A prometheus client library written in PHP

This library uses Redis to do the client side aggregation. We recommend to run a local Redis instance next to your PHP workers.

Why Redis?

Usually PHP worker processes don't share any state.

We decided to use Redis because:

• It is easy to deploy as a sidecar to the PHP worker processes (see docker-compose.yml).
• It provides us with easy to use concurrency mechanisms we need for the metric aggregation (e.g. incrByFloat).

We think this could be implemented with APCu as well and we might do so in the future. Of course we would also appreciate a pull-request.

Usage

A simple counter:

\Prometheus\CollectorRegistry::getDefault()
    ->registerCounter('', 'some_quick_counter', 'just a quick measurement')
    ->inc();

Write some enhanced metrics:

$registry = \Prometheus\CollectorRegistry::getDefault();

$counter = $registry->registerCounter('test', 'some_counter', 'it increases', ['type']);
$counter->incBy(3, ['blue']);

$gauge = $registry->registerGauge('test', 'some_gauge', 'it sets', ['type']);
$gauge->set(2.5, ['blue']);

$histogram = $registry->registerHistogram('test', 'some_histogram', 'it observes', ['type'], [0.1, 1, 2, 3.5, 4, 5, 6, 7, 8, 9]);
$histogram->observe(3.5, ['blue']);

Expose the metrics:

$registry = \Prometheus\CollectorRegistry::getDefault();
$registry = CollectorRegistry::getDefault();

$renderer = new RenderTextFormat();
$result = $renderer->render($registry->getMetricFamilySamples());

header('Content-type: ' . RenderTextFormat::MIME_TYPE);
echo $result;

Change the Redis options (the example shows the defaults):

\Prometheus\Storage\Redis::setDefaultOptions(
    [
        'host' => '127.0.0.1',
        'port' => 6379,
        'timeout' => 0.1, // in seconds
        'read_timeout' => 10, // in seconds
        'persistent_connections' => false
    ]
);

Also look at the examples.

Development

Dependencies

• PHP 5.3/5.6/7.0
• Composer
• Redis

Start a Redis instance:

docker-compose up Redis

Run the tests:

composer install

# when Redis is not listening on localhost:
# export REDIS_HOST=192.168.59.100
./vendor/bin/phpunit

Black box testing

Just start the nginx, fpm & Redis setup with docker-compose:

composer require guzzlehttp/guzzle=~6.0
docker-compose up
vendor/bin/phpunit tests/Test/BlackBoxTest.php