Ratchet: How to run socketo.me chat server on a remote VPS

[machomath]

I am running a Ratchet WebSocket for PHP (http://socketo.me/). It works fine at my localhost (WAMP), I have to run it via command line php chat-server.php and it works well. I have uploaded the website on a cloud based VPS, now I have to log into the VPS with the help of Putty on my laptop and then I run the same command again it works fine, as it starts listening to a opened port and sends out responses to the clients connected with that port. My issue is, as soon my laptop is offline the chat-server.php does not work anymore, it does not listen to the port and neither does it give out responses. My question is what could be a descent way to run chat-server.php so that even when the putty terminal (laptop) is offline it may still work. Any help is highly appreciated.

[michaelphipps]

You need a daemon to keep the program running.

I do this using systemd. I found the thread at https://serverfault.com/questions/730239/start-n-processes-with-one-systemd-service-file useful in understanding how to set up a daemon.

So, you might do something like this:

Assuming your chat server is at /var/www/vhosts/domain.com/bin/chat-server.php

Create the file /etc/systemd/system/chat-server.service

[Unit]
Description=Chat Server

[Service]
ExecStart=/usr/bin/php /var/www/vhosts/domain.com/bin/chat-server.php
StandardOutput=null
Restart=always
RestartSec=10

[Install]
WantedBy=multi-user.target

Enable the service:
sudo systemctl enable chat-server.service

Reload the daemon:
sudo systemctl daemon-reload

You can then use (start|restart|stop|status) like this:
sudo systemctl start chat-server.service

It is important that all paths in your code are absolute. To test this, try to run your code manually from a different directory on your server the way you have been:
ie: user@dev:/var/www# php /var/www/vhosts/domain.com/bin/chat-server.php

If the code still works correctly, then you're golden!

Finally, If you find that websocket disconnects due to inactivity after a while, you might want to use $loop->addPeriodicTimer() to add a heartbeat of sorts.

Hope it helps. Good luck!

[machomath]

Dear @michaelphipps
I am so happy to have your detailed response. I will work on it and post my feedback. Thank you very much for your help.

[machomath]

Dear @michaelphipps
Great, it worked for me, thank you very much. One quick and a basic question- my code is

use RatchetServerIoServer;
use RatchetHttpHttpServer;
use RatchetWebSocketWsServer;
use MyAppChat;

require dirname(__DIR__) . '/vendor/autoload.php';
require_once dirname(__DIR__) . '/src/chat.php';

$server = IoServer::factory(
new HttpServer(
new WsServer(
new Chat()
)
),
8888
);

$server->run();

Where should I put
$loop->addPeriodicTimer()

Thank you very much

[michaelphipps]

My apologies! My implementation is more like the example at http://socketo.me/docs/push which uses the event loop (except I use RabbitMQ, which I think is way easier to implement than ZeroMQ).

You're not using the event loop, so ignore my comment about addPeriodicTimer() for now.

[machomath]

Thank you very much indeed, the server is running without any issue:))
Now I am working to make it secure, I am trying
"Is there a real working example of using secure TLS ratchet websocket server? #609"
I have already installed letsencrypt certificate.
Thank you very much once again.

[michaelphipps]

Great!
At the risk of getting off topic, I have a working websocket server using TLS in production, and the code here https://github.com/ratchetphp/Ratchet/issues/#609#issuecomment-423882162 was instrumental in helping me to get it working.

The following code is untested, but might give you what you need.

$loop = React\EventLoop\Factory::create();

// Set up our WebSocket server for clients wanting real-time updates
$webSock = new React\Socket\Server('0.0.0.0:8443', $loop);
$webSock = new React\Socket\SecureServer($webSock, $loop, [
    'local_cert' => '/etc/letsencrypt/live/domain.com/fullchain.pem',
    'local_pk' => '/etc/letsencrypt/live/domain.com/privkey.pem',
    'allow_self_signed' => FALSE,
    'verify_peer' => FALSE
]);

$webServer = new Ratchet\Server\IoServer(
    new Ratchet\Http\HttpServer(
        new Ratchet\WebSocket\WsServer(
                new MyApp\Chat
        )
    ),
    $webSock
);

$loop->run();

You _should_ then be able to access this server with wss://domain.com:8443

Keep in mind when you test this from the comand line you need to use
sudo php /var/www/wherever/secure-chat.php
so that the script has permission to access the certificate correctly.

[machomath]

Great, thank you very much. I was working on the same lines but thought to use cert.pem instead of fullchain.pem. I am positive your code will save me hours of mining :) Actually sometimes I get a little confused that when to use cert.pem or chain.pem or fullchain.pem.
My profound regards

[machomath]

Thank you so much it mostly worked for me I used the following modified code.
use RatchetServerIoServer;
use RatchetHttpHttpServer;
use RatchetWebSocketWsServer;
use MyAppChat;

require dirname(__DIR__) . '/vendor/autoload.php';
require_once dirname(__DIR__) . '/src/chat.php';

$loop = ReactEventLoopFactory::create();
$webSock = new ReactSocketServer('0.0.0.0:8088', $loop);
$webSock = new ReactSocketSecureServer($webSock, $loop, [
'local_cert' => '/etc/letsencrypt/live/mydomain.com/fullchain.pem', // path to your cert
'local_pk' => '/etc/letsencrypt/live/mydomain.com/privkey.pem', // path to your server private key
'allow_self_signed' => FALSE, // Allow self signed certs (should be false in production)
'verify_peer' => FALSE
]);
$webServer = new RatchetServerIoServer(
new RatchetHttpHttpServer(
new RatchetWebSocketWsServer(
new Chat()
)
),
$webSock, $loop
);

$webServer->run();
Its running perfectly good for now, even with daemon :)

[machomath]

Hello @michaelphipps
As I mentioned earlier that I am using
`use RatchetServerIoServer;
use RatchetHttpHttpServer;
use RatchetWebSocketWsServer;
use MyAppChat;

require dirname(DIR) . '/vendor/autoload.php';
require_once dirname(DIR) . '/src/chat.php';

$loop = ReactEventLoopFactory::create();
$webSock = new ReactSocketServer('0.0.0.0:8088', $loop);
$webSock = new ReactSocketSecureServer($webSock, $loop, [
'local_cert' => '/etc/letsencrypt/live/mydomain.com/fullchain.pem', // path to your cert
'local_pk' => '/etc/letsencrypt/live/mydomain.com/privkey.pem', // path to your server private key
'allow_self_signed' => FALSE, // Allow self signed certs (should be false in production)
'verify_peer' => FALSE
]);
$webServer = new RatchetServerIoServer(
new RatchetHttpHttpServer(
new RatchetWebSocketWsServer(
new Chat()
)
),
$webSock, $loop
);

$webServer->run();`
to run a wss server. As you suggested I am running it through the daemon
[Unit]
Description=Chat Server

  [Service]
  ExecStart=/usr/bin/php /var/www/vhosts/domain.com/bin/chat-server.php
  StandardOutput=null
  Restart=always
  RestartSec=10

  [Install]
  WantedBy=multi-user.target

It runs well, all goes well- until it is inactive for some time, it still establishes wss connection but does not send back responses. It will be great if you can suggest something for it.

[michaelphipps]

I also noticed websockets shutting down after a few minutes. I found that it was the client that was timing out. If I refreshed the client connections, everything worked again. You'll recall I mentioned a periodic timer a while back! Now there's an event loop we can include it!

use Ratchet\Server\IoServer;
use Ratchet\Http\HttpServer;
use Ratchet\WebSocket\WsServer;
use MyApp\Chat;

require dirname(DIR) . '/vendor/autoload.php';
require_once dirname(DIR) . '/src/chat.php';

$chat = new Chat();

$loop = React\EventLoop\Factory::create();
$webSock = new React\Socket\Server('0.0.0.0:8088', $loop);
$webSock = new React\Socket\SecureServer($webSock, $loop, [
'local_cert' => '/etc/letsencrypt/live/mydomain.com/fullchain.pem', // path to your cert
'local_pk' => '/etc/letsencrypt/live/mydomain.com/privkey.pem', // path to your server private key
'allow_self_signed' => FALSE, // Allow self signed certs (should be false in production)
'verify_peer' => FALSE
]);
$webServer = new Ratchet\Server\IoServer(
new Ratchet\Http\HttpServer(
new Ratchet\WebSocket\WsServer(
$chat
)
),
$webSock, $loop
);

$loop->addPeriodicTimer(30, function() use ($chat) {
    foreach ($chat->clients as $client){
        $message['event']="heartbeat";    
        $client->send(json_encode($message));
    }
});

$loop->run();

Changes I've made:
Instantiated the Chat class so it can be called by your server and the periodic timer.
$chat = new Chat();

Added Periodic Timer Section to create a heartbeat that should keep the channel open

$loop->addPeriodicTimer(30, function() use ($chat) {
    foreach ($chat->clients as $client){
        $message['event']="heartbeat";
        $client->send(json_encode($message));
    }
});

I don't know how you send chat messages to attatched clients. My code just iterates over all connected clients and sends a heartbeat message. _BTW: If you aren't already, consider wrapping your messages in json, so you can send different types of messages._

Running the loop rather than the webserver
$loop->run();

That should be enough to keep the server responding to responses, but I want to add one more thing.

It's worth learning how autoloading works!
I should note that I'm still quite new to using PSR-4 (autoloading) but I think it's an important skill to have. There is a really good basic setup for autoloading in composer's documentation here: https://getcomposer.org/doc/01-basic-usage.md#autoloading

require dirname(DIR) . '/vendor/autoload.php';
require_once dirname(DIR) . '/src/chat.php';

would become

$loader = require  __DIR__.'/vendor/autoload.php';
$loader->addPsr4(MyApp\\', __DIR__.'/src');  

and you would add this to your composer.json

    "autoload": {
        "psr-4": {
            "MyApp\\": "src"
        }
    }

then you need to run
> composer dump-autoload
So that autoload knows about your Chat class.

[machomath]

Dear @michaelphipps
Thank you very much for a detailed response. I need some time to process it all and give feedback. I will let you know. Thank you very much once again.

[machomath]

Dear @michaelphipps
Thank you very much once again for all your help and very detailed replies. I wanted to give you my feedback after having a degree of confidence over my testing. So my issue was that after some time of inactivity my Ratchet server will apparently stop working, and we thought it was a Ratchet issue and we need to have a heartbeat loop to keep it running. Turned out to be that by default MySQL will timeout after 8 hours of inactivity and will disconnect the connection. So for now I have added a corn job for root which restarts the Ratchet server after 8 hours and its working for me.
0 0,8,16 * * * systemctl restart chat-server.service
I intend to make MySQL timeout to never as my next step. I have not done any load testing for now though. Thank you very much once again. I thought to give you an update.