I want to have a simple PHP script that loops to do something every ten minutes. It would be hosted offsite, and I would activate it via my browser. I don't have access to the server other than my web space, so 'cron' as such isn't an option.
(I'm happy to have this stop after a certain time or number of job cycles. I just need it to continue running after I point the browser away from the page script.)
Is such a thing possible? Thanks.
It's possible, see ignore_user_abort():
set_time_limit(0);
ignore_user_abort(true);
while (true) // forever
{
// your code
}
You can use this two functions with a combination of sleep(), usleep(), time_nanosleep() or even better - time_sleep_until() to achieve a CRON-like effect.
PHP scripts timeout after a certain amount of time - they're not designed for long-running programs. You'll have to find some way to prod it every ten minutes.
Have a look at set_time_limit.
This is from the above page:
You can do set_time_limit(0); so that the script will run forever - however this is not recommended and your web server might catch you out with an imposed HTTP timeout (usually around 5 minutes).
Maybe you can write another script on a computer which you have access and then make that script request the other one periodically.
Yop can look at pnctl_fork.
Here's a hack for your problem:
// Anything before disconnecting, but nothing to be output to the client!
ob_end_clean();
header('Connection: close');
ob_start();
// Here you can output anything before disconnecting
echo "Bla bla bla";
$outsize = ob_get_length();
header('Content-Length: '.$outsize);
ob_end_flush();
flush();
// Do your background processing here
// and feel free to quit anytime you want.
A way to do this might be to launch a new php process from the web page, e.g.
<?php
exec("php script_that_runs_for_a_while.php > /dev/null");
?>
Adding the /dev/null means (on a linux system) that your script will complete, rather than waiting for the execution to finish.
So then that script that launches can do whatever it likes, since it is basically just a new process running on the server.
Note that at the start of your long running script, you will want to use the set_time_limit function to set the max execution time to some large value.
Related
Is it possible for nginx to trigger a php-fpm process, but then close the nginx worker and quickly return an empty page with status 200?
I have some slow php processes that need kicking off a few times a week. They can take between 3 and 4 minutes each. I trigger them with a cron manager site. The php process writes a lock file at the start, and when the process is complete an email is sent and finally the lock file is removed.
Following this guide, in my php-fpm worker pool, I have this: request_terminate_timeout = 300 and in my nginx site config I have fastcgi_read_timeout 300;
It works, but I don't care about the on-screen result. And the cron service I use has a time limit of 5 seconds, and after repeated timeouts, it disables the job.
Yes, I know I could fork a process in php, let it run in the background, and return a 200 to nginx. And yes, I could pay and upgrade my cron service. Nonetheless, it would be an interesting and useful thing to know, anyway.
So, is this possible, or does php-fpm require an open and "live" socket? I ask that because on the "increase your timeout" page referred to above, one answer says
"Lowest of three. It’s line chain. Nginx->PHP-FPM->PHP. Whoever dies
first will break the chain".
In other words, does that mean that I can never "trigger" a process, but then close the nginx part of the trigger?
You can.
exec a php cli script by adding a trailing &, redirecting output to a log file or /dev/null, pass any parameters as json or serialized (use escapeshellarg()), the exec will return 0 immediately (no error); or
use php's ignore_user_abort(), send a Connection: close header, flush any output buffers as well as a normal flush(). Put any slow code after that. You'll need to test this under Nginx.
Either way, return a 1xx code to signify acceptance but no response. And it's up you to make sure your script doesn't run forever; give it a heartbeat so it touch()es a file every so often. If the file is old and it's still running, kill it.
Thanks to #Walf's answer combined with this example from the php site, this SO answer and a little fiddling, this appears to be a solution for nginx that requires no messing with any php or nginx ini or conf files.
$start = microtime(true);
ob_end_clean();
header("Connection: close\r\n");
header('X-Accel-Buffering: no');
header("Content-Encoding: none\r\n");
ignore_user_abort(true); // optional
ob_start();
echo ('Text user will see');
$size = ob_get_length();
header("Content-Length: $size");
ob_end_flush(); // Strange behaviour, will not work
flush(); // Unless both are called !
ob_end_clean();
sleep(35); // simulate something longer than default 30s timeout
$time_elapsed_secs = microtime(true) - $start;
echo $time_elapsed_secs; // you will never see this!
Or, at least, it works perfectly for what I want it to do. Thanks for the answers.
I write the php code in iis to serve file for download with speed limit, so i need to use sleep function for the speed limit.
Here, few lines of my code:
set_time_limit(0);
while(!feof($file))
{
echo fread($file, 1024*10);
ob_flush();
flush();
sleep(1);
if (connection_status()!=0)
{
#fclose($file);
exit;
}
}
But the browser say: 'Waiting for mysite'. If i remove sleep(1) everything is right. I also test in apache and everything is right too.
So I have a problem in IIS with the sleep function.
You need to have your server properly configured for that. TBH you should use something on the server to do that, rather then relying on PHP, the sleep(1); causes it to send a chunk, pause, send a chunk pause, etc. It does not maintain 10kbps but goes from like 500kbps for a second to 0 kbps for a second, it may average out to 10kbps, but it is not the same and some programs won't treat it correct and may terminate the download. You should look into QoS (How to Limit Download Speeds from my Website on my IIS Windows Server?)
What exactly is the problem with IIS? Note that waiting for 1 second will mean that your script may exceed the timeout limit (this can be as low as 30 seconds) so IIS will kill your script.
If you want to serve large files, I recommend serving them directly from IIS and using IIS' built-in rate limiter rather than via PHP.
See here: http://www.iis.net/configreference/system.applicationhost/sites/site/limits
I have a site hosted on rackspace cloud sites. I have a troubleshooting script I am trying to run to figure out some problems with the site.
Cloud sites has a 30 second timeout and it is timing out before the results page can load. I spoke with their support and they advised me to put a page loading script at the top of the php file to keep the connection open but I have no idea how to do that and the googling I have done hasnt been much help.
The script I am trying to run is too long to include here but if anyone needs it you can find it here http://forum.joomla.org/viewtopic.php?f=621&t=582860
edit: so no matter what I set the execution time to in the script the load balancers rackspace uses will still timeout after 30 seconds. they have told me to run a 'page loading' script at the beginning of the script to keep the connection open so I am about to start looking into how to do that.
You could try the set_time_limit() function:
http://php.net/manual/en/function.set-time-limit.php
By default, a PHP script times out after 30 seconds.
Use the set_time_limit( int $seconds ) function to extend the maximum execution time.
You can also use ini_set() and set the max_execution_time:
ini_set("max_execution_time", 300);
EDIT
if the above doesn't work, then they probably use a secondary mechanism to timeout blocking connections. What you could try in this situation is to flush some data at a regular interval.
ob_start(); // enable output buffering
// output something at regular interval
echo " ";
ob_flush();
// at end of script
ob_end_flush();
Hope this helps.
I'm running really long task in php. It's a website crawler and It has to be polite and sleep for 5 seconds each page to prevent server overloading. Script starts with:
ignore_user_abort(1);
session_write_close();
ob_end_clean();
while (#ob_end_flush());
set_time_limit(0);
ini_set('max_execution_time',0);
After few hours (between 3-7h) script dies without any visible reason.
I've checked
apache error log (nothing)
php_errors.log (nothing)
output for errors (10 578 467b of debug output, no errors)
memory consumption (stable, around 3M from memory_get_usage(true) checked every 5 sec, limit set to 512M)
It's not browser, cause I was using wget and chrome to check with the similar reason.
Output is sent to browser every 2-3 seconds, so I don't think that's the fault + I ignore user abort.
Is there any other place I can check to find the issue?
I think there's a problem in the rest of your script, not Apache.
Try profiling your application using the register_tick_function with a light profiler like this and logging the memory usage, may be that.
I'm trying to make a PHP script, I have the script finished but it takes like 10 minutes to finish the process it is designed to do. This is not a problem, however I presume I have to keep the page loaded all this time which is annoying. Can I have it so that I start the process and then come back 10mins later and just view the log file it has generated?
Well, you can use "ignore_user_abort(true)"
So the script will continue to work (keep an eye on script duration, perhaps add "set_time_limit(0)")
But a warning here: You will not be able to stop a script with these two lines:
ignore_user_abort(true);
set_time_limit(0);
Except you can directly access the server and kill the process there! (Been there, done an endless loop, calling itself over and over again, made the server come to a screeching stop, got shouted at...)
Sounds like you should have a queue and an external script for processing the queue.
For example, your PHP script should put an entry into a database table and return right away. Then, a cron running every minute checks the queue and forks a process for each job.
The advantage here is that you don't lock an apache thread up for 10 minutes.
I had lots of issues with this sort of process under windows; My situation was a little different in that I didn't care about the response of the "script"- I wanted the script to start and allow other page requests to go through while it was busy working away.
For some reason; I had issues with it either hanging other requests or timing out after about 60 seconds (both apache and php were set to time out after about 20 minutes); It also turns out that firefox times out after 5 minutes (by default) anyway so after that point you can't know what's going on through the browser without changing settings in firefox.
I ended up using the process open and process close methods to open up a php in cli mode like so:
pclose(popen("start php myscript.php", "r"));
This would ( using start ) open the php process and then kill the start process leaving php running for however long it needed - again you'd need to kill the process to manually shut it down. It didn't need you to set any time outs and you could let the current page that called it continue and output some more details.
The only issue with this is that if you need to send the script any data, you'd either do it via another source or pass it along the "command line" as parameters; which isn't so secure.
Worked nicely for what we needed though and ensures the script always starts and is allowed to run without any interruptions.
I think shell_exec command is what you are looking for.
However, it is disables in safe mode.
The PHP manual article about it is here: http://php.net/shell_exec
There is an article about it here: http://nsaunders.wordpress.com/2007/01/12/running-a-background-process-in-php/
There is another option which you can use, run the script CLI...It will run in the background and you can even run it as a cronjob if you want.
e.g
> #!/usr/bin/php -q
<?php
//process logs
?>
This can be setup as a cronjob and will execute with no time limitation....this examples is for unix based operation system though.
FYI
I have a php script running with an infinite loop which does some processing and has been running for the past 3 months non stop.
You could use ignore_user_abort() - that way the script will continue to run even if you close your browser or go to a different page.
Think about Gearman
Gearman is a generic application framework for farming out work to
multiple machines or processes. It allows applications to complete
tasks in parallel, to load balance processing, and to call functions
between languages. The framework can be used in a variety of
applications, from high-availability web sites to the transport of
database replication events.
This extension provides classes for writing Gearman clients and
workers.
- Source php manual
Offical website of Gearman
In addition to bastiandoeen's answer you can combine ignore_user_abort(true); with a cUrl request.
Fake a request abortion setting a low CURLOPT_TIMEOUT_MS and keep processing after the connection closed:
function async_curl($background_process=''){
//-------------get curl contents----------------
$ch = curl_init($background_process);
curl_setopt_array($ch, array(
CURLOPT_HEADER => 0,
CURLOPT_RETURNTRANSFER =>true,
CURLOPT_NOSIGNAL => 1, //to timeout immediately if the value is < 1000 ms
CURLOPT_TIMEOUT_MS => 50, //The maximum number of mseconds to allow cURL functions to execute
CURLOPT_VERBOSE => 1,
CURLOPT_HEADER => 1
));
$out = curl_exec($ch);
//-------------parse curl contents----------------
//$header_size = curl_getinfo($ch, CURLINFO_HEADER_SIZE);
//$header = substr($out, 0, $header_size);
//$body = substr($out, $header_size);
curl_close($ch);
return true;
}
async_curl('http://example.com/background_process_1.php');
NB
If you want cURL to timeout in less than one second, you can use
CURLOPT_TIMEOUT_MS, although there is a bug/"feature" on "Unix-like
systems" that causes libcurl to timeout immediately if the value is <
1000 ms with the error "cURL Error (28): Timeout was reached". The
explanation for this behavior is:
[...]
The solution is to disable signals using CURLOPT_NOSIGNAL
pros
No need to switch methods (Compatible windows & linux)
No need to implement connection handling via headers and buffer (Independent from Browser and PHP version)
cons
Need curl extension
Resources
curl timeout less than 1000ms always fails?
http://www.php.net/manual/en/function.curl-setopt.php#104597
http://php.net/manual/en/features.connection-handling.php
Zuk.
I'm pretty sure this will work:
<?php
pclose(popen('php /path/to/file/server.php &'));
echo "Server started. [OK]";
?>
The '&' is important. It tells the shell not to wait for the process to exit.
Also You can use this code in your php (as "bastiandoeen" said)
ignore_user_abort(true);
set_time_limit(0);
in your server stop command:
<?php
$output;
exec('ps aux | grep -ie /path/to/file/server.php | awk \'{print $2}\' | xargs kill -9 ', $output);
echo "Server stopped. [OK]";
?>
Just call StartBuffer() before any output, and EndBuffer() when you want client to close connection. The code after calling EndBuffer() will be executed on server without client connection.
private function StartBuffer(){
#ini_set('zlib.output_compression',0);
#ini_set('implicit_flush',1);
#ob_end_clean();
#set_time_limit(0);
#ob_implicit_flush(1);
#ob_start();
}
private function EndBuffer(){
$size = ob_get_length();
header("Content-Length: $size");
header('Connection: close');
ob_flush();ob_implicit_flush(1);
}