!!' . "\n";
   exit(0);
}

It causes duplication of code in every script I tried to create function in a seperate file to call from any php script when neccessary, for example something like this:

function stopIfRunning($file)
{
    $fh = fopen($file, 'r');
    if(!flock($fh, LOCK_EX | LOCK_NB)) {
        echo 'Script is already running!!!' . "\n";
        exit(0);
    }
}

And calling from php script:

stopIfRunning(__FILE__);

But it doesn't work in this case. Could you please explain why it doesn't work in this case?

Upvotes: 1

Views: 689

Answers (3)

Oleg
Oleg

Reputation: 2821

It seems the problem is with $fh on stopIfRunning function. If the file with with functiona changed it with: 

$fh = null;
function stopIfRunning($file)
{
    global $fh;
    echo $file, "\n";
    $fh = fopen($file, 'r');
    if (!$fh) {
        echo 'Failed to open file', "\n";
    }
    if(!flock($fh, LOCK_EX | LOCK_NB)) {
        echo 'Script is already running!!!' . "\n";
        exit(0);
    }
}

And call it in the file that should be launched using cron:

stopIfRunning(__FILE__);

Here global variable is used, which is not good. It would be great if somebody suggest a solution without global variable.

Upvotes: 0

Ramil Amerzyanov
Ramil Amerzyanov

Reputation: 1291

FILE it is name of running file.

stopIfRunning(__FILE__);

function stopIfRunning($file)
{
    $fh = fopen($file, 'r');
    ....
}

Here you tried open this executed file for lock.

Upvotes: 0

Roman Newaza
Roman Newaza

Reputation: 11690

If you need to make sure the service is running, use Daemontools or Monit.

And personally, I would use plain Bash, not PHP, if custom implementation needed.

BTW, you can easily debug your ps command in terminal.

Upvotes: 1

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