Ratchet Revolt Prometheus Exporter

What is Revolt?

Revolt is a rock-solid event loop for concurrent PHP applications.

• https://revolt.run/
• https://github.com/revoltphp/event-loop

What is Ratchet?

Ratchet is a loosely coupled PHP library providing developers with tools to create real time, bi-directional applications between clients and servers over WebSockets.

• http://socketo.me/
• https://github.com/ratchetphp/Ratchet

What is ReactPHP event loop?

Ratchet based on ReactPHP event loop but to use native fibers, the loop can be replaced to Revolt event loop by ReactAdaptor

• https://github.com/amphp/react-adapter/tree/v3 - for Amphp v3

What is prometheus_client_php?

This library uses Redis or APCu to do the client side aggregation. If using Redis, we recommend running a local Redis instance next to your PHP workers.

• https://github.com/PromPHP/prometheus_client_php

Installation & Usage

cp .env.example .env
cp mysql/.env.example mysql/.env
docker-compose up -d

HTTP server starts at: http://${HTTP_HOST}:80/metrics

Usage (docker)

docker build -t ratchet_revolt .
docker run -it -p 80:80 ratchet_revolt

Usage (php)

composer install
php index.php

Example

/**
 * Set redis options
 * @see https://github.com/promphp/prometheus_client_php#usage
 */
RedisStorage::setDefaultOptions([
    'host' => 'redis',
    'port' => 6379,
    'password' => null,
    'database' => 0,
    'timeout' => 0.1, // in seconds
    'read_timeout' => '10', // in seconds
    'persistent_connections' => false
]);

/**
 * Set mysql options
 */
DB::setDefaultOptions([
    'host' => 'mysql',
    'port' => '3306',
    'user' => 'mysql',
    'password' => 'mysql',
    'db' => 'db'
]);

// Example gauge from mysql
$gauge = $registry->getOrRegisterGauge('rpe', 'testTable', 'Value from mysql');
$loop->addPeriodicTimer(1, function () use ($gauge) {
    $query = new Query();
    $query
        ->select('value')
        ->from('testTable')
        ->fetch()
        ->then(function (ArrayCollection $result) use ($gauge) {
            $query = new Query();
            $newValue = $result->first()['value'] + 1;
            $query
                ->update('testTable')
                ->set(['value' => $newValue])
                ->execute()
                ->then(function () use ($newValue, $gauge) {
                    $gauge->set($newValue);
                    echo $newValue . PHP_EOL;
                });
        });
});

// Example gauge from http
$client = new Browser(null, $loop);
$rates = $registry->getOrRegisterGauge(
    'rpe',
    'rates',
    'Value from http api ' . 'https://api.exchangerate.host/latest',
    ['ticker']
);
$loop->addPeriodicTimer(5, function () use ($client, $rates) {
    $client->get('https://api.exchangerate.host/latest')->then(function (ResponseInterface $response) use ($rates) {
        $json = json_decode((string) $response->getBody());
        foreach ($json->rates as $ticker => $rate) {
            $rates->set($rate, [$ticker]);
        }
    });
});

# HELP rpe_rates Value from http api https://api.exchangerate.host/latest
# TYPE rpe_rates gauge
rpe_rates{ticker="AED"} 3.745518
rpe_rates{ticker="AFN"} 91.629743
rpe_rates{ticker="ALL"} 116.842695
rpe_rates{ticker="AMD"} 418.291639
rpe_rates{ticker="ANG"} 1.836239
rpe_rates{ticker="AOA"} 440.461947
rpe_rates{ticker="ARS"} 131.771094
rpe_rates{ticker="AUD"} 1.478021

Other links

• https://github.com/reactphp/http - HTTP client
• http://socketo.me/docs/http - Ratchet HTTP\WS server
• https://wiki.php.net/rfc/fibers - PHP RFC