Ratchet: Max connection limit of ratchet websocket

[sanjayinx]

Hi, I am new in ratchet web socket, and my application is like "FACEBOOK", so can i use the ratchet web socket in PHP(Laravel)? And also tell me : How many connections working concurrently?
Sorry for my English...

[k-vladyslav]

@sanjayinx I researched that question recently. Take a look at this https://github.com/ratchetphp/Ratchet/issues/300 and also open https://rtcamp.com/tutorials/linux/increase-open-files-limit/.

TLDR: 1024 cocurrent connections in default PHP build, can be recompiled with higher limit. Also You need to raise Your OS nofile limit. But better build scalable Ratchet cluster from the beginning :)

[Mecanik]

Unfortunately I have the same problem. I tested on both windows and linux ( on linux everything increased and optimised ) and I cannot make more than 254 connections. This is really frustrating and it would be nice to hear some advice/solutions.

[alexslipknot]

With PHP 7.1 we have a limit 255. Could it be cause of PHP build?

[Mecanik]

@alexslipknot I have already found a solution for this, please see: https://github.com/ratchetphp/Ratchet/issues/300

[alexslipknot]

@Mecanik thanks. So I have to use Event instead of LibEvent or SocketStream? I'm not exactly using Ratchet but project is very similar. I'm afraid that moving to another extension will case a lot of work. Maybe it is possible to increase stream_socket limit at least with rebuilding PHP?

[Mecanik]

@alexslipknot You can increase anything you want, it will still not pass 1024 connections. Using another extension would not affect anything, but you can always test and see. If you use PHP 7 then use "event" and it will be fine.

[alexslipknot]

@Mecanik alright, thank you, I'll try :)

[alexslipknot]

Well. After installing pecl extension "Event" and implementing some websocket-server I found that maximum connections still 255. So I guess there is system restrictions.
I'm using Debian on docker with PHP 7.1.7
Maybe I'm doing something wrong? Here is limits for process:

[Mecanik]

@alexslipknot Ok, you have gone so far so do not change anything back. Tell me, are you using PHP-FPM ?

[alexslipknot]

@Mecanik Yes. Indeed. But anyway I'm starting script within console, so I guess it is CLI in my case

[Mecanik]

@alexslipknot Ok, have a look at my code above and use it. See what the values are, based on that we can find out where the limit is. I had it before, but I cannot remmeber 100% where. Please use the code I posted above.

[alexslipknot]

@Mecanik if you're talking about issue300 - I think there is no need to check if (class_exists)
Because my example using definitely Event. So my code looks like:

Starting server:

    $this->base = new EventBase();
    $this->event = new EventListener($this->base, [$this, 'accept'], $this->base, EventListener::OPT_CLOSE_ON_FREE | EventListener::OPT_REUSABLE, -1, $this->server);

And accept connection method:

public function accept($listener, $connectionId, $address, $id)
{
    $buffer = new EventBufferEvent($this->base, $connectionId, EventBuffer::OPT_CLOSE_ON_FREE);
    $this->clients[$connectionId] = $connectionId;
    echo "connection count: " . count($this->clients) . "\n";
    // ... some more stuff
}

[Mecanik]

@alexslipknot Well this is where you are wrong, just because you manually call EventBase() does not mean it will use the "event" extension. I tried the same thing before and had no results, until I checked with the code I told you above.

Make sure you are using "even" extension, then the factory will use ExtEventLoop which is what you need.
Make sure the limits are increased accordingly: https://easyengine.io/tutorials/linux/increase-open-files-limit/
Make sure if you are using PHP-FPM, that you have edited /etc/php/7.0/fpm/php-fpm.conf like so:

; Set open file descriptor rlimit for the master process.
; Default Value: system defined value
rlimit_files = 65536

; Set max core size rlimit for the master process.
; Possible Values: 'unlimited' or an integer greater or equal to 0
; Default Value: system defined value
rlimit_core = unlimited

Then give it a try, but please check what I said.

[alexslipknot]

@Mecanik Thanks for helping me. I'm really appreciate that.
So about extension: no, when I call new EventBase without extension - it will terminate process immediately with error:

Undefined class

So I'm definitely using Event
But! Event listener is just a worker that starting inside from master. And my master using stream_socket_server to create server. So I guess that can be reason of limitation.
EventListener accept socket in $target param. So should I use something else? In my case this is stream_socket that listen tcp connection over SSL over wss protocol.

[Mecanik]

@alexslipknot I'm trying to help you, but in order to do that I need you to answer my questions...

Did you do any of the steps I told you to do ?

[alexslipknot]

@Mecanik yes I did. Also I've modified php.conf with unlimited instead of 0 (but it's just an alias of zero)

[Mecanik]

@alexslipknot Please post your configurations on pastebin, set them to expire in like 1 hour so nobody will "take" them. I shall have a look and see what is the actual problem. Please include all your PHP configs, and /etc/security/limits.conf and /etc/pam.d/common-session.

[alexslipknot]

I uploaded structured archive with configs.
@Mecanik by the way: I already tried with EventListener (server now using it as $server) instead of stream_socket_server but still no luck. :(

[Mecanik]

@alexslipknot Checking your configuration, I found the first problem. You are not using "event"properly, I do not think Ratchet detects it. ( react )

So please do the following:

-Create "event.ini" in "\etc\php\7.1\mods-available" and insert: "extension=event.so"

• Perform the following 2 commands:

ln -sf /etc/php/7.1/mods-available/event.ini /etc/php/7.1/fpm/conf.d/20-event.ini
ln -sf /etc/php/7.1/mods-available/event.ini /etc/php/7.1/cli/conf.d/20-event.ini

Then please remove "extension=event.so" from "\etc\php\7.1\fpm\php.ini" because it will not load it here anyway.

Then do: service php7.1-fpm restart

Afterwards please start the server with: "exec /usr/bin/php7.0 index.php" and do your test.

It might not load even now the extension properly, so to further assist you please do exactly the steps I mentioned, and insert in your "index.php" or whatever file you use this:

if (function_exists('event_base_new')) {
            echo "\033[0m We can use LibEventLoop!!" . PHP_EOL;
        } elseif (class_exists('libev\EventLoop', false)) {
            echo "\033[0m We can use LibEvLoop!!" . PHP_EOL;
        } elseif (class_exists('EventBase', false)) {
            echo "\033[0m We can use ExtEventLoop!!" . PHP_EOL;
        } 
        else 
        {
            echo "\033[0m We can use StreamSelectLoop!!" . PHP_EOL;
        }

So we can see what is the server using when it starts.

[alexslipknot]

@Mecanik Even when I know that those things are the same and will not help to )) I did all steps that you mentioned above. And as I expected: We can use ExtEventLoop!!
So really I think that some limitations are in my docker container.

[Mecanik]

@alexslipknot Great stuff, so it's using the correct extension. Now we know that Ratchet is not limited anymore. Regarding the docker, if it's a container it may have limits from the parent machine! So no matter what we do, it may not work.

Why don't you try with a normal VPS ? But with the same configurations...

[alexslipknot]

@Mecanik ))) Thanks for your optimism. I'll try it on real server. Anyway with steam_socket real server has limits with 255 connections. Well... any manipulations on the real production server scare me because I haven't test environment. Only production. But anyway I'll write here the results.

[alexslipknot]

Well, At least I got what's the problem. These limitations are from operating system. So on Debian 7 I have limits with 255 connections and on Debian 8 I have limits with 199 connections. I tried not only with PHP. I also tried with example on C++ ... So I have to look how to avoid those limits on Debian.

[Mecanik]

@alexslipknot OS limits are easy to increase, and they should increase; but if you are running as a Container it might not be possible because the "mother host" is restricting it and there is nothing you can do.

[alexslipknot]

Finally! I found the solution! Thanks a lot for everyone!
Problem was: I was testing connection limits from one browser. But the browser has a limit for it :)