[appserver-io/appserver] Multithreading in Windows

[ndamofli]

Hi there, I installed the windows version of appserver and i have a problem with multithreading.
I have a simple php script that runs an exec command and returns the output.
I am trying to run this script multiple times concurrently but my requests are processed one by one (serial).
I am using another (apache) server to invoke the requests to appserver via multi-curl.

[zelgerj]

Hi, could you paste your script here? it's will help a lot to understand whats intended to do. Cheers.

[ndamofli]

I am using phantomjs.exe (a headless browser) to create screenshots of websites.
My intention is to make multiple parallel queries to appserver's webserver like the following:

http://localhost:9080/phantom/phantom_bp.php?url=$url

The script phantom_bp.php contains:
$command = "phantomjs.exe phantom.js $url";
function exec_alt($cmd, $counter){
$return = exec($cmd, $output);
if (!$output) {
$return = "NOPHANTOM";
}
return $return;
}

I use multi-curl to invoke multiple requests from another script on another webserver.
The script works, but appserver processes the requests one by one.

[zelgerj]

Ok thanks for sharing you script. Is that script called from browser or another Webserver using another script which uses multicurl?... sorry for that questions... but i still can not follow you... could you visualize your request chain like.

1. Browser requests http://...
2. Triggered script via apache and mod-php uses multi_curl and requests http://...
3. Triggered script via appservers webserver requests phantomjs.exe

[ndamofli]

This script is called from chrome browser from another webserver (apache @ localhost:80) and it uses multicurl.
So the chain is as follows:

1. Browser (chrome) requests multi_update.php from apache server @ port 80
2. apache php script makes multiple requests to appserver (@ port 9080) via multi curl
3. php script in appserver requests phantomjs.exe
   Thank you so much for your time and effort

[zelgerj]

Ok what if you call the appserver script (@PORT 9080) directly from the browser. Does that work concurrently?

[ndamofli]

No it doesn't. I tried opening multiple chrome windows and they don't work concurrently

[zelgerj]

I guess exec under windows causes the process to block while the execution is in progress. You could try to replace the exec with error_log('simulate phantomjs to be executed');sleep(1); to see if it is still not concurrently.

[ndamofli]

Unfortunately i still have serial output. I opened 5 windows with sleep time 5secs and the request were processed one after another (not parallel)

[zelgerj]

Ok i'll check that on my windowz machine...

[ndamofli]

thank you zelgerj

[zelgerj]

hm sorry but i can not reproduce your problem. Parallel requests on a script with sleep(5) are processed all concurrently... some special on your configuration or windows system itself?!

[ndamofli]

well i didn't make any changes to the default configuration of appserver, and i'm only using a simple wamp server (for apache, php mysql) on a windows 7 64bit hexacore i7. bummer.

[ndamofli]

could u please send me a link of your installation.? maybe i have a wrong version of appserver (i downloaded it today from appserver's homepage)

[zelgerj]

The link should be ok... I'll create a test for that scenario, that checks if it is non-concurrent. I'll get back on you if it is ready...

[ndamofli]

Thank you very much Zelgerj.. Just to let you know, i installed appserver to another machine (win7 32 bit this time) and i had the same problem (tried the multiple windows & sleep script).

[zelgerj]

@ndamofli: Finally i'am not able to reproduce the problem. Could you setup a virtual machine and gimme access to it, so i can reproduce and debug the problem?

[wick-ed]

Hi @ndamofli ,

can you give us an update on this issue? We were not able to reproduce it here and would like to close it if the problem does not exist anymore.

[wick-ed]

Closed as not reproducable