Shell command works on command line but not in PHP exec

Question

I have a command that when run direct on the command line works as expected. It runs for over 30 seconds and does not throw any errors. When the same command is called through a PHP script through the php function exec() (which is contained in a script called by a cron) it throws the following error:

Maximum execution time of 30 seconds exceeded

We have a number of servers and i have run this command on a very similar server with the exact same dataset without any issues so i'm happy there is no script-level issue. I'm becoming more inclined to think this is related to something at the server level - either in the PHP setup or the server setup in some way but really not sure where to look. For those that are interested both servers have a max execution time of 30 seconds.

the command itself is called like this -

from command line as:

root@server>php -q /path/to/file.php

this works...

and via cron within a PHP file as:

exec("php -q /path/to/file.php");

this throws the max execution time error. it was always my understanding that there was no execution time limit when PHP is run from the command line.

I should point out that the script that is called, calls a number of other scripts and it is one of these scripts that is erroring. Looking at my logs, the max execution time error actually occurs before 30 seconds has even elapsed too! So, less than 30 seconds after being called, a script, called by a cron script that appears to be running as CLI is throwing a max execution error.

To check that the script is running as i expected (as CLI with no max execution time) i performed the following check:

A PHP script containing this code:

// test.php
echo exec("php test2.php");

where test2.php contains:

echo ini_get('max_execution_time');

and this script is run like this:

root@server> php test.php
// returns 0

This proves a script called in this way is running under CLI with a max execution time of 0 which just proves my thoughts, i really cannot see why this script is failing on max execution time!

Answer 1

it seems that your script takes too much time to execute, try to

set time limit, http://php.net/manual/en/function.set-time-limit.php

or check this post: Asynchronous shell exec in PHP

Answer 2

Does the command take over 30 seconds on the command line? Have you tried increased the execution timeout in the php.ini?

Answer 3

You can temporarily set the timeout by including this at the top of the script. This will not work when running in safe mode as is specified in the documents for setting max_execution_time with ini_set() .

<?php
    ini_set('max_execution_time', 60);  // Set to be longer than 
                                        // 60 seconds if needed

    // Rest of script...
?>

One thing of note in the docs is this:

When running PHP from the command line the default setting is 0.

Answer 4

What does php -v | grep cli php -v | grep cli , run from both the shell and in the exec command from the cron-loaded php file show?

Does explictly typing /usr/bin/php (modify as appropriate) make any difference?

Answer 5

I've actually found what the issue is (kinda). It seems that its maybe a bug with PHP reporting max_execution_time to be exceeded when the error is actually with max_input_time as described here

I tried changing the exec call to php -d max_execution_time=0 -q /path/to/file.php and i got the error "Maximum execution time of 0 seconds exceeded" which makes no sense, i changed the code to be php -d max_input_time=0 -q /path/to/file.php and the code ran without erroring. Unfortunately, its still running 10 minutes later. At least this proves that the issue is with max_input_time though

Answer 6

I'm surprised that no one above has actually timed the completed exec call. The problem is that exec(x) is taking a much longer time than command line x. I have a very complex perl script (with 8 levels of internal recursion) that takes about 40 sec to execute from the command line. Using exec inside a php script to call the same perl program takes about 300 sec to execute, ie, a factor of about 7X longer time. This is such an unexpected effect that people aren't increasing their max execution time sufficiently to see their programs complete. As a result, they are mystified by the timeout. (BTW, I am running on WAMP in a fast machine with nominally 8 cpus, and the rest of my php program is essentially trivial, so the time difference must be completely in the exec.)

Answer 7

create wrapper.sh file as below

export DISPLAY=:0<br>
xhost + 2>>/var/www/err.log<br>
/usr/bin/php "/var/www/read_sms1.php" 2>>/var/www/err.log<br>

and put it in cron as below

 bash  /var/www/wrapper.sh<br>
y read_sms1.php  contain<br>
$ping_ex = exec("/usr/local/bin/gnokii --getsms SM 1 end  ", $exec_result, $pr);  

and above solution workedfine for me in ubuntu 12.04