I have an Ubuntu VM running in VirtualBox that hosts a server using Apache. The concept of the server is to accept HTTP POST requests, store them in a MySQL database and then execute a Python script with the relevant POST data to be displayed in a Discord channel.
The process itself is working but each time the PHP script calls the Python script, a new process is created that never actually ends. After a few hours of receiving live data the server runs out of available memory due to the amount of lingering processes. The PHP script has the following exec call as the last line of code;
exec("python3 main.py $DATA");
I would like to come up with a way to actually kill the processes created from this exec command (using user www-data), either in the Python file after the script is executed or automatically with an Apache setting that I probably just do not know about.
When running the following command in a terminal I can see the different processes;
ps -o pid,user,%mem,command ax | sort -b -k3 -r
There are 3 separate processes that show up, 1 referencing the actual python3 exec command as marked up in PHP;
9903 www-data 0.4 python3 main.py DATADATADATADATADATADATA
Then another process showing the more common -k start commands;
9907 www-data 0.1 /usr/sbin/apache2 -k start
And lastly another process very similar to the PHP exec command;
9902 www-data 0.0 sh -c python3 main.py DATADATADATADATADATADATA
How can I ensure Apache cleans these processes up - OR what do I need to add into my Python or PHP code to appropriately exec a Python script without leaving behind processes?
Didn't realize the exec command in php would wait for a return output indefinitely. Added this to the end of the string I was using in my exec call; > /dev/null &
i.e.: exec("python3 main.py $DATA > /dev/null &");
Related
I have a long running PHP script that runs on a Raspberry Pi which periodically checks the CPU temperature via the following command:
exec('/bin/cat /sys/class/thermal/thermal_zone0/temp')/1000
This works fine.
I also want to capture the CPU load by parsing the output of the top command run like so:
exec('/usr/bin/top -n 1 -p 0', $output, $code)
Oddly this only works if I run the PHP script interactively, it doesn't run when the script is executed under the PHP-CLI (started from the sudo crontab) yet the cat command runs under both. The value of $code returned is 1 which seems to indicate that the process couldn't run or wouldn't run.
Why the difference and how would I get the output of top so that I can parse it ?
So I'm using a Putty session to run a script on background.
my script can be located by
cd /var/www/listingapp.
Then I will run the command
php /var/www/listingapp/public/index.php batch/GetPrefecture init > /dev/null &
so I'm expecting that the script will run in background, but after I close the putty CLI and try to re-open it, the process can no longer be found when entering the command
ps aux | grep /var/www/listingapp
So this means it stopped. How do I make it to run in background when session is terminated?
nohup php /var/www/listingapp/public/index.php batch/GetPrefecture init &
I have MATLAB r2013b, IIS 7.5, php 5.6 on Windows Server 2008 and trying to do the following:
<?php
...
chdir($matlabScriptsDir);
exec("matlab -r test_func(args) -logfile $logfile", $output);
$output shows that process exited with code 0, in the TaskManager I see MATLAB.exe running from the user IUSR, $logfile is created and locked by this process, but the process does nothing – just hangs (there are no issues with running the same command from cmd.exe).
Where is the problem?
using the -r option is like entering commands to Matlab's command line, so after the command is executed you still have Matlab running, waiting for your next command. Try instead:
matlab -r "test_func(args), exit"
So that the Matlab process will end. I suggest you do even more, and wrap it with a try-catch (followed by exit) so that in case of an error the process will not hang.
I try to plan one-time job with 'at' command. There is next code in script:
$cmd = 'echo "/usr/bin/php '.$script_dir.$script_name.' '.$args.'"|/usr/bin/at "'.$time.'" 2>&1';
exec($cmd, $output , $exit_code);
When I run this command from script it adds the job to the schelude. This I see by the line in logs job 103 at Thu Sep 3 15:08:00 2015 (same text contains $output). But then nothing happens in specified time like at ignores the job. And there are no error messages in logs.
When I run same command with same args from command line on server it scheludes the job and than runs it at specified time.
I found out that when I try to plan a job via php script it runs under apache user. I tried to run next in command line on server:
sudo -u apache echo "/usr/bin/php /var/www/pant/data/www/pant.com/scripts/Run.php firstarg secondarg "|/usr/bin/at "16:00 03.09.2015"
It works correct too. I checked sudoers and have added apache user with NOPASSWD privileges. Script Run.php has execute rights.
at.deny is empty. at.allow does not exist.
So question is: why 'at' does not run command given via php script (exec) but runs same command in command line? How to run it?
Thanks to all.
I found by chance answer at stackexchange.com:
The "problem" is typically PHP is intended to run as module in a webserver. You may need to install the commandline version of php before you can run php scripts from the commandline
I am using this code on Ubuntu 13.04,
$cmd = "sleep 20 &> /dev/null &";
exec($cmd, $output);
Although it actually sits there for 20 seconds and waits :/ usually it works fine when using & to send a process to the background, but on this machine php just won't do it :/
What could be causing this??
Try
<?PHP
$cmd = '/bin/sleep';
$args = array('20');
$pid=pcntl_fork();
if($pid==0)
{
posix_setsid();
pcntl_exec($cmd,$args,$_ENV);
// child becomes the standalone detached process
}
echo "DONE\n";
I tested it for it works.
Here you first fork the php process and then exceute your task.
Or if the pcntl module is not availabil use:
<?PHP
$cmd = "sleep 20 &> /dev/null &";
exec('/bin/bash -c "' . addslashes($cmd) . '"');
The REASON this doesn't work is that exec() executes the string you're passing into it. Since & is interpreted by the shell as "execute in the background", but you don't execute a shell in your exec call, the & is just passed along with 20 to the /bin/sleep executable - which probably just ignores that.
The same applies to the redirection of output, since that is also parsed by the shell, not in exec.
So, you either need to find a way to fork your process (as described above), or a way to run the subprocess as a shell.
My workaround to do this on ubuntu 13.04 with Apache2 and any version of PHP:
libssh2-php, I just used nohup $cmd & inside a local SSH session using PHP and it ran it just fine the background, of course this requires putting certain security protocols in place, such as enabling SSH access for the webserver user, so it would have exec-like permissions then only allowing localhost to login to the webserver ssh account.